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Google Nest Learning Thermostat (4th gen) Installation Guide

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Nest Learning Thermostat (4th gen)

Pro Installation and Conﬁguration Guide

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Name	Google Nest Learning Thermostat (4th gen) Installation Guide
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Google Nest Learning Thermostat (4th gen) Installation Guide Overview

Summary of Contents

Page 1: Nest Learning Thermostat (4th gen) Pro installation and configuration guide
Page 2: How to use this document Getting started with the Nest Learning Thermostat (4th gen) If you’re referencing this document, you are probably familiar with the Nest Learning Thermostat (4th gen). Beginner’s guide to Nest thermostats Nest thermostat settings menu Nest Pro support articles Nest thermostat information menu What you'll see on a Nest thermostat How to tell which Nest thermostat you have Manage homes and products in the Nest app Troubleshoot Nest thermostat help codes
Page 3: Nest Learning Thermostat Pro Installation and Configuration Guide General Information Thermostat navigation Key features and functions Compatibility overview Technical Specifications Technical information Power requirements What’s in the box Setup and Configuration Pro setup walkthrough Heat pumps Humidifiers and dehumidifiers Fan control Troubleshooting Handling unusual wiring Heat pump lockout temperatures Installation Overview Pro setup steps Supported wiring Compatibility FAQ and notes Wiring Diagrams Common wire and power sharing How to and reference Wiring errors General troubleshooting Quick Reference Conventional systems Heat pump systems Dual fuel systems Multi-speed fans Glossary Humidifiers and dehumidifiers Unique wiring situations
Page 4: How to use this document This installation and configuration guide includes additional information that a professional installer needs to install and service the Nest Learning Thermostat (4th gen). This document is intended for any individual working with Nest thermostats in a professional capacity, primarily focusing on HVAC professionals. It may also be useful to professionals in other industries, such as builders, home security, custom integration, energy efficiency, and electrical. This document provides valuable information for a wide range of roles within these industries, including technicians, installers, sales representatives, managers, engineers, architects, support personnel, operations staff, and their respective wholesale partners. When we use the term pro in this document, we are specifically referring to HVAC technicians or installers. Some section headers are links to Google support pages with more detailed information about the feature or function. The table of contents contains hyperlinks to the pages and sections within the document. There is a glossary at the end of this document that contains links to the pages where these terms are found within the document, as well as links to Google support articles about that term. Save this document as a PDF on your phone or tablet so you can reference it when you need it.
Page 5: General Information - Nest Pro Program What is the Nest Pro Program? The Nest Pro program is designed to provide great benefits for professional installers, like special pricing, pro-exclusive extended warranties, Nest Pro Rewards, and pro-specific support. What is a Nest Pro ID? Your Nest Pro ID is your company’s unique 6-digit ID. HVAC System Health Monitor HVAC System Health Monitor, built into all Nest thermostats, looks out for system issues and lets customers know when something might be wrong. Important: Select “Receive System Health monitoring repair requests from customers” on your settings page to opt in to have your company’s contact information surfaced on the alerts. Other Nest Pro Benefits Enter your Nest Pro ID at each installation to automatically earn points for each thermostat you install. Use reward points Use reward points to invest in your business with more Nest products to boost your bottom line. Extended warranties Enter your Nest Pro ID at installation to unlock extended warranties on all Nest thermostats, only available on devices installed by Nest Pros. How to sign up Signing up to be a Nest Pro is simple and takes very little time.
Page 6: Installation overview Nest Pro warranty eligibility includes an extended pro warranty when purchased from and installed by a registered Nest Pro. The pro-exclusive warranty adds 3 years of additional coverage, totaling 5 years of warranty coverage. Entering the Pro ID during installation activates the customer’s extended warranty under specific criteria. The thermostat must be sold and installed by a registered Nest Pro. The Nest Pro ID must be input during the setup installation. The thermostat needs to be connected to Wi-Fi and added to the customer’s Google Home or Nest account. Customers can submit a warranty claim directly with Google online using the Warranty Checker. The warranty process may differ depending on the reported issue. A Nest Pro can replace thermostats according to the warranty process specific to the wholesaler. Customers should reach out to their place of purchase for specific warranty processes.
Page 7: General Information - Key Features and Functionality HVAC System Health Monitor is a feature on Nest thermostats that can help homeowners identify potential issues with eligible heating, ventilation, and air conditioning (HVAC) systems. If a potential issue is detected, Google Nest will send the homeowner an alert via email and/or a Google Home app notification. Sometimes, HVAC systems show warning signs that they are having issues. Google Nest may send the homeowner an email alert or a Google Home app notification if a warning sign is detected. HVAC System Health Monitor is not meant to replace the diagnosis of a qualified HVAC professional. HVAC System Health Monitor will only include the contractor’s contact information if they are a registered Nest Pro. During enrollment, the legal signing authority must opt in to have the company’s info surface to the customer. Homeowners can opt out of urgent email alerts, early warning emails, or Google Home app notifications by turning them off within the app. Homeowners cannot opt out of HVAC urgent alerts since they raise serious system issues that they need to be aware of.
Page 8: General Information - Key Features and Functionality Types of Alerts If a Nest thermostat detects a potential issue that may require immediate attention, Google Nest will send the homeowner an urgent alert as soon as a problem is detected. If Google Nest detects an issue that should be fixed soon, an early warning alert will be sent to the homeowner within a week of detecting the problem. System Health Monitor Alerts Home fails to heat as expected, even while the system is running. Home fails to cool as expected, and user may hear a clicking noise. Furnace shuts down intermittently, which may cause equipment damage and safety hazard. Your system briefly stopped heating your home several times. Your A/C system briefly lost power several times. Important: HVAC System Health Monitor is not meant to replace the diagnosis of a qualified HVAC professional.
Page 9: Key features and functionality include the ability to create or adjust the temperature schedule in the Google Home app. Temperature presets allow customization for when you're home, away, sleeping, and more. Users can add a preset to the schedule or adjust the temperatures of each preset. The thermostat can be set to “hold” a specific preset or custom setpoint for an extended period. There are three ready-made presets: Comfort, Sleep, and Eco. Users can adjust the temperatures of these presets or add custom presets. Installing a Nest Temperature Sensor provides the option to schedule when the thermostat observes a particular sensor. The main schedule page is available for managing settings. Editing the schedule is a feature of the thermostat.
Page 10: Key features and functionality include Smart Schedule, which learns from users' temperature adjustments and presence patterns over time. The Nest Learning Thermostat will suggest changes to optimize schedules for comfort and energy savings. Users can choose to automatically apply changes, review them, or disable Smart Schedule completely. The thermostat learns the most during the first week of use but continues to learn over time. Users are notified when a change is made to their schedule, even if automatic application is selected. The thermostat visually indicates when it is learning from manual adjustments. Users can check the History tab in the Google Home app to see changes made. Smart Schedule will only adjust setpoints or scheduled times of ready-made presets: Comfort, Sleep, and Eco. Users can reset smart schedule learning if their habits change significantly. Notifications must be enabled in the Google Home app to receive updates on changes.
