Troubleshooting - Trane UH1B040A9241C Series Service Facts

TROUBLESHOOTING

Is line voltage measured between
motor common and applied speed
UH1-DH1-SF-1L
Turn the FAN switch to
"ON" at the thermostat
Is there any air
flow?
NO
Check for dirty air filter,
duct work damage or
Is the fan wheel
YES restrictions around the
running?
furnace coil and
repair as needed
NO
Is the high voltage
power supplied to NO voltage connection
the unit?
YES
Is 24 VAC measured
between "R" (transformer
hot) and "B/C" (transformer
NO
common) at the low voltage
field connections?
YES
Is 24 VAC measured
between "G" and "B/
C" at the low voltage
connections?
YES
NO
tap at IFC?
CIR-N and HEAT-H
YES
NO
Is microfarad reading of fan
motor run capacitor within
10% of rated value?
YES
Furnace PSC fan motor - No Air Flow
Repair high
to unit.
Is the proper line
voltage present at
YES Is fuse blown?
the transformer?
NO
Repair wiring
between incoming
power supply and
transformer.
Check thermostat
NO and wiring to
thermostat.
Replace the IFC
Replace run
capacitor.
Replace fan motor
and run capacitor.
Service Facts
YES Replace fuse.
Replace
NO
transformer.
27