Honeywell L641 Surface Contact Thermostat Instructions

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L641  

SURFACE CONTACT  

THERMOSTAT  

PRODUCT DATA  

FEATURES  

 Version available for use as a cylinder thermostat in  

domestic hot water installations  

 Version available for use as a pipe thermostat in fan-  

coil applications  

 Version available for use as a pipe thermostat in frost  

protection applications  

 Version available for use as a pipe thermostat to limit  

the supply water temperature in underfloor heating  

and solid fuel systems  

 The S.P.D.T. switching action is accomplished by a  

snap-action MICRO SWITCH which is actuated by a  

bimetal temperature sensing element  

 The desired temperature control point is set by the  

clearly scaled temperature selector on the front cover  

 Wiring terminals are easily accessible  

 Tamperproof temperature setting (L641B)  

 Screwdriver slot temperature setting, with optional  

DESCRIPTION  

manual setting knob supplied (L641A)  

The L641 is a surface contact thermostat designed to sense  

the water temperature in storage cylinders and water pipes,  

and to provide temperature control, temperature limiting, and  

temperature feedback functions.  

 CE approved  

L641A mounts directly onto domestic hot water cylinders and  

can be wired to directly switch a wet central heating  

circulating pump, or boiler, or to operate spring return and  

motor open/motor close zone valves.  

L641B mounts directly onto a pipe and can provide high limit,  

low limit or frost protection in wet central heating systems or  

automatic summer/winter changeover in XE70 fan-coil control  

systems.  

l641-en0r8444-uk07r0515  

https://manual-hub.com/  

VIEW FULL SCREEN PDF MANUAL

General	Details
Name	Honeywell L641 Surface Contact Thermostat Instructions
Make	Honeywell
Language	English
Filetype	PDF (Download)
File size	0.15 MB

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• ALL THERMOSTAT INSTRUCTIONS & USER MANUALS
• Honeywell

Honeywell L641 Surface Contact Thermostat Instructions Overview

Summary of Contents

• Page 1: Surface contact thermostat designed to sense water temperature in storage cylinders and water pipes. Version available for use as a cylinder thermostat in domestic hot water installations. Version available for use as a pipe thermostat in fan-coil applications. Version available for use as a pipe thermostat in frost protection applications. Version available for use as a pipe thermostat to limit supply water temperature in underfloor heating and solid fuel systems. The S.P.D.T. switching action is accomplished by a snap-action micro switch actuated by a bimetal temperature sensing element. The desired temperature control point is set by the clearly scaled temperature selector on the front cover. Wiring terminals are easily accessible. Tamperproof temperature setting (L641B) and screwdriver slot temperature setting with optional manual setting knob supplied (L641A). CE approved.
• Page 2: L641 surface contact thermostat Specifications Supply voltage: 230 V~, 50...60 Hz Switch action: S.P.D.T. Type 1CL Switch rating: 4(2) A, 230 V~ Model: L641A1039, L641B1004, L641B1012 Temperature setting range: Min, 40 to 80 °C; Min, 10 to 40 °C; 50 to 95 °C Mounting: L641A mounts directly onto cylinder using fixing strap provided; L641B mounts directly onto pipes using fixing springs provided Dimensions: 44 x 79 x 54mm (1.73 x 3.11 x 2.13) Approvals: L641 is CE, RoHs and WEEE compliant Important: The installer must be a trained service engineer; Disconnect the power supply before beginning installation Installation: The L641A cylinder thermostat should be mounted 1/4 to 1/3 of the way from the bottom of the domestic hot water cylinder.
• Page 3: L641 surface contact thermostat Application High limit underfloor heating systems Low limit frost protection DHW storage tanks/cylinders High limit solid fuel systems Fan-coil unit summer/winter changeover for 2-pipe units The L641A should be mounted 1/4 to 1/3 of the way from the bottom of the cylinder. The L641B should be mounted less than 0.6 m (2') from the boiler. Water temperature sensing and control.
• Page 4: L641 surface contact thermostat Summer / winter changeover for 2-pipe fan-coil units Wiring diagrams High limit Timer Heating load Low limit (frost protection) Automatic summer/winter changeover XE70 series Typical wiring Fan coil unit