Carrier 50YDV - Performance Troubleshooting

Residential Packaged Units - 60Hz Puron
®
Rev.: 4 Jan., 2012
46
Functional Troubleshooting
Performance Troubleshooting Htg Clg Possible Cause Solution
Insuffi cient capacity/ Not
cooling or heating
XXDirty fi lter Replace or clean.
X Reduced or no air fl ow in heating
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.
X Reduced or no air fl ow in cooling
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.
XXLeaky duct work
Check supply and return air temperatures at the unit and at distant duct registers
if signifi cantly different, duct leaks are present.
XXLow refrigerant charge Check superheat and subcooling per chart.
XXRestricted metering device Check superheat and subcooling per chart. Replace.
X Defective reversing valve Perform RV touch test.
XXThermostat improperly located Check location and for air drafts behind stat.
XXUnit undersized Recheck loads & sizing. Check sensible clg. load and heat pump capacity.
XXScaling in water heat exchanger Perform scaling check and clean if necessary.
XXInlet water too hot or too cold Check load, loop sizing, loop backfi ll, ground moisture.
High Head Pressure
X Reduced or no air fl ow in heating
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.
X Reduced or no water fl ow in cooling
Check pump operation or valve operation/setting.
Check water fl ow. Adjust to proper fl ow rate.
X Inlet water too hot Check load, loop sizing, loop backfi ll, ground moisture.
X Air temperature out of range in heating Bring return air temperature within design parameters.
X Scaling in water heat exchanger Perform scaling check and clean if necessary.
XXUnit overcharged Check superheat and subcooling. Re-weigh in charge.
XXNon-condensables in system Vacuum system and re-weigh in charge.
XXRestricted metering device. Check superheat and subcooling per chart. Replace.
Low Suction Pressure
X Reduced water fl ow in heating.
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.
X Water temperature out of range. Bring water temperature within design parameters.
X Reduced air fl ow in cooling.
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.
X Air temperature out of range Too much cold vent air? Bring entering air temperature within design parameters.
XXInsuffi cient charge Check for refrigerant leaks.
Low Discharge Air Temperature
in Heating
X Too high of air fl ow Check fan motor speed selection and air fl ow chart.
X Poor performance See ‘Insuffi cient Capacity’
High humidity
X Too high of air fl ow Check fan motor speed selection and airfl ow chart.
X Unit oversized Recheck loads & sizing. