Carrier 50YDV Installation, Operation And Maintenance Instructions page 46

R e s i d e n t i a l P a c k a g e d U n i t s - 6 0 H z P u r o n
R e v. : 4 J a n . , 2 0 1 2
Functional Troubleshooting
Only Compressor Runs
Unit Doesn't Operate
in Cooling
Performance Troubleshooting
Performance Troubleshooting
Insuffi cient capacity/ Not
cooling or heating
High Head Pressure
Low Suction Pressure
Low Discharge Air Temperature
in Heating
High humidity
46
X X Thermostat wiring
X X
Fan motor relay
X X
X X Fan motor
X X Thermostat wiring
X Reversing valve
X Thermostat setup
X Thermostat wiring
X Thermostat wiring
Htg Clg Possible Cause
X X Dirty fi lter
X Reduced or no air fl ow in heating
X Reduced or no air fl ow in cooling
X X Leaky duct work
X X Low refrigerant charge
X X Restricted metering device
X Defective reversing valve
X X Thermostat improperly located
X X Unit undersized
X X Scaling in water heat exchanger
X X Inlet water too hot or too cold
X Reduced or no air fl ow in heating
X Reduced or no water fl ow in cooling
X Inlet water too hot
X Air temperature out of range in heating
X Scaling in water heat exchanger
X X Unit overcharged
X X Non-condensables in system
X X Restricted metering device.
X Reduced water fl ow in heating.
X Water temperature out of range.
X Reduced air fl ow in cooling.
X Air temperature out of range
X X Insuffi cient charge
X Too high of air fl ow
X Poor performance
X Too high of air fl ow
X Unit oversized
®
Check G wiring at heat pump. Jumper G and R for fan operation
Jumper G and R for fan operation. Check for voltage at blower relay.
Check fan power enable relay operation (if present).
Check for line voltage at motor. Check capacitor.
Check thermostat wiring at heat pump. Jumper Y1 and R for compressor
operation in test mode
Set for cooling demand and check 24VAC on RV coil and at DXM2 board.
If RV is stuck, run high pressure up by reducing water fl ow and while operating
engage and disengage RV coil voltage to push valve.
Check for 'O' RV setup not 'B'.
Check O wiring at heat pump. Jumper O and R for RV coil 'click' when
compressor starts.
Put thermostat in cooling mode. Check 24 VAC on O (check between C and
O); check for 24 VAC on W (check between W and C). There should be voltage
on O, but not on W. If voltage is present on W, thermostat may be bad or wired
incorrectly.
Solution
Replace or clean.
Check for dirty air fi lter and clean or replace.
Check fan motor operation and airfl ow restrictions.
Too high of external static. Check static vs. blower table.
Check for dirty air fi lter and clean or replace.
Check fan motor operation and airfl ow restrictions.
Too high of external static. Check static vs. blower table.
Check supply and return air temperatures at the unit and at distant duct registers
if signifi cantly different, duct leaks are present.
Check superheat and subcooling per chart.
Check superheat and subcooling per chart. Replace.
Perform RV touch test.
Check location and for air drafts behind stat.
Recheck loads & sizing. Check sensible clg. load and heat pump capacity.
Perform scaling check and clean if necessary.
Check load, loop sizing, loop backfi ll, ground moisture.
Check for dirty air fi lter and clean or replace.
Check fan motor operation and air fl ow restrictions.
Too high of external static. Check static vs. blower table.
Check pump operation or valve operation/setting.
Check water fl ow. Adjust to proper fl ow rate.
Check load, loop sizing, loop backfi ll, ground moisture.
Bring return air temperature within design parameters.
Perform scaling check and clean if necessary.
Check superheat and subcooling. Re-weigh in charge.
Vacuum system and re-weigh in charge.
Check superheat and subcooling per chart. Replace.
Check pump operation or water valve operation/setting.
Plugged strainer or fi lter. Clean or replace.
Check water fl ow. Adjust to proper fl ow rate.
Bring water temperature within design parameters.
Check for dirty air fi lter and clean or replace.
Check fan motor operation and air fl ow restrictions.
Too high of external static. Check static vs. blower table.
Too much cold vent air? Bring entering air temperature within design parameters.
Check for refrigerant leaks.
Check fan motor speed selection and air fl ow chart.
See 'Insuffi cient Capacity'
Check fan motor speed selection and airfl ow chart.
Recheck loads & sizing. Check sensible clg load and heat pump capacity.