Murphy EL150EX User Manual

L-7758N page 1 of 4

Installation Instructions for L150, EL150K1, and
EL150EX Level SWICHGAGE

®

s for Engine Liquids

L-7758N

Revised 06-00

Section 15

(00-02-0171)

Description

The L150, EL150K1 and EL150EX Level SWICHGAGE

®

instruments are
a combination liquid level gauge and low limit switch. Each unit includes a
float chamber, an indicating pointer, a dial, and a low level contact. When
properly installed and maintained, the float operates the pointer which, in
turn, both indicates level during normal operation, and closes a switching
circuit if the level falls to the low-limit set point.

Applications

The primary use of these level SWICHGAGE

®

instruments is for engine
cooling systems, surge or expansion tanks, condenser radiator or vapor
phase systems, whether pressurized or atmospheric. These instruments can
also be used to monitor lube oil, hydraulic fluid or diesel fuel reservoirs and
activate alarms and/or shutdown at a predetermined minimum level.
These instruments are built for low pressure systems.

Cold Weather Warning

BEFORE FREEZING WEATHER COMES, CHECK TO BE
SURE YOUR L150 OR EL150 SERIES COOLANT LEVEL

SWICHGAGE®IS FILLED WITH ANTIFREEZE SOLUTION
THE SAME AS YOUR ENGINE BLOCK AND RADIATOR. On many
engines, such as condenser radiator systems, the coolant in your level
SWICHGAGE®remains static until the level falls to drain point. When
‘winterizing’ it’s a good idea to make certain all water drains from your level
SWICHGAGE

®

, to check against clogged connections, and then BE SURE IT
REFILLS WITH ANTIFREEZE. FAILURE TO OBSERVE THIS
PRECAUTION COULD RESULT IN EQUIPMENT DAMAGE.

Please read the following instructions before installing. A visual inspection for damage during shipping is recommended

before mounting. It is your responsibility to have a qualified person install the unit.

GENERAL INFORMATION

L150 EL150EX

Float

• Brass

••

• Stainless Steel (AISI 304)

•

Electrical Connection

• (1) 16 AWG x 24 in. (1.5 mm2x 610 mm)

•

with terminals.

• (3) 18 AWG x 14 in. (1.0 mm2x 356 mm)

•

• Terminal Block

•

CSA Listed for Hazardous Location:

Class I, Division 1, Groups C & D.

•

O-Rings: Saturated Nitrile, suitable for coolant or

hydrocarbons. Maximum temperature

•• •

250°F (120°C)

Cover Gasket

• Neo-cork

••

• Buna

•

Case

• Die cast aluminum, polyurethane coated

••

• Sand cast aluminum, painted.

•

Specifications

Lens

• Polycarbonate

••

• Tempered glass

•

Contact Rating

• Pilot duty 2 A @ 30 VAC/DC resistive SPST

•

• SPDT rated 10 A @ 125 VAC; 0.5 A @ 125 VDC;
10 A @ 30 VDC

••

Maximum Working Pressure:

•• •

25 psi (172 kPa) [1.72 bar]

Vent Tube: 1/4 x 5 in. (6 x 127 mm) with fittings.

•• •

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 the machine manufacturer.
✔ Read and follow all installation instructions.

L150

EL150K1

**Products covered by this literature comply with EMC Council directive 89/336/EEC regarding

electromagnetic compatibility except as noted.

**

CAUTION:

Certain danger to human and to equipment
such as applied in a mobile or marine application may occur
if some equipment is stopped without pre-warning. It is
therefore, recommended that monitored functions be limited

to alarm only or to alarm before shutdown in such applications.

WARNING

L-7758N page 2 of 4

4-13/16 in.

(122 mm)

3-25/32 in.

(96 mm)

4-1/2 in.

(114 mm)

Mounting Holes

1/2 NPT

1/2 NPT

Back Connect

1/4 NPT

2-3/4 in.
(70 mm)

9/32 in. (7 mm)
diameter holes

2 places

Mounting

Ears (2)

Test
Knob

5-9/16 in.
(141 mm)

4-11/16 in.

