Carrier 50YFV Installation, Operation And Maintenance Instructions page 57

R e s i d e n t i a l D i g i t a l P a c k a g e d U n i t s G T- P B S e r i e s - 6 0 H z P u r o n
Symptom
Low Dischage Air
Temperature in Heating
High Humidity
Only Compressor Runs
Unit Doesn't Operate in
Cooling
Modulating Valve
Troubleshooting
Htg Clg Possible Cause
X Too high of air flow
X Poor performance
X Too high of air flow
X Unit oversized
X X Thermostat wiring
X X Fan motor relay
X X Fan motor
X X Thermostat wiring
X Reversing Valve
X Thermostat setup
X Thermostat wiring
Improper output setting
No valve output signal
X X
No valve operation
Performance Troubleshooting (cont.)
Solution
Check fan motor speed selection and airflow chart
See "Insufficient Capacity"
Check fan motor speed selection and airflow chart
Recheck loads and sizing check sensible clg load and
heat pump capacity
Check G wiring at heat pump. Jumper G and R for fan
operation.
Jumper G and R for fan operation. Check for Line voltage
across blower relay contacts.
Check fan power enable relay operation (if present)
Check for line voltage at motor. Check capacitor
Check thermostat wiring at or DXM2. Put in Test Mode
and then jumper Y1 and W1 to R to give call for fan,
compressor and electric heat.
Set for cooling demand and check 24VAC on RV coil.
If RV is stuck, run high pressure up by reducing water flow
and while operating engage and disengage RV coil voltage
to push valve.
For DXM2 check for "O" RV setup not "B".
Check O wiring at heat pump. DXM2 requires call for
compressor to get RV coil "Click."
Verify the AO-2 jumper is in the 0-10V position
Check DC voltage between AO2 and GND. Should be O
when valve is off and between 3.3v and 10v when valve
is on.
Check voltage to the valve
Replace valve if voltage and control signals are present at
the valve and it does not operate
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