TP-6200 10/12 145Section 3 Scheduled Maintenance
Emissions certified models use a single electronic-
controlledpressure regulator (EPR) for both fuels. A tee
fittingconnects both fuels together upstream of the EPR.
During operation when using the secondary fuel, it is
normal for a small amount of secondary fuel to seep
backthrough the primary fuel solenoid valve. Tocounter
this situation, one of two methods is used depending
upon the generator set model: (1) a second solenoid
valve (identical to the primary fuel solenoid valve) is
installed in a reverse configuration on the primary fuel
side or (2) a small vent line is installed between the
primary fuel inlet and the air intake through a fuel
solenoid valve.

3.6.5 Crankcase Ventilation (CCV)

Heater Kit GM78171-KP1

(125/150REZG models)

The crankcase ventilation (CCV) heater kit provides a
controlled heating source to the crankcase ventilation
system preventing freezing water buildup during cold
weather. The thermostat turns on at 4_C(40_F)and
turns off at 16_C(60_F) reducing energy consumption.
See Figure 3-11.
1. Heater element
2. Inline connector
3. Thermostat
4. AC power cord
TT-1560
1 2
3
4
Figure 3-11 Crankcase Ventilation Heater Kit
3.7 Cooling System
The cooling system maintenance information applies to
radiator-cooled models and city-water-cooled (heat
exchanger) models. The cooling systems function
similarly even though they use different components.
Radiator-cooled models have a radiator with apressure
cap and coolant recovery tank. City-water-cooled
models have a heat exchanger and an expansion/surge
tank with a pressure cap.
Note: The 20--40kW Deutz engine-powered generator
sets are oil-cooled and, therefore, do not have a
water cooling system.
Hot coolant and steam.
Can cause severe injury or death.
Before removing the pressure cap,
stop the generator set and allow it to
cool. Then loosen the pressure cap
to relieve pressure.
WARNING
Allow the engine to cool. Release pressure from the
cooling system before removing the pressure cap. To
release pressure, cover the pressure cap with a thick
cloth and then slowly turn the cap counterclockwise to
the first stop. Remove the cap after pressure has been
completely released and the engine has cooled. Check
the coolant level at the tank if the generator set has a
coolant recovery tank.
Note: Engine damage. Bleed the air from the cooling
system to prevent overheating and subsequent
engine damage.
Note: Block heater damage. The block heater will fail
ifthe energized heater element is not immersed in
coolant. Fill the cooling system before turning on
the block heater. Run the engine until it is warm,
and refill the radiator to purge the air from the
system before energizing the block heater.

3.7.1 Coolant Level Check

Check the coolant level in the coolant recovery tank.
Maintain the coolant level between the high and low
marks.
Note: Periodically check the coolant level by removing
thepressure cap. Do not rely solely on the level in
thecoolant recovery tank. Add fresh coolant until
thelevel is just below the overflow tube opening of
the filler neck.