Page 11: Key features and functionality include Energy Shift, which integrates with energy savings initiatives from local utility providers. Energy Shift consists of three main features: Time of Use, Cleaner Energy, and Rush Hour Rewards. Time of Use allows users to prioritize using cheaper energy based on their utility provider's rates. Users can add a rate code from their utility in the Google Home app to inform the thermostat of energy pricing. When enabled, the thermostat adjusts system operation to avoid using energy during peak pricing periods. Users receive notifications about any schedule or setpoint adjustments made by the thermostat. A summary of adjustments can be viewed in the Time of Use page of the Google Home app. If a Time of Use rate is unavailable, users can set a manual Peak Period for the thermostat. This feature is beneficial for customers with solar or battery systems or those whose utility hasn't integrated with Google services. The manual setting allows for continued energy savings even without direct integration.
Page 12: Key features and functionality include Energy Shift, which prioritizes cleaner energy and rush hour rewards. Energy Shift integrates with energy savings initiatives from local utility providers. The main features under Energy Shift are Time Of Use, Cleaner Energy, and Rush Hour Rewards. The Prioritize Cleaner Energy feature adjusts the HVAC schedule based on the source of power generation. When enabled, the thermostat can shift operation to times when cleaner energy sources like solar and wind are available. Rush Hour Rewards allows users to enroll their thermostat with utility companies to adjust heating or cooling during peak energy consumption. Participants in Rush Hour Rewards may receive rebates or bill credits, varying by utility partner. Users retain control over their thermostat settings even when enrolled in utility programs. The thermostat provides real-time information about power generation sources. For more information, users are encouraged to check with their utility provider.
Page 13: Key features and functionality include Seasonal Savings, which users can opt into during summer or winter. The goal is to find energy savings without sacrificing comfort. This feature gradually adjusts preset temperatures over a 3-5 week period. After a small adjustment, it waits for the user to experience the new temperature before making further changes. If discomfort is detected, Seasonal Savings will stop adjustments and return to a comfortable temperature. If a device lacks a schedule, opting into Seasonal Savings will create a basic schedule with Sleep and Comfort presets.
Page 14: Key features and functionality include natural heating and cooling. Natural heating and cooling determines when to pause heating or cooling to allow the temperature to naturally rise or fall. On a sunny morning, the thermostat might pause heating because the sun is helping to keep the house warm. On a cool evening, the thermostat might pause cooling and let the temperature fall naturally. The thermostat uses outdoor temperature data to determine when to activate natural heating and cooling. The feature can be enabled or disabled using the Google Home app. The thermostat will show a natural heating/cooling message when the feature is actively preventing heating or cooling.
Page 15: Key features and functionality include fan and ventilation control. The Nest Learning Thermostat can control the HVAC system fan if there is a wire for independent control. The fan can be scheduled to run for 15-60 minutes each hour every day and can also be manually engaged. Users will be prompted to choose a fan speed when manually activating a multi-speed fan. Ventilation systems can be manually activated with a timer or with the system fan. Users will need to set the “Required daily ventilation” from 2-24 hours, with a default of 18 hours. The Smart Ventilation feature uses outdoor temperature, air quality, and user behavior to optimize ventilation usage. It may not run the ventilation system if outdoor air quality is poor. This feature can activate a ventilation system at varying times while meeting the user-defined ventilation threshold.
Page 16: Key features and functionality include Adaptive Comfort and Adaptive Eco. The Adaptive Eco feature helps save energy when users are away while maintaining comfort upon their return. It adjusts Eco temperatures based on past heating and cooling performance and forecasted weather. Adaptive Eco activates during Auto-Eco periods, requiring users to set up Home & Away Routines in the Google Home app. Adaptive Comfort adjusts Comfort temperatures based on non-temperature conditions like indoor humidity and forecasted weather. This feature allows the thermostat to respond to changing conditions for optimal comfort. Users can enable or disable Adaptive Comfort through the Google Home app.
Page 17: Key features and functionality include automating home devices based on location with Home & Away Routines. Users are encouraged to migrate from a Nest account to a Google account to utilize this feature. Routines can be created in the Google Home app or as scripted automation on the web. Presence is determined using the user's phone location and smart device sensors. Users can select which devices will determine presence. Setting up Home & Away Routines requires the Google Home app and potentially migrating their Nest account. The Nest Learning Thermostat can be added to routines for automatic adjustments based on presence. The thermostat can utilize features like Adaptive Eco and Early On preconditioning when included in routines. Home & Away Routines work seamlessly with the Nest app's Home/Away Assist, despite the name changes.
Page 18: Key features and functionality include Early On and Heat Pump Balance. Early On allows users to schedule their thermostat based on desired temperature arrival times. Users can enable Early On for both cooling and heating setpoints when the home is occupied. The feature also allows pre-heating or pre-cooling while users are away, requiring Home & Away Routines to be activated. Heat Pump Balance optimizes the use of auxiliary heat based on user preferences for comfort or savings. Users can select priorities such as comfort, savings, balanced, or off, and the system will adjust accordingly. Heat Pump Balance must be disabled during Pro Setup to manually set certain parameters. The thermostat needs to be connected to Wi-Fi for Heat Pump Balance to function properly. Users with dual fuel systems cannot use Heat Pump Balance and must set parameters manually during Pro Setup. The compressor lockout temperature can still be adjusted even if Heat Pump Balance is enabled.
Page 19: Key features and functionality include sunblock, which compensates for direct sunlight affecting the thermostat's temperature sensor. With sunblock enabled, the user's home remains comfortable and true to the real temperature inside. Cool to dry is a feature that allows the compressor and fan to run longer after reaching the cooling setpoint to remove excess humidity. Cool to dry can be used with any air conditioner or heat pump, but its functionality varies based on the system's dehumidification mode. During pro setup, users can adjust settings for target humidity, minimum indoor temperature, and overcooling limits for cool to dry. Smart humidiﬁcation automatically reduces target humidity based on outdoor weather to prevent condensation in cold weather. Airwave turns off the compressor shortly before reaching the target temperature and runs the fan alone to maximize energy savings. Airwave learns how much cooling can be achieved without the compressor and activates at the right time. Airwave may not activate in humid conditions as identified by the thermostat's built-in humidity sensor. In more humid climates, airwave might never activate.
Page 20: Key features and functionality include the Nest Leaf, which indicates when the thermostat is set to an energy-saving temperature. Time-to-Temp estimates how long it takes to heat or cool the home based on previous cycles. Safety Temperatures protect the home during extreme weather by activating heating or cooling even when set to off. Thermostat Lock prevents unauthorized changes to settings or temperature outside a restricted range. Air filter reminders can be enabled and are calculated based on forced air runtimes. The thermostat will still operate according to the user's schedule even when locked. Users can unlock the thermostat using a four-digit PIN code or through the app. The Nest Learning Thermostat learns equipment performance for more accurate Time-to-Temp estimates. Safety Temperatures help prevent issues like frozen pipes or overheating. Air filter reminders require user input on when the filter was last changed.
