Filter
Top Products
518-92178N page 2 of 2
Push button will not remain in the depressed position after
engine startup (wired according to Figure 2).
• Be sure oil pressure is adequate to raise pointer past SWICHGAGE
®
contact. (Not necessary if oil pressure SWICHGAGE
®
is equipped with
push button lockout.)
• Visually check wiring for loose connections, frayed wiring, etc. on all
terminals and within switch loop circuit.
• Check 14 amp fuse connected to “B” terminal.
• Check for good ground on “G” terminal.
• Disconnect switch loop circuit from “SW1” and “SW2” terminals. Place
a temporary jumper between SW1 and SW2 and restart engine. If the
push button stays in with engine running, the 518PH/518APH is not the
problem. This indicates either an open circuit, unwanted ground, or too
high resistance in switch loop circuit wiring between “SW1” and “SW2”.
• Verify continuity by performing the following:
1. Disconnect switch loop circuit from “SW1” and “SW2” terminals.
2. Remove power from “B” terminal.
3. Use an ohmmeter to check for “good continuity” (25 ohms or less)
through switch loop circuit. If good continuity is indicated, proceed
to Step 4.
4. Adjust SWICHGAGE
®
contact away from pointer. Check continuity
between one end of loop circuit, “SW1 or “SW2” and ground. Good
continuity (25 ohms or less) indicates an unwanted ground in loop cir-
cuit such as a terminal rotating against the mounting panel. Remove
ground, restore loop circuit connections to “SW1” and “SW2”.
5. Reconnect power to “B” terminal and restart engine.
6. Using an ohmmeter, check resistance between one end of the loop
circuit to the other. Resistance should not exceed 25 ohms. If resis-
tance is too high, check for loose connections in loop circuit.
Otherwise select larger size wire for loop circuit.
Engine fails to shutdown when contacts close on one-wire to
ground SWICHGAGE
®
controls (wired according to Figure 1).
With engine running, jumper “SW1” to “G” terminal. If switch trips and
engine shuts down, trouble could be SWICHGAGE
®
contacts not making
contact, lack of good case ground on SWICHGAGE
®
, or broken/cut wire.
Lack of case ground on SWICHGAGE
®
.
Verify that mounting bracket on the SWICHGAGE
®
has broken through
the panel paint and has made good contact with bare metal. If good con-
tact has not been made, tighten mounting stud nuts accordingly.
Failure of contacts on SWICHGAGE
®
to make contact.
Adjust contacts back and forth against the pointer to give a wiping and
cleaning action on contacts. If this does not correct the problem, replace
SWICHGAGE
®
.
TROUBLESHOOTING
TYPICAL WIRING DIAGRAMS
G NO
R
NC
SW1 SW2
B
“Energized”
To Shutdown
Solenoid Operator
*
“De-energized”
To Shutdown
Fuel Valve
“De-energized”
To Shutdown
Ignition Coil
Normally Open
SWICHGAGE
®
Instruments
Ammeter
14 Amp
In-Line Fuse
*
* In-Line Fuse should be removed on “energized” to shutdown configurations.
Ignition
Switch
Battery
518PH / 518APH
Normally
Closed
Switches
**
**
Applies to 518APH model.
G NO
R
NC
SW1 SW2
B
“De-energized”
To Shutdown
Fuel Valve
or
Solenoid
Operator
“De-energized”
To Shutdown
Ignition Coil
Normally Open
SWICHGAGE
®
Instruments
Ammeter
Ignition
Switch
Battery
518PH / 518APH
14 Amp
In-Line Fuse
*
“Energized”
To Shutdown
Solenoid Operator
*
*
In-Line Fuse should be removed on “energized” to shutdown configurations.
**
**
Applies to 518APH model.
Figure 1 shows a jumper installed between “SW1 and “SW2”.
SWICHGAGE
®
instruments are normally open. This is not a
Closed Loop™ circuit.
Figure 2 shows a Closed Loop™ circuit with normally open Murphy
SWICHGAGE
®
instruments and Normally Closed switches (alignment
and “V” belt switches, etc.).
Figure 2
Figure 1
CONTROL SYSTEMS & SERVICES DIVISION
P.O. Box 1819; Rosenberg, Texas 77471; USA
+1 281 633 4500 fax+1 281 633 4588
e-mailsales@fwmurphy.com
MURPHY DE MEXICO, S.A. DE C.V.
Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje
San Luis Potosí, S.L.P.; México 78384
+52 444 8206264 fax +52 444 8206336
Villahermosa Office +52 993 3162117
e-mailventas@murphymex.com.mx
www.murphymex.com.mx
FRANK W. MURPHY, LTD.
Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.
+44 1722 410055 fax+44 1722 410088
e-mailsales@fwmurphy.co.uk
www.fwmurphy.co.uk
MURPHY SWITCH OF CALIFORNIA
41343 12th Street West
Palmdale, California 93551-1442; USA
+1 661 272 4700 fax+1 661 947 7570
e-mailsales@murphyswitch.com
www.murphyswitch.com
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.
MACQUARRIE CORPORATION
1620 Hume Highway
Campbellfield, Vic 3061; Australia
+61 3 9358 5555 fax+61 3 9358 5558
e-mailmurphy@macquarrie.com.au
FW Murphy
P.O. Box 470248
Tulsa, Oklahoma 74147 USA
+1 918 317 4100
fax +1 918 317 4266
e-mail sales@fwmurphy.com
www.fwmurphy.com
R
E
G
I
S
T
E
R
E
D
USA–ISO 9001:2000 FM 28221
UK–ISO 9001:2000 FM 29422
Printed in U.S.A.