Bosch GreenSource SM024 - BROWNOUT FAULT; NOT COOLING FAULT

Greensource CDi Series SM
Greensource CDi Series SM Model8733819578 (2019/02)
50 | Unit Troubleshooting
Subject to change without prior notice
BROWNOUT FAULT
Compressor,
Loop Pump,
Blower, Auxiliary
Heat
Nominal voltage below
recommended value
Check power supply and 24 VAC
voltage before and during operation.
Check power supply wire size are in
accordance with local codes. Check
compressor starting load. Check 24
VAC and unit transformer tap for
correct power supply voltage. Service/
replace.
Nominal voltage above
recommended value
Check power supply and 24 VAC
voltage before and during operation.
Check 24 VAC and unit transformer
tap for correct power supply voltage.
Service/replace.
FREEZE
EVAPORATOR
FAULT
Compressor,
Loop Pump
Reduced airflow
Check for dirty air filter or coil. Check
fan motor operation and airflow
restrictions.
Undercharged with
refrigerant
Check and service system refrigerant.
RAT outside of nominal
range
Bring air temperature within range.
Bad thermistor
Check temperature and impedance
correlation. Service/replace.
HIGH-VOLTAGE
WARNING
Appliance
Controller sensed power
increase of 25% above
recommended operation
range
Shut down the appliance and check
the loop and HRP fuse continuity.
Service/replace.
NOT COOLING
FAULT
Appliance
Discharge temperature
greater than return air
temperature
Verifying reversing valve operation.
Service/replace.
HEATING ON COOL
DEMAND
Appliance RAT-DAT <-10ºF
Verifying reversing valve operation.
Service/replace.
NOT HEATING
FAULT
Appliance
Discharge temperature less
than return air temperature
Loop has reached a temperature
outside the unit operating range.
Verify reversing valve operation.
Service/replace.
COOLING ON
HEATING DEMAND
Appliance RAT-DAT >10ºF
Loop has reached a temperature
outside the unit operating range.
Verify reversing valve operation.
Service/replace.
LWT HIGH-LIMIT
TRIP
Warning
High loop temperature
detected. LWT above 120ºF
Verify loop pump and appropriate
water flow. Service/replace.
EWT HIGH-LIMIT
TRIP
Warning
High loop temperature
detected. EWT above
110.5ºF.
Verify loop pump and appropriate
water flow. Service/replace.
Unit Troubleshooting
Problem Check Possible Cause Action