Page 21: Key features and functionality include utility rebates and programs available for Nest thermostats. Some rebates require enrollment in programs like Rush Hour Rewards. Nest thermostats use local weather data for temperature-dependent features. They connect to the internet via home Wi-Fi to read outdoor weather data without additional sensors. Outdoor temperatures affect compressor lockout temps, aux lockout temps, and dual fuel breakpoints. The thermostat will not engage a second stage unless the temperature changes direction within the first 15 minutes. If the temperature does not change, the thermostat will wait a specified time before upstaging. The second stage of heating or cooling activates with a 3.3°F adjustment, while the third stage requires a 7°F change. Auxiliary heat is disabled at the start of a heat cycle but may be enabled after a minimum delay if conditions are met.
Page 22: HVAC system compatibility
Page 23: HVAC system compatibility The Nest Learning Thermostat (4th gen) works with most 24V systems, including gas, electrical, oil, forced air, heat pump, and radiant. Heating: 1, 2 and 3 stages (W1, W2, W3) Cooling: 1 and 2 stages (Y1, Y2) Fan (including multi-speed) (G or G1, G2, G3) Humidifier, dehumidifier (HUM, DEHUM) HRV, ERV, Exhaust Only, Supply ventilation Heat pump: with auxiliary/alternate and emergency heat (O/B, AUX, ALT, E) Power (C, Rh, Rc) Wi-Fi is required for software updates and remote control with the Google Home app.
Page 24: HVAC system compatibility specifications include power requirements and sensor details. The device has a built-in rechargeable lithium-ion battery. It uses less than 1 kWh per month with a voltage requirement of 20-30VAC. Startup current is 4VA, and standby current is 2VA. Battery voltage of 3.6V or higher is required for Wi-Fi connection and updates. Sensors include temperature, humidity, motion sense, and ambient light. The display is a 68 mm diameter circular liquid crystal with a resolution of 600x600 pixels. Box contents include the display, wiring plate, and mounting screws. The assembled weight is 195 g with a diameter of 98 mm. Additional items include a quick start guide and safety and warranty documentation.
Page 25: Installation overview provides a summary of the connections needed for the system. Conventional connectors are used for standard installations. Heat pump with auxiliary connections is specified for additional heating support. Heat connectors are essential for proper heat pump functionality. Stage 1 compressor relay is crucial for the initial cooling stage. Stage 2 compressor relay manages the second cooling stage. Fan relay controls the operation of the fan. Changeover valve relay is necessary for switching between heating and cooling modes. 24VAC power from the cooling transformer is required for operation. Emergency heat and humidification functions are included for enhanced climate control.
Page 26: Installation overview - Pro setup Key wiring and compatibility notes Must use an external transformer for a source of constant 20-30 VAC when using the power connector. If the boiler is DC powered, you must install a SSR between the transformer and terminal block. Nest thermostats will not work with zoned systems in which the thermostat does the activation and deactivation of the zoned dampers. Many zone panels will require an upgraded transformer when using a smart thermostat such as the Nest Learning Thermostat. The Nest Learning Thermostat supports a dedicated wire for emergency heat in the star terminal, but it is not required. Engaging the emergency heat function will activate the Aux heat strips as the primary heat source. The Nest Learning Thermostat does not modulate voltage; therefore, it cannot control variable speeds on the thermostat side. Some common terminals that we do not work with are non-standard HVAC terminals. If you see terminals labeled 1, 2, 3, or A, B, or D, there is a pretty good chance that the Nest Learning Thermostat will not work with the equipment. If all other terminals are standard HVAC wiring, you can proceed as normal, and you will just cap off the “S” wire and not use it.
Page 27: General Information Pro Setup allows a technician to install and configure a Nest Learning Thermostat on their own phone using the Google Home app. The Pro Setup process is faster than the customer install process and allows skipping basic instructions. Pro Setup prompts for a Nest Pro ID, activating an extended warranty and storing company contact information. Advanced Settings lets Nest Pros configure complex systems, including dual-fuel systems and ventilation systems. Some advanced settings are only available during the Pro Setup process and cannot be adjusted by the user afterward. The Nest Learning Thermostat uses solid-state switching, eliminating noise during system testing and activation. The Google Home app checks wire connections during installation and prompts for additional information if needed. The thermostat has two multifunctional terminals that can control various applications. The Google Home app will ask for equipment selection when using multifunctional connectors. The LED light on the baseplate indicates whether the thermostat is receiving power from the HVAC system.
Page 28: Installation overview provides an overview of the physical installation process of the Nest Learning Thermostat. It includes tips for providing a good experience for a customer. The document will guide through the Pro Setup process using the Google Home app. Some screens may differ depending on the equipment being configured. The Pro Setup process concludes with how the customer connects the thermostat to their Google Home app and account. The document explains available settings and important information about configuring complex systems. Wiring diagrams for compatible equipment are included in the last portion of this section. The Nest Learning Thermostat has a dedicated configuration process for Nest Pros in the Google Home app. This setup allows advanced settings configuration without the homeowner needing to be present. After completing the Pro Setup, the thermostat offers basic control and is ready for connection to a homeowner’s account.
Page 29: Installation overview - step-by-step Confirm system compatibility Before opening the Nest Learning Thermostat package, check all the wires connected to the current thermostat against the list of available connectors in this guide. Briefly test the HVAC system Test the heating, cooling, fan, and other system features with the current thermostat before installing the Nest Learning Thermostat. Turn off power to the HVAC system Turn off the power to the system to protect yourself and the equipment. Remove the old thermostat Before removing the old thermostat, take a quick picture of the wiring with your phone in case you need it for reference. Offer the customer installation finishing options You may need to cover up holes, old paint, or marks left by the old thermostat.
Page 30: Installation overview - step-by-step Install the Nest Learning Thermostat Run the wires through the center of the Nest Thermostat base and attach it to the wall using the screws provided. Use the built-in level for proper alignment. Configure the Nest Learning Thermostat Once the thermostat is physically installed, you will need to use the Google Home app to complete the Pro Setup process. Ensure that you have consulted equipment manuals for the optimal settings for your equipment configurations. Advanced settings available during Pro Setup include compressor lockout time and minimum compressor on time. Test heating and cooling This is vital to any installation in order to prevent a callback. Run each part of the system for a few minutes to ensure correct installation. The thermostat will require Wi-Fi to fully test the equipment and report any errors.
