Bosch CE025 Installation And Maintenance Manual page 29

Troubleshooting
Insufficient
Unit undersized
cooling or
heating Loss of conditioned
air by leakage
Airflow
Refrigerant charge
Compressor
Reversing Valve
Operating
pressures
TXV
Moisture,
noncondensables
UPM board
Compressor will
not run, no fault
trouble
blink code
shooting
Revised 05-12
Recalculate heating and or cooling loads. If excessive, possibly adding
insulation and shading will rectify the problem
Check for leaks in duct work or introduction of ambient air through
doors or windows
Lack of adequate air flow or improper distribution of air. Replace dirty
filter
Low on refrigerant charge causing inefficient operation
Check for defective compressor. If discharge is too low and suction
pressure is too high, compressor is not pumping properly. Replace
compressor.
Defective reversing valve creating bypass of refrigerant from discharge
of suction side of compressor. Replace reversing valve
Compare unit operation pressures to the pressure/temperature chart
for the unit.
Check TXV for possible restriction or defect. Replace if necessary.
The refrigerant system may be contaminated with moisture or
noncondensables. Reclaim refrigerant, replace filter dryer, evacuate the
refrigerant system, and recharge with factory recommended charge.
Note: a liquid line dryer may be required.
Is Green
Power LED
light on and
no Red
Blink Code?
Subject to change without prior notice
Yes
Is there
power to
Yes
the "Y" Call
(C-Y)?
No
- Check all
No
power supplies
- Check all
safety switches
CE Series
UPM Board
Yes
is Good
Is there 24 V
power from
C to CC?
Check for Red
No
Blink Code.
If Red Blink
Code is not
Check
present, replace
thermostat
UPM Board
settings and
configurations
for heat
pumps, and
wiring
6 720 220 048
29