Troubleshooting
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Heat Pump Controller
8733819577 (2019/02)
Heat Pump Controller
Subject to change without prior notice
Table 8 Troubleshooting HTG-CLG
POWER STATUS
LED OFF
X
X
Main power problems (line
voltage)
Check line voltage circuit breaker and
disconnect.
Check for line voltage between L1 and L2
on the contactor.
Check for 24 VAC between (R) and (C) on
HPC P1.
Check for continuity across fuse F4.
Check primary/secondary voltage on
transformer.
HPS STATUS RED
LED FAULT CODE 1
HIGH PRESSURE
X
Reduced or no water flow
Check pump operation or valve
operation/setting.
Check water flow, adjust to proper flow
rate.
Verify water flow condition with the
Bosch EasyStart app.
Water temperature out of
range
Verify temperature value with Bosch
EasyStart app.
Bring water temp within design
parameters.
X
Reduced air flow
Check for dirty air filter and either clean
or replace.
Check fan motor operation and airflow
restrictions.
Review airflow setting with Bosch
EasyStart app.
Dirty Air Coil, construction dust, etc.
X
Air temperature out of
range in heating
Bring return air temperature within
design parameters.
X
X
Overcharged with
refrigerant
Check and service system refrigerant.
Bad High Pressure Switch
Verify continuity/replace switch.
LPS STATUS LED
FAULT CODE 2
LOW PRESSURE
LOSS OF CHARGE
X
X
Insufficient charge
Check for refrigerant leaks.
X
X
Compressor pump down at
start-up
Check charge and start-up water flow.
Use the Bosch EasyStart app to verify
that there are no water flow warnings.
Troubleshooting Heating/Cooling
Indicator
HTG CLG
Behavior
Solution/Action
