Apu Control Unit - Carrier ComfortPro PC6000 Operation & Service Manual

APU
CONTROL
UNIT
STARTER
GLOW PLUGS
SOL PULL
SOL HOLD
ALT POWER
COOLANT
OIL
TEMP
ALT F/B
Figure A-4: APU Control Unit
A-6

APU CONTROL UNIT

Output Indicators
STARTER – This is the output (+) to the Starter solenoid.
GLOW PLUGS – This is the output (+) to the Glow Plugs.
SOL PULL – This is the output (+) to the Fuel Solenoid Pull windings
(Only on during cranking for the first .5 seconds).
SOL HOLD – This is the output (+) to the Fuel Solenoid Hold windings.
ALT POWER – This is the output (+) to the Alternator field windings.
Input Indicators
OIL – This is the input (-) from the Oil Pressure Switch (NC). You will see
this light illuminated when the oil pressure is below 7 psi. This will shut
the APU off when it is illuminated.
TEMP – This is the input (-) from the Overheat Switch (NO). You will see
this light illuminated when the coolant temperature is above 245°F. This
will shut the APU off when it is illuminated.
ALT F/B – This is the input (-) from the Alternator Charging light. When
the APU is not running this light will be on. When the APU is running and
the Alternator is charging this light will be out (or very dim). This will shut
the APU off when the light is illuminated.
62-11175 COMFORTPRO SERVICE MANUAL