Wet Stacking; Cold Weather Operation - Generac Power Systems MDG25IF4 Owner's Manual

Figure 3-3. Remote Start Terminal Block

Wet Stacking

The unit is powered by a diesel engine. Diesel engines
are susceptible to wet stacking if lightly loaded. Wet
stacking occurs when an engine is run at less than 30%
of its full load capacity, causing unburned fuel to
accumulate in the exhaust system. Wet stacking can be
detected by continuous black exhaust when the unit is
under a constant load. It can also cause fouling of
injectors and buildup on engine valves. Diesel engines
operate properly when applied loads are between 30%
and 100% capacity. Appropriate generator sizing is
determined by the anticipated load. If the unit is in a wet
stack condition, load the unit heavily for five hours or until
the exhaust is clear.

Cold Weather Operation

DANGER
Explosion. Do not use ether when starting an
engine equipped with glow plugs or an air intake
heater. Doing so could cause an explosion, which
will result in death or serious injury.
The engine may be equipped with optional equipment,
such as a coolant heater, oil pan heater, crankcase
ventilation heater, battery heater or fuel heater as cold
weather starting aids.
See Figure 3-4. Starting aids are required below
32°F (0°C). They will enhance starting performance
below these temperatures and may be needed to start
applications that have high parasitic loads during
cranking and start acceleration to idle. Other cold
weather starting aids are required at temperatures below
-13°F (-25°C) or at altitudes above 5000 ft (1500 m).
The use of correct grade oil (see
Types) is critical to achieving adequate cold weather
cranking speed. Synthetic oils have improved flow at low
temperatures.
The oil pan heater, battery heater and fuel filter heater (if
equipped) are activated with a thermostat and will turn on
and off as needed. The coolant heater is powered by a
Owner's Manual for MDG25IF4
A
002806
(000583)
Recommended Oil
shore power 120V electrical connection that can be
found in the convenience receptacle. The crankcase
ventilation heater is powered by the generator and will
stay on when the engine is operating in cold weather
conditions.
Figure 3-4. Cold Weather Starting Guidelines
A No Aids
B Electric Air Heat
C Block Heat
D Ether
E Electric Air Heat and Block Heat
F Ether and Block Heat
Use cold weather starting aids as needed according to
Figure 3-4. Follow supplier instructions for starting aids
provided on engine. A booster battery can be connected
if needed (see Using a Booster Battery or Charger (if
equipped)).
NOTE: Turn key to ON but do not crank engine until
Engine Preheat Indicator goes off.
NOTE: Additional information on cold weather operation
is available from your local GMP ASD.
Operation
008744
25