Bosch BP070 - Page 27

6 720 220 045
Revised 01-11 Subject to change without prior notice
Troubleshooting CP/BP Series 27
Insufcient
cooling or
heating
Unit undersized
Recalculate heating and or cooling loads. If excessive, possibly
adding insulation and shading will rectify the problem
Loss of conditioned
air by leakage
Check for leaks in duct work or introduction of ambient air
through doors or windows
Airow
Lack of adequate air ow or improper distribution of air.
Replace dirty lter
Refrigerant charge
Low on refrigerant charge causing inefcient operation
Compressor
Check for defective compressor. If discharge is too low and
suction pressure is too high, compressor is not pumping
properly. Replace compressor.
Reversing Valve
Defective reversing valve creating bypass of refrigerant from
discharge of suction side of compressor. Replace reversing
valve
Operating
pressures
Compare unit operation pressures to the pressure/temperature
chart for the unit.
TXV
Check TXV for possible restriction or defect. Replace if
necessary.
Moisture,
noncondensables
The refrigerant system may be contaminated with moisture
or noncondensables. Reclaim refrigerant, replace lter dryer,
evacuate the refrigerant system, and recharge with factory
recommended charge.
UPM board
trouble
shooting
Compressor will
not run, no fault
blink code
Is Green
Power LED
light on and
no Red
Blink Code?
Yes
No
Is there
power to
the “Y” Call
(C-Y)?
No
Yes
Check
thermostat
settings and
configurations
for heat
pumps, and
wiring
Is there 24 V
power from
C to CC?
No
Yes
UPM Board
is Good
Check for Red
Blink Code.
If Red Blink
Code is not
present, replace
UPM Board
- Check all
power supplies
- Check all
safety switches