PRODUCT DATA

Copyright © 1995 Honeywell Inc. • All Rights Reserved
C437D,E,F,G,H,J,K and C637B GasPressure Switches

FEATURES

•C437 models have direct- and reverse-acting (spst)
switching; C637B has single-pole, double-throw (spdt)
switching.
•Pressure ranges: 1/2 to 5-1/2 in. of water (10 to 140mm
of water, or 0.1 to 1.4 kPa); 1 to 26 in. of water (50 to
700 mm of water, or 0.5 to 7 kPa); 1/2 to 5 psi (300 to
3500 mm of water, or 3 to 35 kPa); 1 to 10 psi (500 to
7000 mm of water, or 5 to 70kPa).
•Models intended for lockout applications must be
manually reset before resuming operation.
•Trip-free mechanism on manual reset models ensures
that the limit function of the switch cannot be defeated
by jamming the reset lever.
•External manual reset button on side of lockout
models.
•Enclosed setting impedes tampering and provides
dust-resistant operation.
•Buna-N fiber-reinforced material for increased
strength of control diaphragm.
•Two Buna-N fiber-reinforced seal-off diaphragms for
added reliability.
•Clear glass cover allows observation of interior
mechanism to aid setting and checkout.
•Mercury switch provides visual indication of switch
position.
•Heavy die-cast case increases durability and
resistance to corrosion.
•Main control diaphragm completely enclosed a leak-
proof chamber can be vented to a safe area.
•Models with a pressure range of 1 to 26 in. of water
(50 to 700 mm of water, or 0.5 to 7 kPa) have a
restrictive orifice in the inlet pressure channel to
compensate for momentary surges in gas pressure.
•Field-addable orifices of various sizes are available.
•Models available with rainproof, dustproof, sleet- and
ice-resistant enclosure; meets NEMA 3R specification.

Contents

General ............................................................................... 1
Features.............................................................................. 1
Specifications...................................................................... 2
Ordering Information........................................................... 2
Recycling Notice ................................................................. 4
Installation........................................................................... 4
Setting and Checkout.......................................................... 6

GENERAL

The C437 and C637 Gas Pressure Switches are pressure-
actuated switching devices used in industrial gas system
applications for safety shutoff, pressure control, and
differential-pressure control.
60-2320-9