PRODUCT DATA
Copyright © 1995 Honeywell Inc. • All Rights Reserved
C437D,E,F,G,H,J,K and C637B Gas
Pressure 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 140 mm
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 70 kPa).
• 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