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C437D,E,F,G,H,J,K AND C637B GAS PRESSURE SWITCHES
60-2320—9
3
Switch:
Mercury switch (C437F,J and K have two spst switches in one mercury bulb).
Differentials:
Fixed, nominal; measured at pressure indicated:
a
in. = inches of water; mm = millimeters of water.
b
Restrictive orifice in inlet pressure channel to compensate for momentary surges in gas pressure.
c
Not available for C437J.
d
Subtractive models: switching action occurs on pressure rise to the setpoint.
e
Not available for C437K.
f
Additive models: switching action occurs on pressure fall to the setpoint.
Pressure Ranges (Scale Range):
Specify one:
1/2 to 5-1/2 inches of water (10 to 140 mm of water, or
0.1 to 1.4 kPa).
1 to 26 inches of water (50 to 700 mm of water, or 0.5 to
7 kPa).
1/2 to 5 lb per sq in. (300 to 3500 mm of water, or 3 to
35 kPa).
1 to 10 lb per sq in. (500 to 7000 mm of water, or 5 to
70 kPa).
Maximum Sustained Operating Pressure:
Minimum Temperature:
32°F (0°C).
Approvals:
Underwriters Laboratories Inc. Listed: File No. MP2168,
Guide No. MFHX.
Canadian Standards Association Certified: File No. 1620,
Guide No. 380-W-1.16.
Factory Mutual Approved: Report No. 13031-S5 and
19291.
Replacement Parts:
106729 Cover Glass, 6 in. (152.4 mm) diameter.
139870A Cover Glass, for rainproof enclosures.
106747 Cover Retaining Ring, for models manufactured
before 1973.
118733-21 Retaining Clip, for models manufactured since
1975.
Accessories:
4074BWK Bag Assembly: Contains two 137755 Mounting
Brackets and four self-tapping screws: for surface
mounting (standard on C437G and H). Mounting
brackets are shown by dashed lines in Fig. 1.
Field-addable Orifices:
124674: 0.011 in. (0.28 mm) diameter.
122160: 0.018 in. (0.46 mm) diameter.
Pressure Range
a
Model
1/2 to 5-1/2 in.
(10-140 mm, or
0.1-1.4 kPa)
Differential Measured
at 1/2 in.
1 to 26 in.
b
(50-700 mm, or
0.5-7 kPa)
differential
measured at 15 in.
1/2 to 5 psi
(300-3500 mm, or
3-35 kPa) differential
measurement at
midscale
1 to 10 psi
(500-7000 mm,
or 5-70 kPa)
differential
measurement
Numbers
in. mm kPa in. mm kPa psi mm kPa psi mm kPa Type
a
C437D,J — — — 1-3/4 44.5 0.44 1/2 352 3.45 1
c
703
c
6.89
c
Subtractive
d
C437E,F,H,K 0.25
e
6.4
e
0.06
e
1-1/4 31.8 0.31 1/4 176 1.72 1/2
e
352
e
3.45
e
Additive
f
C637B 0.15 3.8 0.04
C437G — — — 1-1/4 31.8 0.31 1/4 176 1.72 1/2 352 3.45 Subtractive
Maximum Pressure
Pressure Range psi kPa
1/2 to 5-1/2 in. of water 3.0 20.7
1 to 26 in. of water 5.0 34.5
1/2 to 5 psi 15.0 103.4
1 to 10 psi 30.0 206.8
Pipe Connections:
Main or High Pressure: 1/2 in. NPT, female.
Vent or Low Pressure: 1/8 in. NPT, female.
Electrical Wiring: Hole tapped for 1/2 in. conduit.
Maximum Ambient Temperature:
125°F (52°C).