(119 mm)

5-1/2 in.

(140 mm)

Mounting Holes

1/2 NPT

1/2 NPT

Back Connect

6 in.

(152 mm)

1/2 NPT

Connection

1/2 NPT

3-3/8 in.
(86 mm)

5/16 in. (8 mm)
diameter holes

2 places

DIMENSIONS

PS FITTINGS INSTALLATION

LEVEL SWICHGAGE

®

INSTALLATION

WARNING:

Perform all installations with the power source “OFF”. Be sure engine and radiator have

cooled and coolant pressure has been relieved. SEVERE BURNS can result. Never remove radiator cap on a hot

A Murphy PS fitting is used when there is no threaded fitting in the top
tank of the radiator to attach tubing for the L150/EL150 series level
SWICHGAGE

®

.

• P/N 15-00-0107 (PS) Accepts 1/4 in. (6 mm) O.D. copper tubing.

• P/N 15-01-0167 (PS Barbed) Barbed fitting accepts 1/4 in.

(6 mm) I.D. flexible tubing and hose clamp.

• P/N 15-01-0202 (PS-D) Accepts 1/2 in. (13 mm) I.D. hose;

1/4 in. (6 mm) copper tube.

1. Determine the entry point into the radiator top tank. See Level
SWICHGAGE

®

Installation for proper location. Drill 5/8 in. (16 mm)

diameter hole in top tank of radiator. Be sure chips do not fall inside
the tank. Remove any burrs on the hole wall.

2. Insert the rubber grommet of the PS Blind Hole Fitting. Tighten the
jam nut while holding the fitting from turning in the hole. The jam
nut will pull the tapered grommet into the hole from the inside of the
top tank causing the grommet to expand and seal the hole.

3. Attach the appropriate tubing or hose for the PS Fitting.

EL150EX

15-00-0107

15-01-0167

15-01-0202

L150

EL150K1

IMPORTANT:

Operation of the L150/EL150K1 is different for a
pressurized cooling system than for an atmospheric (non-pressurized)
system. Installation of the L150/EL150K1 is only slightly different for each
system. Connection of the top tube connection is the major difference.
Differences will be noted in the installation instructions.

Installation Notes

1. All top radiator connections must be away from the return hose

turbulence.

2. All bottom radiator connections must be away from the suction hose.

3. The L150/EL150K1 must be attached to a mounting plate on the radiator

or other framework.

CAUTION:

If the L150/EL150K1 is NOT attached to the radiator, use
high temperature quality flexible hose for the top and bottom connections
to maintain the shock mounting protection for the radiator.

Pressurized and Atmospheric Systems

1. Drain the cooling system.

2. For a PRESSURIZED COOLING
SYSTEM (Figure 1) the shutdown

point is determined by the entry point
A of the tube connection into the top
tank. The engine will shutdown when
coolant level drops below this
connection (see step 4).

If the radiator has a SHALLOW
UPPER TANK, you can make entry

from the top as illustrated in Figure 2.
Insert the copper tube until it is slightly
above the core. Secure the fitting.

4-13/16 in.

(122 mm)

4-15/16 in.

(125 mm)

4-1/2 in.

(114 mm)

Mounting Holes

1/2 NPT

1/2 NPT

Back Connect

1/4 NPT

2-3/4 in.
(70 mm)

9/32 in. (7 mm)
diameter holes

2 places

11/16 in.
(17 mm)

Test

Knob

A

Figure 1: Pressurized System

L-7758N page 3 of 4

LEVEL SWICHGAGE

®

INSTALLATION (continued)

For a PRESSURIZED system the tip of the copper tube will be the
shutdown level.

3. For ATMOSPHERIC
(non-pressurized) and
PRESSURIZED CROSS FLOW
COOLING SYSTEMS the

shutdown point is determined by
the mounting position of the
L150/EL150K1 relative to the top
tank of the radiator (see step 5).

