Honeywell C645A-E User Manual

Copyright © 1995 Honeywell Inc. • All Rights Reserved
PRODUCT DATA
C645A-E
Pressure Switches
FEATURES
• C645A,B models are for use on natural gas, LP gas,
or air.
• C645B1047 includes a scaleplate stop to meet
American Gas Association (AGA) requirements for
gas-fired boilers with inputs over 2-1/2 million Btuh.
• C645C,D models are for use on air only.
• C645E for use with distillate fuel oil.
• Spring-loaded diaphragm actuates snap-acting
Micro Switch.
• Switch can be wired to turn on alarm.
• C645A,C and D models break control circuit on
pressure fall.
• C645B models break control circuit on pressure rise.
• Lockout and manual reset optional in A and C models.
• Removable, zinc-plated cover protects scaleplate and
adjusting screw.
• Lockout models have external manual reset lever.
• Pipe tappings allow selection of positive pressure,
differential-pressure, or venting connections.
• Optional switch position indicator available.
• Models of C645A,B available with cover window for
setpoint visibility.
• Buna-N fiber-reinforced material for increased control
diaphragm strength.
• Two seal-off diaphragms for added reliability.
60-2159-8
C645A,B with Window
GENERAL
The C645 pressure switches are safety devices used in
positive-pressure or differential-pressure systems to sense
gas or air pressure changes.
C645A,B,D,E
C645C
Contents
General ............................................................................... 1
Features .............................................................................. 1
Specifications ...................................................................... 2
Ordering Information ........................................................... 2
Installation ........................................................................... 4
Settings and Adjustments ................................................... 6
Operation and Checkout ..................................................... 7

Honeywell C645A-E Specifications

General

Brand	Honeywell
Model	C645A-E
Category	Switch
Language	English

Summary

General

Features

Specifications

Models

Details model variations and their characteristics.

Switch Ratings

Lists electrical current ratings for different switch models.

Alternate Electrical Ratings

Special ratings for use with Honeywell programmers.

Ordering Information

Installation

Mounting

Instructions and considerations for physically mounting the pressure switch.

Settings and Adjustments

Pressure Setpoint Adjustment

Guide on how to adjust the pressure setpoint using the adjustment screw.

C645B1047 Scaleplate Stop Adjustment

Procedure for adjusting the scaleplate stop on specific models.

Operation and Checkout

Manual Resetting

How to manually reset lockout models after pressure changes.

Checkout

Procedures for verifying correct operation after installation.

C645C,D—Air Switch Only

Specific checkout steps for C645C and C645D air switches.

C645E1002—Distillate Fuel Oil Switch

Checkout steps for the C645E1002 fuel oil pressure switch.