Other Phenomena-Abnormal - A.O. Smith CAHP-MC-38 Installation, Operation And Maintenance Instructions

Heat pump units does not
start as soon as the system is
switched on.
The heat pump fan stops
under high ambient
temperature.

12.3. Other Phenomena-Abnormal

Phenomena
The central controller
displays "N/A" for some
paramters.
Heat pump units does not
start after the system is
switched on for a long time.
The circulation pump is
operating but with abnormal
noise.
Lower heating capacity and
the heat pump units are
always operating without
stop
Compressor does not start
remove the frost from the
evaporator to ensure efficient
system operation after a certain
time operation.
This is normal phenomeno. To
protect the compressor from
frequent cycle, the heat pump
unit will not start within 3
minutes from last stop.
This is normal phenomeno. The
fan will possibly stop to reduce
the evaporative pressur for
compressor protection under
high ambient temperature
operation.
Possible Reason
Communication is not
established successfully.
1. Power supply error.
2. Loose wiring.
3. Bad fuse.
4. Operation timer expired.
1. No water in piping
system.
2. Air in pipin system.
3. The valves are not fully
open.
4. Blocked water filter.
1. Bad insulation on water
side and high standby
loss.
2. Bad performance of
ambient coil.
3. Insufficient water.
4. Small tank and the hot
water system is
undersized.
1. Bad compressor
contactor.
2. Loose wiring.
3. Compressor overload
protection.
Solutions
Please check the communication
cables between the central
controller controller and display,
among the heat pump units.
1. Inspect the power supply.
2. Inspect the wiring and fix.
3. Replace the fuse.
4. Check on the timer setting.
1. Inspect the water piping
system.
2. Exhaust the air from the
piping system.
3. Open all the valves fully.
4. Clean the water filter.
1. Improve the water system
insulation.
2. Inspect the air circulation
around the unit.
3. Clean the water filter or
exhaust the gas in the system.
4. Improve the system design by
inquiring
manufacturer.
1. Replace the contactor.
2. Inspect the wiring and fix.
3. Check the UIM for error code.
4. Reset the tank temperature.
5. Clean the water filter or
system