4. For a PRESSURIZED SYSTEM,
determine the point of entry (tube
connection) in the radiator top
tank (away from the top hose
connection). Many radiators have
a pipe nipple provided. If a
connection is not provided, you must either weld or solder a fitting or
use one of the Murphy PS fittings (see PS Fittings Installation page

2). This connection should be as close to the radiator core as possible.

For MARINE AND MOBILE EQUIPMENT installations, the top
tank connection should be near the vertical centerline of the radiator.
This will compensate for changing level due to roll and pitch of the
machine during operation.

5. For an ATMOSPHERIC SYSTEM a tube connection in the top tank
may not be required. Determine the lowest desired level of coolant in
the top tank. Mount the L150/EL150K1 so that the mounting ears are
approximately 1/4 in. (6 mm) above that level (Figure 3).
A back mounting option is available for the L150 and EL150K1 for
radiators with fabricated steel top tank and/or for use with some
condensor cooling systems.

For an ATMOSPHERIC system install a 1/4 in. (6 mm) diameter
tube in the top fitting of the L150/EL150K1. This tube MUST
EXTEND ABOVE the top tank. Form the tube into a cane so that the
open end of the tube points down but still extends ABOVE the
HIGHEST coolant level. The tube can be connected to the top tank if
desired. Follow instructions for a PRESSURIZED SYSTEM.

6. For most applications, the bottom tube connection is made at the drain
cock. Remove the drain cock and install a brass tee. Reinstall the
drain cock into the tee. Attach a copper or other suitable tube to the
remaining opening of the tee and to the bottom connection of the
L150/EL150K1.

If a drain cock is not provided, you must attach a fitting or use a
Murphy PS fitting the same as for the top tank instructions.

7. Wire according to appropriate alarm or shutdown circuits (see

Standard Electrical Diagrams on page 4).

8. Refill the cooling system according to manufacturer’s instructions.

9. Start the engine and allow it to run until the thermostat opens.

Increase engine speed to the FULL operating speed and observe that
the indicating pointer remains at or near the full position. If the
pointer drops to the LOW position shutdown or alarm will occur due
to coolant flow through the L150/EL150K1. If alarm or shutdown
occurs, drain the coolant - or clamp off the upper and lower hoses.

CAUTION:

BE SURE SYSTEM PRESSURE IS RELIEVED

AND HOT COOLANT CANNOT ESCAPE. Remove the four (4)

mounting screws holding the cover assembly. Invert the float chamber
so that the 1/2 NPT connection is on top and the 1/4 NPT connection is
on bottom. Reinstall the float and cover assembly in the upright
position. Install larger I.D. tubing from the top of the float chamber
(1/2 NPT) to the radiator top tank. The smaller 1/4 NPT connection on
the bottom will restrict coolant outflow from the L150/EL150K1.
Check for unrestricted float movement by rotating the switch test knob.

Refill the cooling system and repeat step 9.

10. Place a catch basin under the drain cock. Open the drain cock and

observe that coolant is leaving the radiator.
For a PRESSURIZED cooling system, shutdown will occur when
coolant drops below the entry point of the top tank tube connection.
For an ATMOSPHERIC OR CROSS FLOW PRESSURIZED
COOLING SYSTEM, shutdown will occur when coolant drops
approximately 1/4 in. (6 mm) below the level of the case mounting ears.
If shutdown does not occur, adjust the L150/EL150K1 mounting as
described above.

CAUTION:

DO NOT ALLOW ENGINE TO RUN WHEN
COOLANT DRAINS BELOW THE UPPER TANK. ENGINE
DAMAGE CAN OCCUR.

11. Periodically test switch operation by rotating the test knob on the face of

the L150/EL150K1. Rotating the knob forces the pointer mechanism
against the contact screw (L150) or the snap switch actuator (EL150K1).

Condensor/Radiator System

1. Mount the L150/EL150K1 so that the horizontal center line of the

L150/EL150K1 is approximately 1/4 in. (6 mm) above the minimum
coolant level in the engine head.

NOTE: On some engines it is possible to use

the back connection option and attach the
L150/EL150K1 directly to the engine
cylinder. Kits are also available for some
engines.

2. Attach a copper tube from the top

connection of the
L150/EL150K1
to the radiator top tank.

