Murphy 25PWC Switch User Manual


 
PWC-94125B
Revised 02-97
Catalog Section 05
(00-02-0033)
Low Pressure SWICHGAGE
®
20PWC, 25PWC and A25PWC Series
For Monitoring Fuel Gas Pressure or
Engine Crankcase Pressure
Actuate Alarm or Shut Down System
When Abnormal Pressure Occurs
Combination Indicating Gage and
Critical Limit Switch
Description
The PWC Series SWICHGAGE
®
is excellent
for low pressure applications such as engine
shutdown when fuel gas pressure falls to low
level. Suitable for both natural gas or
methane–these SWICHGAGE
®
instruments
can also be used to monitor high engine
crankcase pressure (order option “H”).
The 20 and 25 series gage mechanism is
enclosed in a steel case coated to resist cor-
rosion. The 20 series has a 2 inch (51 mm)
diameter dial. The 25 series has a 2-1/2 in.
(64 mm) diameter dial.
The A25 series gage has a sealed polycar-
bonate case and includes a 2-1/2 in. (64 mm)
diameter dial.
All gages feature a polycarbonate, break-
resistant lens and a polished, stainless steel
bezel to help protect these rugged, built-to-
last instruments.
The PWC series is available in either the
SWICHGAGE
®
version with adjustable high
and/or low switch contact(s) or in the indi-
cating MURPHYGAGE
®
configuration.
The SWICHGAGE
®
incorporates an accurate
direct-reading gage with a limit switch (low
contact for fuel gas pressure; high contact for
crankcase pressure) that can be adjusted from
the front of the gage. The switch can be used to
activate alarms and/or shut down equipment.
Specifications
Ranges:
20PWC Series
0-4 in. H
2
O; single scale
0-10 in. H
2
O; single scale
0-20 in. H
2
O / 0-51 cm; dual scale
0-30 in. H
2
O / 0-76 cm; dual scale
0-50 in. H
2
O / 0-127 cm; dual scale
25PWC and A25PWC Series
0-30 in. H
2
O / 0-76 cm; dual scale
0-50 in. H
2
O / 0-127 cm; dual scale
Contact Rating: 2 A @ 30 Volts AC/DC.
Accuracy: ±3% first and last 1/3 of scale,
±2% middle 1/3 of scale.
Maximum Pressure: 2 x scale.
Process Connection: 1/8-27 NPTM brass.
Dial: White on black; single scale (inches)
and dual scale (inches/centimeters).
Limit Switch Adjustment: 1/16 hex wrench.
Mounting Hole: 2-1/16 in. (52 mm).
Bezel: Polished stainless steel.
Lens: Polycarbonate.
Mounting Studs: 10-32 UNF.
Case:
20PWC and 25PWC Series: Plated steel.
A25PWC Series: Polycarbonate.
Wiring (SWICHGAGE
®
Only):
20PWC Series: One point,
#6 terminal block, case ground.
25PWC Series: Wire lead; 18 AWG x
12 in. (1.0 mm
2
x 305 mm).
A25PWC Series: #6 terminal block.
Mounting Clamp: Plated steel.
Shipping Weight:
20PWC Series: 9 oz. (279 g).
25PWC and A25PWC Series:
11 oz. (342 kg).
Shipping Dimensions:
20PWC Series:
3 x 2-3/4 x 2-3/4 in. (76 x 70 x 70 mm).
25PWC and A25PWC Series:
4-3/4 x 4-3/4 x 2-3/4 in. (121 x 121 x 70 mm).
Warranty
A two-year limited warranty on materials and
workmanship is given with this Murphy product.
Details are available on request and are packed
with each unit.
2 and 2-1/2 in. (51 and 64 mm) Dial
20PWC-10
®
FRANK W.
MFR.
PHASED-OUT