Page 31: Installation overview - step-by-step Help your customer pair the thermostat with the Google Home app. If your customer already has a Google Nest product, show them how to add the thermostat to their Google account. The thermostat will display a QR code that the customer can quickly scan when prompted by the Google Home app. Point the customer to the Welcome Guide they will receive that can help them understand the features and functions of their new Nest Learning Thermostat. Correct configuration of these features will ensure that the system is performing correctly and the customer is comfortable. Until the thermostat has been added to the customer account, it will only be controllable by manually adjusting the thermostat. It can be used in Heat Mode, Cool Mode, Heat/Cool mode, or set to Off. The setpoint can also be manually adjusted on the thermostat.
Page 32: Installation overview Pro setup steps - Google Home app Add product: Select “Add device” from the Google Home app, choose Nest Learning Thermostat (4th gen), scan the QR code, and select Pro Setup. Connect Pro ID to thermostat: Enter your 6-digit Pro ID. If you do not know it, you can look it up with the link on the screen. Once Pro ID is confirmed, select “Already installed” to skip ahead to equipment setup if the thermostat is already wired and powered on.
Page 33: Installation overview Multifunction wire configuration: Once you’ve confirmed your Pro ID, you need to configure what wires are connected to the thermostat if you have a wire in the O/B, Y2, W2, Star (*), or AQ+ to help the thermostat provide the right equipment selection options in future steps. Language, wire review, and power test: Select the language the thermostat should use, then review connected wires and allow the thermostat to perform a power test.
Page 34: Installation overview Equipment configuration – Heating: You will configure the equipment connected to your wires, starting with the heating wires. For a conventional system, you will choose the heat source and delivery type. If you have a heat pump, you will be asked to configure your primary heat then alternate heating equipment. Equipment configuration – Heat Pump: For heat pump systems with auxiliary heat or alternate heat, you will choose whether to use heat pump balance or advanced heat pump controls, and when the reversing valve should activate.
Page 35: Installation overview includes equipment configuration for the system fan, humidifier or dehumidifier, and ventilation systems. Advanced settings can be adjusted during the pro setup process. These settings cannot be accessed or changed after the pro setup. Consult HVAC equipment manuals and documentation for appropriate settings. Future changes will require a factory reset and reconfiguration of the thermostat.
Page 36: Installation overview Pro setup complete: You will indicate whether the thermostat should begin in heating or cooling mode. The Pro Setup process is complete and the thermostat is ready to be added to the user’s Google Home app. End-user configuration: The thermostat is now ready to be added to the user’s Google Home app. Until it is added to an account and connected to Wi-Fi, it will heat or cool to a single setpoint that can be adjusted using the thermostat manually. The thermostat will show a QR code on the screen when initially pressed that can be scanned when prompted by the Google Home app.
Page 37: Installation overview End-user configuration – continued: When the customer is ready to add the thermostat to their Google Home app, they will start by adding a device. They will need to select “Already Installed” to skip through installation instructions. They will be prompted to connect the thermostat to Wi-Fi enable features and create a starter schedule. Make sure customers understand the features of the thermostat listed in the Key Features section of the document.
Page 38: Installation overview - complex systems How to configure complex systems Heat pump systems Configuring O/B wire – orientation and activation The majority of heat pumps use an “O” orientation, so when setting up a heat pump, this will be the default orientation during configuration. The O or B orientation will be confirmed during Pro Setup, but it can be adjusted at any time after installation. You can choose whether to energize the O/B reversing valve “cyclically” during each heating or cooling cycle or “seasonally.” The “seasonally” option will keep the O/B wire energized when the thermostat is in the cooling mode and the orientation is set to “O” and in the heating mode when the orientation is set to “B.” The Nest Learning Thermostat defaults to energizing seasonally to help reduce wear and tear on the reversing valve, but can be configured to be energized each cycle.
Page 39: Installation overview - complex systems Two-stage heat pumps The Nest Learning Thermostat will automatically recognize your customer’s system as a two-stage heat pump if you’ve connected Y1, Y2, and O/B wires. The thermostat assumes the Y1 wire will be used to activate 1st stage heating and cooling for your heat pump. Using the Pro Setup in the Google Home app, you can then configure the Y2 wire to be used for 2nd stage heating and cooling, 2nd stage cooling only, or 2nd stage heating only. You will also specify the delivery mechanism (such as forced air or radiant).
Page 40: Installation overview - complex systems Duel fuel systems - configuring equipment If there’s an O/B wire and one or more W wires connected to the Nest Learning Thermostat, Pro Setup will ask if the heating system is dual fuel or single fuel. For single fuel, any wires inserted into the W1, W2/AUX connectors will be treated as auxiliary heat that will be used simultaneously with the heat pump when needed. Only one auxiliary heating wire is supported. For dual fuel, any wires inserted into the W1, W2/AUX connectors will be treated as alternate heat that will be used instead of the heat pump when needed. Use Pro Setup to indicate the source (gas, electric, geothermal, etc.) as well as the delivery mechanism (forced air, radiant, etc.) for each of the W wires connected. The Nest Learning Thermostat supports up to two wires for alternate heat; additional alternate heat wires are not supported.
Page 41: Installation overview - complex systems Dual fuel systems activate alternate heat and advanced settings independently from heat pump heating. Settings to activate alternate heat are based on temperature or time. Decide if alternate heat should always be used, never used, or activated below the breakpoint temperature. You will configure the breakpoint temperature unless you choose Never or Always. An additional option for Alternate heat changeover time is available during the Pro Setup process. This setting allows selection of the maximum time the heat pump will run without achieving the target temperature before switching to alternate heat. Select Use custom heat pump settings to set the Alternate heat changeover time.
Page 42: Installation overview - complex systems Advanced heat pump controls – auxiliary heat On the Nest Learning Thermostat (4th gen) there are advanced controls available for heat pump systems. To adjust these settings, you will need to use the Pro Setup process. There is a choice to use Heat Pump Balance or custom heat pump settings during the Pro Setup process. The custom settings are only available when Heat Pump Balance is disabled. Aux upstage timer - how long the thermostat uses heat pump heating to reach the target before engaging auxiliary heat. Aux lockout temperature - if the outdoor temperature is above this temperature, auxiliary heat cannot be used. Droop - how far the indoor temperature must be below the target before auxiliary heat can be used. Minimum delay - the minimum amount of time after the start of a heating cycle before auxiliary heat can be used.
Page 43: Installation overview - complex systems The Nest Learning Thermostat is compatible with most multi-speed fans (up to 3 speeds) on systems that use standard 24V wiring. It will control the fan differently depending on how many fan wires are connected. If your customer has a multi-speed fan with a single wire, the system will control the fan speed, not the thermostat. This means they’ll be able to use the Nest Learning Thermostat to adjust the temperature and turn the fan on or off, but they won’t be able to manually control the fan speed. If there’s more than one fan wire installed, the Nest Learning Thermostat will automatically set the fan speed. Your customer will also be able to select a speed in the Fan menu. When using multiple fan speeds, some HVAC functions will become unavailable.
