sect. 05
00-02-0162
rev. 2016/07/26
In order to consistently bring you the highest quality, full-featured products, we reserve the right to change our specifications and designs at any time. MURPHY products and the Murphy
logo are registered and/or common law trademarks of Enovation Controls, LLC. This document, including textual matter and illustrations, is copyright protected by Enovation Controls, LLC,
with all rights reserved. (c) 2016 Enovation Controls, LLC. A copy of the warranty may be viewed or printed by going to www.fwmurphy.com/warranty.
Installation Instructions
Pressure and Vacuum Dial Murphygage
®
and Swichgage
®
Instruments
20, 25, A20 and A25 Series, 2 and 2-1/2 in. (51 and 64 mm) Dial Sizes
The 2 and 2-1/2 in. (51 and 64 mm) dial size Murphygage and
Swichgage instruments are diaphragm-actuated, pressure or vacuum
gages with a 1/8-27 NPTM pressure port connection (2 pressure
ports for differential pressure models).
Models with face-adjustable contact(s) are rated for 2 A @ 30 V (pilot
duty). If the gage case is steel (20P, 25P, 20DP, 25DP etc.), the ground
path for the contact circuit is through the case. Therefore, the case
must be installed in the ground plane of the electrical power supply.
If the case is polycarbonate (A20P, A20DP, A25P, A25DP etc.), the
ground path is isolated and is made through the C or P terminals on
the back of the gage case (C for A20 models; P for A25 models).
Models 20PE, 25PE, A20PE, A25PE etc. have a snap-acting switch
instead of the face adjustable pointer type contact. Electrical rating
is 3 A @ 30 VDC, 4 A @ 125 VAC. Reset differential for the switch is
approximately 10% of the scale.
NOTE:
Select a scale so your normal operating pressure is in the
upper middle of the scale.
Typical Mounting Dimensions
. . . . . . . . . .
Alarm Before Shutdown Models
The models 20PABS, A20PABS, 25PABS and A25PABS feature a
front limit contact for equipment shutdown and an internal SPDT
snap-switch for Alarm Before Shutdown. When the low side (preset
point) of the snap-switch trips, the N.C. terminal completes a circuit
to activate an alarm. A continued decrease in pressure will complete
the shut-down circuit. An increase in pressure of approximately 10%
of scale is necessary before the snap-switch (alarm) will reset and
open the circuit.
Description
Typical Tattletale
®
Magnetic Switch
Murphy by Enovation Controls manufactures several patented
Magnetic Switches for protection of the pilot-duty Swichgage
contacts and to ensure positive shutdown of equipment. There are
magnetic switches for CD ignition, Magneto, Battery systems and
electric motor-driven equipment. Tattletale annunciators show the
cause of shutdown. The first one to trip will lockout all other Tattletale
annunciators. Be sure the type of magnetic switch or Tattletale
annunciator matches the power source used to trip it.
NOTE:
At equipment startup (for models not having a built-in time
delay), the reset button must be held in until normal operation occurs
or an external time delay may be used. Instructions are packed with
each Magnetic Switch or Tattletale annunciator.
20 Series
A20 Series
25 Series
A25 Series
A
2-7/32 (56)
2-9/16 (65)
2-1/8 (54)
1-51/64 (46)
B
1-5/16 (33)
1-1/4 (32)
1-3/8 (35)
1-27/64 (36)
C
2-15/64 (57)
2-1/4 (57)
3-1/8 (79)
2-29/32 (74)
D
2-1/16 (53)
2-1/16 (53)
2-11/16 (68)
2-11/16 (68)
The dimensions are in inches and (millimeters).
NOTE:
20/25 Series: 18 AWG pigtails. A20/A25 series: #4/#6 screws.
Before beginning installation of this Murphy product:
•
Disconnect all electrical power to the machine
•
Make sure the machine cannot operate during installation
•
Follow all safety warnings of machine manufacture
Please read the following instructions and visually inspect product for shipping damage before installation.
When properly used, the Swichgage instruments, magnetic switches
and shut-down or alarm devices are effective tools in any preventive
maintenance program. For optimum performance, check these tools
periodically:
3
Look for frozen pointers, kinked/worn tubing, broken wiring or
loose connections.
3
Operate the contacts and watch for expected results.
3
Replace damaged/worn parts; clean/repair as necessary. Check
for correct/complete wiring, unbroken insulation and no accidental
grounds.
3
Do not run shut-down wires with ignition wiring.
3
Check all tubing and connections for leaks.
Check List
Panel Mounting
1. Remove the mounting clamp
and fasteners.
2. Insert the gage from the front
side of the panel.
3. Reinstall the mounting clamp
and fasteners. Do NOT over-
tighten.
All models can be installed in a panel from 0.032 to 0.250 in. (1 to 6
mm) thick.
IMPORTANT
: Mount the magnetic switches and valves
upright to prevent moisture collection.
Certain dangers to human safety and to
equipment may occur if some equipment is
stopped without pre-warning.
It is recommended that monitored functions be limited to alarm
only or to alarm before shutdown.
Products covered by this bulletin comply with EMC Council directive 89/336/
EEC regarding electromagnetic compatibility except as noted.
To order call 1-800-548-1191 or visit www.partdeal.com - [email protected]