3. Wire and test the

system according to above
instructions for Pressurized
and Atmospheric systems.

Figure 3:

Deep Upper Tank

Figure 2:

Shallow Upper Tank

Normal
Coolant
Level

Mounting

Ears

Low
Level
Shutdown
Point

Low
Level
Shut­down
Point

Figure 4: Atmospheric System

Figure 5:

Condensor/Radiator System

Low Level
Shutdown

Point

L-7758N page 4 of 4

REPAIR KITS

STANDARD ELECTRICAL DIAGRAMS

Repair kits are available for the L150, EL150K1 and EL150EX models.
When ordering a repair kit specify model repair kit number from chart below:

Model Components Repair Kit No.

L150 All parts except case/body 15-00-0138

Case/body assembly 15-00-0101

EL150K1 All parts except case/body 15-00-0139

Lens and switch assembly 15-00-0100
Case/body assembly 15-00-0101

EL150EX Cover and float assembly 15-00-0110

Lid assembly 15-00-0108

Switch/Terminal assembly 15-00-0109

Replacing the Float and Cover
Assembly for the L150 and EL150K1

1. As applicable, shut off liquid to the SWICHGAGE®or drain the

system level below the SWICHGAGE

®

.

2. Disconnect electrical lead(s), one at a time and tag for reinstallation.

3. Disconnect conduit on EL150K1.

4. Remove the four screws that secure the float and glass assembly

to the case.

5. Remove and discard the old float and cover assembly.

6. Remove and discard the old gasket.

7. Install the new gasket.

8. Install the new float and cover assembly and secure it with

four screws.

9. Re-connect the conduit on EL150K1.

10. Re-connect the electrical lead(s).

11. As applicable, open valves to the SWICHGAGE

®

or refill the system

to proper level.

12. Check the SWICHGAGE

®

for proper operation at the full indicating

position. (Alarm not operated/engine continues to operate.)

13. Check the SWICHGAGE®, alarm/shutdown circuit, by rotating the test

knob toward the low level point of the dial: alarm is operated/engine
shuts down.

14. Check for unrestricted float movement by rotating the switch test knob.

15. Replacement of the float and cover assembly is complete.

WARNING:

Perform the following operation with
the power source “OFF”. Be sure engine and radiator
have cooled and coolant pressure has been relieved.

SEVERE BURNS can result. Never remove radiator cap on a hot

WARNING:

PERFORM THE WIRING OPERATION WITH THE POWER SOURCE “OFF”.

CAUTION:

On some high voltage CD ignition
systems, it may be necessary to coat the L150 contact
screw head with RTV to prevent “tracking” and false

contact operation during wet or high humidity conditions. Use
of the EL150K1 is recommended in these cases.

L150 EL150K1 EL150EX

NOTE: All models shown with pointer in full position.

CONTROL SYSTEMS & SERVICES DIVISION

P.O. Box 1819; Rosenberg, Texas 77471; USA
[phone] fax [phone]

e-mail [e-mail]

MURPHY DE MEXICO, S.A. DE C.V.

Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje
San Luis Potosí, S.L.P.; México 78384
[phone] fax [phone]
Villahermosa Office [phone]
e-mail [e-mail]
www.murphymex.com.mx

FRANK W. MURPHY, LTD.

Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.
[phone] fax [phone]
e-mail [e-mail]
www.fwmurphy.co.uk

MURPHY SWITCH OF CALIFORNIA

41343 12th Street West
Palmdale, California 93551-1442; USA
[phone] fax [phone]
e-mail [e-mail]
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
[phone] fax [phone]

e-mail [e-mail]

FW Murphy

P.O. Box 470248
Tulsa, Oklahoma 74147 USA
[phone]

fax [phone]
e-mail [e-mail]

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. 096699N

Warranty

A limited warranty on materials and workmanship is given with this FW Murphy product.

A copy of the warranty may be viewed or printed by going to www.fwmurphy.com/support/warranty.htm

Full

NC-Red

NO-Black

Common-

Low

White

Low

Full

NC

Full

NO

C

Low