Page 44: Installation overview for complex systems includes support for whole-home humidifiers and dehumidifiers connected with low voltage wires. Multiple Pro Setup options are available for controlling these devices. Compatible wires are labeled with specific identifiers for humidifiers and dehumidifiers. It's essential to determine if the humidifier or dehumidifier can operate independently or requires heating or cooling. Additional settings may include whether the fan is needed during operation. The Nest Learning Thermostat has powered terminals for connecting humidifiers and dehumidifiers. For a 2-wire setup, connect to AQ+ and AQ-. Consult the installation manual for specific wiring requirements. In dual transformer installations, different wires will use different power sources. The Rc wire powers specific terminals and charges the thermostat, while the Rh wire powers others. Avoid connecting wires from dual transformer systems to the wrong connectors.
Page 45: Installation overview - complex systems Humidifier settings include standalone and heat integrated configurations. Users can activate the system fan and choose a minimum relative humidity to maintain. The Smart Humidification feature can automatically adjust humidity setpoints based on outdoor weather. Quiet Time settings prevent the humidifier from running during specified hours, with a relative humidity range of 10% RH to 60% RH. Dehumidifier settings can also be standalone or A/C integrated. Users must decide on fan operation and equipment activation based on relay status. A/C integrated dehumidifiers utilize the Cool to Dry feature, while standalone units maintain a specific relative humidity between 30% RH and 80% RH. During Pro Setup, Cool to Dry settings can be adjusted, including the overcooling limit, humidity threshold, and minimum indoor temperature for activation. Combined humidifier and dehumidifier settings allow users to set a relative humidity range, with the humidification target needing to be 15% RH below the dehumidification target.
Page 46: Installation overview - standard presets and feature ranges Compressor lockout timer options include 2.5 min (default), 5 min, 7.5 min, and 10 min. Minimum compressor on timer options are 3 min, 5 min (default), 10 min, 15 min, 20 min, 25 min, and 30 min. Minimum conventional heat on timer and heat temperature difference options include 3 min (default), 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min. Cool temperature difference is intelligently set between 0.3° and 1° Fahrenheit (default). Equipment upstage timer includes cool to dry settings of 1 hour for non-heat pump heating and 2 hours for cooling. Overcooling limit options are 1°, 2°, 3° (default), 4°, and 5° Fahrenheit. Humidity threshold options include 55%RH, 60%RH, 65%RH, 70%RH (default), 75%RH, and 80%RH. Minimum indoor temperature options range from 68° to 85° Fahrenheit, with 80°F as the default. Filter reminder frequency options are 250 hrs, 500 hrs (default), 750 hrs, 1000 hrs, 1500 hrs, and 2000 hrs.
Page 47: Installation overview - Standard presets and feature ranges Humidifier and dehumidifier setpoints Dehumidifier: 30%-80% with a default of 55% Humidifier: 10%-60% with a default of 35% Humidifier and dehumidifier: Hum target must be 15% below dehum Heat pump presets and feature ranges Heat pump balance default setting: Balanced Auxiliary heat lockout temperature based on heat pump balance setting Droop: Intelligently set between 0 and 2 degrees Fahrenheit Aux minimum delay and aux upstage timer based on heat pump balance setting Options for aux upstage timer include 30 min, 60 min, and 90 min (default)
Page 48: Installation overview - standard presets and feature ranges Compressor lockout temperature is only available for single fuel heat pump systems. Compressor lockout default temp is -25°F with a range of -25°F to 32°F or always. Dual fuel breakpoint default temp is 30°F with a range of 10°F to 50°F, always or never. Dual fuel changeover timer options include never, 1 hr, 2 hr, 4 hr (default), 8 hr, and 12 hr. Heat default temp is 40°F with a heat range of 35-45. Cool default setting is off with a cool range of 95-105. Eco temps have a heat default temp of 56°F and a heat range of 40°F to 70°F. Cool default temps are 82°F with a cool range of 76°F to 95°F. Settings can be adjusted manually during pro setup.
Page 49: Wiring diagrams for conventional 1-stage heating are provided. Labels for wires include Y1, Y2, G, O/B, Rc, W1, W2/AUX, and C. The heat relay is designated for stage 1. 24VAC common wire is indicated. 24VAC power is sourced from the heating transformer. Installation notes are available for personal or system notes.
Page 50: Wiring diagrams for conventional 2-stage heating provide essential information for installation. Key wire labels include Y1, Y2, G, O/B, Rc, W1, W2/AUX, and C. Y1 and Y2 correspond to heat relays for stage 1 and stage 2, respectively. G is typically used for the fan control. O/B is for reversing valve control in heat pumps. Rc indicates the power from the heating transformer. W1 and W2/AUX are used for auxiliary heat. C is the common wire for 24VAC systems. Install notes are provided for personal or system notes.
Page 51: Wiring diagrams for conventional 3-stage heating are provided. The document includes wire labels and their corresponding functions. Y1, Y2, G, O/B, Rc, W1, W2/AUX, and C are key wire labels. Heat relay stages are identified as Stage 1, Stage 2, and Stage 3. 24VAC common wire is mentioned for the heating system. 24VAC power from the heating transformer is specified. AQ+ and AQ- are included in the wiring details. Installation notes are provided for personal or system notes.
Page 52: Wiring diagrams - conventional 1-stage heating, 1-stage cooling Conventional 1-stage heating, 1-stage cooling Wire label and function Compressor relay (stage 1) Fan relay 24VAC power from cooling transformer Heat relay (stage 1) 24VAC common wire Install notes: use for personal/or system notes
Page 53: Wiring diagrams for conventional 2-stage heating and 1-stage cooling are provided. Key wire labels include Y1 for compressor relay (stage 1) and Y2 for additional cooling stages. The G label corresponds to the fan relay. O/B is used for reversing valve control. Rc indicates the 24VAC power from the cooling transformer. W1 and W2/AUX are for heat relays in stages 1 and 2, respectively. C represents the common wire for 24VAC. Rh is another power connection. Install notes are included for personal or system notes.
Page 54: Wiring diagrams for conventional 2-stage heating and 2-stage cooling are provided. Key wire labels include Y1 for compressor relay stage 1, Y2 for compressor relay stage 2, and G for fan relay. W1 is designated for heat relay stage 1, while W2/AUX is for heat relay stage 2. 24VAC power is supplied from the cooling transformer, with Rc indicating this source. The document includes install notes for personal or system notes.
Page 55: Wiring diagrams for conventional 3-stage heating and 2-stage cooling are provided. Key wire labels include Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, Rh, AQ+, and AQ-. Functions of the wires include compressor relays for stages 1 and 2, fan relay, heat relays for stages 1, 2, and 3, and 24VAC power from the cooling transformer. Installation notes are included for personal or system notes.
Page 56: Wiring diagrams for conventional 1-stage heating and 2-stage cooling are provided. Key wire labels include Y1 for compressor relay stage 1 and Y2 for compressor relay stage 2. G is designated for the fan relay. O/B indicates the reversing valve. Rc is the 24VAC power from the cooling transformer. W1 is for the heat relay stage 1, while W2/AUX is for auxiliary heat. C represents the 24VAC common wire. Rh is another power input. AQ+ and AQ- are also included in the wiring setup. Install notes are provided for personal or system notes.
