measure 1.164 inches free length and have a 0.750-
inch working length with a load of 1 pound, plus or
minus 0. 1 pound, applied. If spring fails to meet
these requirements, replace spring.
b. Fuel Regulator Valve. Remove cover plate and
disconnect fuel tube assembly at orifice assembly.
a. Regulator Valve. Connect a fuel supply (3 to
15 psi) and 24 Vdc to regulator. Regulator valve
should operate and produce a steady stream of 21 to 23
cubic centimeters of fuel per minute (at 70° F). If
fuel rate is not within these tolerances, adjust regula-
tor valve by turning the adjusting screw clockwise to
increase flow rate or counterclockwise to decrease
flow rate. This test can be made using a graduated
container and stop watch.
b. Igniter. With igniter removed from heater,
ground igniter and supply 24 Vdc power to igniter term-
inal. Igniter should draw approximately 10.5 amperes
and heat to a bright red color in a few seconds.
c. Flame Switch.
(1) Test flame switch using an ohmmeter to check
continuity of microswitch.
Depress microswitch button.
This will be the ignition or start position of switch.
(2) Continuity should be made between two NO
(normally open) terminals and also between each of
NO terminals and common terminals. There should
e an open circuit between two NC (normally closed)
erminals and also between common terminals and two
(3) Release microswitch button. This will be
run position of microswitch. Continuity should be made
between two NC terminals and common terminals. There
should be no continuity made between the NO ignition or
start terminals, or NO terminals and common termin-
als. Replace microswitch if it does not check out cor-
The common terminal is connected to
blower motor which operates at all
times when heater is in operation.
d. Coolant Pump and Motor Assembly.
(1) After coolant pump has been overhauled, it
must be tested before being reinstalled on heater.
(2) Mount motor and pump assembly on a test
stand and install proper fittings in inlet and outlet ports.
Attach hose line from supply tank to port marked IN.
(3) Attach discharge line with pressure gauge and
needle valve to port marked OUT and return ,0 supply
(4) Attach electrical plug to motor receptacle and
plug in to dc power supply.
(5) Turn power switch on and run unit for ap-
proximately 15 minutes on 24 Vdc.
(6) Close valve in outlet line. (make sure dis-
charge pressure does not exceed a maximum of 30 to
50 psi when closing this valve). Open and close valve
a few times to check consistency of valve performance.
(7) To check pump for rated flow and pressure,
adjust valve in discharge line until a reading of 2 psi
is obtained on pressure gauge. Using a suitable timer,
check for rated coolant flow of 80 gph (gallons per hour)
minimum at 2 psi discharge pressure (at 70° F.) Am-
perage draw must not exceed 6 amperes during this
test. Observe smoothness of operation of both pump
and motor. Seal leakage of 1 cc per hour is maximum
when pump is operating at 2 psi discharge.
(8) Turn power supply off, then remove discharge
line and fitting from OUT port. Plug this port and ap-
ply 40 psi hydrostatic pressure for 20 minutes to inlet
port. No leakage shall be evident during this test.
(1) The blower motor, (without coolant pump at-
tached) can be tested when installed in heater.
(2) Check end play on motor shaft, grasp short
end and rotate in either direction at the same time
moving in and out.
The end play should not exceed
0.010 to 0.025 inch, and fan should rotate freely.
(3) Use a strobe light to check motor rpms
(blower installed on heater). The fan speed should be
approximately 8500 rpm when 24 Vdc is applied.
(4) The blower motor should not draw more than
6 amperes (at 70° F).
Higher amperage will indicate
a defective motor. Replace defective motor.
Refer to Operator and Organizational Maintenance
Manual and install fuel-burning heater kit.
Section IL ELECTRIC WINTERIZATION KIT
The electric winterization kit is available as an aid
in starting the generator set in temperatures from
25° F to -65° F. The electrical winterization kit
consists of a heat exchanger, control box, coolant
pump, thermostat and accessories. The primary
purpose of the kit is to maintain the set in a heated
condition, at any ambient temperature from 1250 F
to -65° F to enable it to accept 75% of rated load in
one step within 20 seconds after starting action is
The coolant temperature is thermostat-
tally controlled at 130° F to 150° F.
Change 1 17-7