Page 57: Wiring diagrams for 1-stage heat pump are provided. Key components include Y1 for compressor relay, Y2 for additional stages, and G for fan relay. The O/B terminal is for the heat pump changeover valve. 24VAC power is supplied from the cooling transformer. W1 and W2/AUX are additional heating terminals. C is the common wire for 24VAC. Rh is for heating power. AQ+ and AQ- are used for specific applications. Installation notes are available for personal or system use.
Page 58: Wiring diagrams for 1-stage heat pump with auxiliary heat. 1-stage heat pump with auxiliary heat. Wire label and function details provided. Compressor relay is labeled Y1 for stage 1. Fan relay is labeled G. Heat pump changeover valve is labeled O/B. Auxiliary heat relay is labeled W2/AUX. 24VAC power from cooling transformer is indicated. 24VAC common wire is labeled C. Installation notes for personal or system notes are included.
Page 59: Wiring diagrams - 1-stage heat pump with aux and emergency heat 1-stage heat pump with aux and emergency heat Wire label and function Y1 - Compressor relay (stage 1) Y2 - Fan relay O/B - Heat pump changeover valve W1 - Auxiliary heat relay C - 24VAC common wire E heat Install notes: Use for personal/or system notes
Page 60: Wiring diagrams for a 2-stage heat pump are provided. Key wire labels include Y1 for the compressor relay (stage 1) and Y2 for the compressor relay (stage 2). G is designated for the fan relay. O/B indicates the heat pump changeover valve. Rc represents 24VAC power from the cooling transformer. W1 and W2/AUX are additional wiring connections. C is the 24VAC common wire. Rh is another wire label used in the system. AQ+ and AQ- are also included in the wiring diagram. Install notes are provided for personal or system notes.
Page 61: Wiring diagrams for a 2-stage heat pump with auxiliary heat are provided. Key wire labels include Y1 for the compressor relay (stage 1), Y2 for the compressor relay (stage 2), and G for the fan relay. The O/B label indicates the heat pump changeover valve. W1 and W2/AUX are designated for auxiliary heat relay functions. 24VAC power is sourced from the cooling transformer, with C representing the 24VAC common wire. Install notes are included for personal or system notes.
Page 62: Wiring diagrams for a 2-stage heat pump with auxiliary and emergency heat are provided. Key wire labels include Y1 for compressor relay (stage 1) and Y2 for compressor relay (stage 2). G is designated for the fan relay, while O/B indicates the heat pump changeover valve. Rc represents 24VAC power from the cooling transformer, and W1 and W2/AUX are for auxiliary heat relay. C is the 24VAC common wire, and E Heat is also noted. Install notes are included for personal or system notes.
Page 63: Wiring diagrams for 1-stage heat pump and dual fuel systems are provided. Key wire labels include Y1 for compressor relay, Y2 for additional stages, and G for fan relay. The O/B label indicates the heat pump changeover valve. W1 is designated for the heat relay (stage 1), while W2/AUX is for auxiliary heat. C represents the 24VAC common wire, and Rh is for the heating power. Installation notes are included for personal or system notes.
Page 64: Wiring diagrams for 2-stage heat pump and 1-stage heat. Wire labels and their functions are provided. Compressor relay for stage 1 and stage 2 is included. Fan relay is also part of the wiring diagram. Heat pump changeover valve is indicated. 24VAC power from cooling transformer is specified. Heat relay for stage 1 is included. Auxiliary heat relay is noted. 24VAC common wire is mentioned. Installation notes are provided for personal or system use.
Page 65: Wiring diagrams for 1-stage and 2-stage heat pumps are provided. Key wire labels and their functions include: - Y1: Compressor relay for stage 1 - Y2: Fan relay - O/B: Heat pump changeover valve - W1: Heat relay for stage 1 - W2/AUX: Heat relay for stage 2 - C: 24VAC common wire Installation notes are included for personal or system notes.
Page 66: Wiring diagrams for 2-stage heat pump. Key wire labels and their functions are provided. Y1 is for compressor relay stage 1. Y2 is for compressor relay stage 2. G is for fan relay. O/B is for heat pump changeover valve. W1 is for heat relay stage 1. W2/AUX is for heat relay stage 2. 24VAC power is supplied from the heating transformer. Install notes are included for personal or system notes.
Page 67: Wiring diagrams for 2-stage heat pump and 2-stage heat with emergency heat are provided. Key wire labels include Y1 for compressor relay (stage 1), Y2 for compressor relay (stage 2), and G for fan relay. The O/B wire is for the heat pump changeover valve, while Rc indicates 24VAC power from the heating transformer. W1 and W2/AUX are designated for heat relays (stage 1 and stage 2, respectively). E Heat is also mentioned along with C for the common wire. Install notes are included for personal or system notes.
Page 68: Wiring diagrams for a 2-speed fan are provided. The fan control section outlines the operation of the 2-speed fan. Wire labels indicate the function of each wire in the system. Y1 and Y2 are designated for the first and second speed of the fan. G is used for the fan relay. The 2nd-speed fan relay is included in the wiring setup. O/B indicates the reversing valve for heat pump applications. Rc is connected to the 24VAC power from the heating transformer. W1 and W2/AUX are used for heating stages. C represents the 24VAC common wire.
Page 69: Wiring diagrams for a 3-speed fan are provided. The wire labels indicate the function of each connection. Y1 and Y2 are designated for the first and second-speed fan relays. G is used for the fan relay. O/B is associated with the reversing valve. Rc supplies 24VAC power from the heating transformer. W1 and W2/AUX are for heating control. C is the common wire for 24VAC. The 3rd-speed fan relay is also included in the diagram. Install notes are available for personal or system notes.
Page 70: Wiring diagrams for hum or dehum are provided. The document includes wire labels and their corresponding functions. Key wire functions include Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, Rh, and HUM/DHUM. 24VAC common wire and power from heating transformer are specified. Installation notes are included for personal or system notes.
Page 71: Wiring diagrams for hum or dehum are provided. The document includes a section for wire labels and their functions. Key wire labels include Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, Rh, AQ+, and AQ-. There are specific notes for installation, indicating the use for personal or system notes. 24VAC common wire and power from heating transformer are mentioned. HUM/DEHUM wire 1 and wire 2 are specified.
Page 72: Wiring diagrams for hum or dehum are provided. The document outlines 2-wire hum and 1-wire dehum configurations. Wire labels and their corresponding functions are listed. Key wire functions include Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, DHUM, Rh, AQ+, and AQ-. 24VAC common wire and power from heating transformer are specified. HUM wire configurations are detailed as HUM Wire 1 and HUM Wire 2. Installation notes are included for personal or system notes.
Page 73: Wiring diagrams for hum or dehum are provided. The document includes details on 1-wire hum and 2-wire dehum configurations. Various wire labels and their corresponding functions are listed. Key wire labels include Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, HUM, Rh, AQ+, and AQ-. 24VAC common wire and power from heating transformer are specified. There are notes for installation, intended for personal or system notes.
Page 74: Wiring diagrams for hum or dehum. Overview of ventilation systems. 1-wire ventilation system details. Wire labels and their functions. Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, Rh, and AQ+ / AQ- designations. 24VAC common wire and power from heating transformer. Vent wire 1 specifications. Installation notes for personal or system use.
Page 75: Wiring diagrams for hum or dehum are provided. A 2-wire ventilation system is outlined. Wire labels and their functions are listed. Key wire functions include Y1, Y2, G, O/B, Rc, W1, W2/AUX, C, Rh. 24VAC common wire and power from heating transformer are specified. Vent wire connections AQ+ and AQ- are included. Installation notes are available for personal or system use.
Page 76: Troubleshooting - Handling Unusual Thermostat Wiring When a B or X wire is a common wire, some Trane, American Standard, and York thermostats use B for the common wire. If installing a Nest thermostat to control a heat pump system and the current thermostat has both a B and a C, connect B to the Nest O/B connector and C to the Nest C connector. If the current thermostat has both an O and a B, connect O to the Nest O/B connector and B to Nest’s C connector. If the current thermostat only has a B wire, connect B to the Nest O/B connector. If installing a Nest thermostat to control a conventional system and you see a B wire, connect it to the C connector on the Nest base. Not following the rules for a B wire that is actually a common wire can lead to blowing a fuse on your HVAC controller board and damaging the Nest thermostat. Some heat pump installations may have the auxiliary heat connection labelled as X, W1, or W2. Verify that the X wire on the old thermostat is not a common wire before assuming it is the auxiliary heat. The lockout temperatures for heat pumps are only enforced when the Nest thermostat is connected to Wi-Fi. If Wi-Fi is not enabled, auxiliary heat will come on automatically when it takes longer than expected to reach the current target temperature.
Page 77: Troubleshooting - Power Sharing Understanding Power Sharing The Nest Learning Thermostat can get power from equipment wires even if there is not a common wire through a patented Power Sharing process. The thermostat will draw a small amount of power from the Y and/or W wire when they are active or inactive. The Nest Learning Thermostat has improved power sharing and uses less power to run. In some cases, a common wire is needed to deliver consistent power to the thermostat. Symptoms of inconsistent power delivery may include reduced thermostat battery life and display issues. Users may experience unexpected system behavior, such as turning on or off unexpectedly. A Delayed or Starts in message may appear on the thermostat’s screen. There are four options to solve a power issue: use the Nest Power Connector, use a spare wire as a common wire, add a resistor to an existing wire, or pull a new common wire.
Page 78: Troubleshooting - Power Sharing The preferred voltage of the stat is 3.9V. If the thermostat drops below 3.8V, it will enter a “Power Saver” mode where some features and functions will be disabled. If the voltage drops below 3.6V, the thermostat will disconnect from Wi-Fi. If it drops below 3.7V, other features such as the Wake On Approach of the thermostat will be disabled. Appropriate power readings can be found on the thermostat under Settings > Equipment > Power Info. Iin is the input current limit the thermostat is using now. The letter next to the Iin value indicates the method of power sharing. The value should be above 20mA for full functionality. The thermostat will power share less frequently during the first 5 minutes of a call or heating or cooling when in the A or T mode. PS values are stats for the available methods of power sharing. C indicates maximum current draw on C-wire, verifying C wire functionality. YP or WP is a metric to assess Power Connector presence on Y/W wires.
Page 79: Troubleshooting - Power Solutions If your thermostat has power-related issues, like the battery draining too quickly or Wi-Fi constantly disconnecting, you can typically fix them by connecting a common wire (C wire) or by installing the Nest Power Connector. A Power Connector is needed for each thermostat in a zoned system. The easiest way to solve the problem is by using a spare wire in the thermostat wire as a common wire. Simply connect one end of the unused wire to the common (“C”) terminal in the HVAC controller and the other end to the thermostat’s C terminal. Many Y and W wire circuits that cannot supply enough power can be strengthened by bridging the common terminal at the HVAC equipment to W or Y through a 220-ohm, 5W resistor. In a heat-only system, you need to bridge from common (C) to W. In a HVAC system with a Y wire, you must bridge from common (C) to Y. In a system with both W and Y, you should bridge from common (C) to Y. Replace the thermostat wiring bundle to provide an extra wire to be used as common.
Page 80: Reference Material - “How To” Quick Reference Guides Demonstrate how to use the Nest Learning Thermostat Tips on providing a good customer experience Basic temperature changes Home/Eco mode manual switching Switching between heat/cool modes Changing the temperature schedule Explain key functions of the thermostat Explain rebates and rewards offers in your area Explain Smart Schedule behavior and the initial learning period How to check the power information on the thermostat
Page 81: Reference material - How to quick reference guides Testing the basic operation after installation Use the System Test function in Equipment settings to engage each individual equipment component. If the thermostat is not connected to Wi-Fi, you will need to manually activate equipment. Activate heating and cooling by turning the ring to set the current set point above or below the current ambient temperature. To switch to and from heating and cooling modes, press the ring to bring up the menu and select the Heating and Cooling icon. The Nest Learning Thermostat’s default minimum on-off times for manual temperature adjustments are 2.5 minutes for heat pumps and air conditioning systems. Before the Nest Learning Thermostat activates Time-to-Temperature, second stage heat will turn on when the setpoint is 4°F or greater than the room’s ambient temperature. Auxiliary heat will turn on when the setpoint is 4°F and the outdoor temperature is below 50°F. To test second stage or auxiliary heat at installation, raise the temperature 4°F in heating mode with the auxiliary lockout turned off. Once Time-to-Temperature is activated, the Nest Learning Thermostat will use this feature to manage second stage and auxiliary heat.
Page 82: Reference material - How to quick reference guides To switch to and from heating and cooling modes, follow these steps: Press the thermostat face to bring up the menu. Select the mode icon. Turn the ring to select heat, cool, heat • cool, or off. Press the ring again to confirm the mode selection. Both auxiliary and compressor lockout temperatures can be changed in the equipment settings menu of the Google Home app. The lockout temperatures are only enforced when the Nest Learning Thermostat is connected to Wi-Fi. To access the heat pump section of equipment settings, navigate to the thermostat in the Google Home app. Select settings in the top right. Select Thermostat and scroll down to Equipment. Select and adjust lockout temperatures.
Page 83: Adjust Eco heating and cooling temperatures. These temperatures are set as the final step during the setup interview. To adjust, navigate to the thermostat in the Google Home app, select Settings in the top right, select “Temperature Preferences,” select “Temperature Presets,” and adjust “Eco.” Adjust safety temperatures. No matter the schedule, the Nest Learning Thermostat will never let the home go above or below the safety temperatures. To adjust them, navigate to the thermostat in the Google Home app, select Settings in the top right, select “Temperature Preferences,” and adjust “Safety Temps.”
Page 84: Setting fan speeds for systems with multi-speed fans involves pressing the ring to access the menu, selecting the Fan icon, and choosing the desired system fan speed. You can select Low, Medium, High, or Auto based on your system's wiring. To engage Emergency Heat using the Google Home app, navigate to the thermostat, select Settings, and toggle User Emergency Heat to On. For the thermostat, access the menu, navigate to Settings, select Emergency Heat, and confirm by selecting Yes. To add or verify that your Pro ID is linked to the thermostat, press the thermostat ring to access the Quick View menu and go to Settings. If your Nest Pro information is visible, it is linked to the thermostat. If not linked, you can enter your 6-digit Pro ID found in the Nest Pro dashboard. You may have the option to replace another Nest Pro's contact information if it is already on the thermostat. Customers can view your contact information in the Nest Pro section of the settings menu or in the Google Home app.
Page 85: Reference material - “How to” quick reference guides Pairing Nest with the Google Home app To pair the Nest Learning Thermostat to the Google Home app, follow these steps: Download the Google Home app on your customer’s phone or tablet from the Apple App Store or Google Play. Open the Google Home app and sign in with a Google account. Read and agree to Google’s Terms of Service. Add a device in the Devices tab or the home screen if this is the first device. Select Made by Google Device, then Thermostat and Nest Learning Thermostat (4th gen). Scan the QR code on the thermostat and follow remaining instructions. Factory reset thermostat You need to factory reset the thermostat if the wiring has changed or Advanced Settings available during Pro Setup need to be adjusted. Follow these steps to access the Factory Reset settings: Press the ring to bring up the menu. Turn the ring and select Settings. Turn the ring and select Factory Reset. Re-configure Wi-Fi network Follow these steps to update the Wi-Fi network: Navigate to Settings tab of the thermostat. Select Device Information. Choose Wi-Fi, then press “OK” to begin changing network. Disconnect thermostat from account Follow these steps to disconnect the thermostat from an account: Press the ring to bring up the menu. Turn the ring and select Settings. Turn the ring and select Account. Confirm and disconnect the account.
Page 86: Wiring error quick reference guide If the Nest Learning Thermostat senses a problem with the wiring, you’ll receive an “E” error. These errors must be fixed before setup can continue. “N” errors are not as critical and setup will continue, but certain features may not work. “E” errors related to wires not being detected can be the result of a wire not being fully inserted into the connector or terminal. Ensure that all wires are fully inserted and the connector buttons are in the down position before performing additional troubleshooting. These errors may change with future software updates. Power wire Rc detected. Not connected to equipment. The Nest Learning Thermostat isn’t electrically detecting the Rc wire, but one is connected to the Nest base. Power wire Rh detected. Not connected to equipment. No power to W1 wire detected. No power to Y1 wire detected.
Page 87: Wiring error quick reference guide Important note: These errors may change with future software updates. Error # N408: No power to Y2 wire detected. The Nest Learning Thermostat isn’t electrically detecting the Y2 wire, but one is connected to the Nest base. Error # N409: No power to (star) wire detected. The Nest Learning Thermostat isn’t electrically detecting the * wire, but one is connected to the Nest base. Error # N413: A C wire or Nest Power Connector is recommended for your thermostat. There is insufficient power from Y1 and W1 to power the thermostat. Error # N414: Low power to C wire. The Nest Learning Thermostat detected abnormally low power available from the C wire. Error # N415: No power to AQ+ wire detected. AQ- requires AQ+. The Nest Learning Thermostat isn’t electrically detecting the AQ+ wire, but one is connected to the Nest base. Error E421: E (emergency heat) wire without O/B wire. The Nest Learning Thermostat is physically detecting a * (E) wire but not an O/B wire. Error E443: G2 and O/B wire conflict. The Nest Learning Thermostat has detected a G2 (fan) wire in the Y2 connector, and a wire in the O/B connector.
Page 88: Wiring error quick reference guide – continued Important note: These errors may change with future software updates. Error # E440: G2 wire detected. Remove W2/AUX wire. The Nest Learning Thermostat is physically detecting a wire in the W1 connector, a wire in the AUX/W2 connector, and a G2 (fan) wire in the Y2 connector. Error # E439: G2 detected. G1 wire is also required. The Nest Learning Thermostat is physically detecting a G2 (fan) wire in the Y2 connector, but it’s not detecting a wire in the G connector. Error # E442: G3 wire detected. G1 and G2 also required. The Nest Learning Thermostat is physically detecting a G3 (fan) wire in the connector, but it isn’t detecting a G2 (fan) wire in the Y2 connector or a wire in the G connector. Error # E419: Y2 wire without Y1 wire. AQ and star wire conflict. The Nest Learning Thermostat is physically detecting a Y2 wire, but not a Y1 wire that is required for 2-stage conventional cooling systems or 2-stage heat pumps. Error # E450: The Nest Learning Thermostat has detected a wire in the AQ connector and a wire in the * connector, both of which are configured as humidifiers (or dehumidifiers). Error # E448: No system power. The Nest Learning Thermostat does not detect power. If a C wire is present, then power is not detected on the C wire.
Page 89: Troubleshooting Quick Reference Guide Symptom: Nest doesn’t turn on after installation What’s going on: The internal battery is low and needs to charge. If you leave it where it is, it will slowly charge and eventually turn on. Solid Amber light If you have a USB-C cable and wall charger, you can charge it quicker over USB. Symptom: The power was never turned back on. Use normal electrical troubleshooting techniques to isolate the issue to either the fuse/breaker box or a fuse on the HVAC controller board. Unit seems to be running backwards (heat pump) If it is heating when it is supposed to be cooling and vice versa, the orientation of the heat pump is probably incorrect. Follow these steps to change the heat pump orientation: Navigate to the thermostat in the Google Home app. Select settings in the top right. Select “Thermostat.” Scroll down to “Equipment.” Select Heat Pump. Select O wire or B Wire under Heat Pump Wire. Symptom: Forgot lock code Customer has forgotten the lock code to their Nest Learning Thermostat. The Nest Learning Thermostat can be remotely unlocked by logging onto the Google Home app paired with their device.
Page 90: Troubleshooting Quick Reference Guide Symptom: What’s going on: Steps to fix: Fan doesn’t come on Check the wiring to make sure the wires are in the right place and the wire tips are straight and fully inserted into the connectors. Turn off HVAC breakers and pull out the Rh and the G wires. Carefully hold them together with the copper ends touching for 10-20 seconds. If the fan turns on, there may be a hardware issue with the device. If the fan does not turn on, there is an issue with the heating and cooling system unrelated to the Nest thermostat.
Page 91: Glossary Airwave Google Assistant Google Home App Heat pump balance Home/Away assist System health monitor Interactive troubleshooter tool Power sharing Auto changeover (heat/cool mode) Nest app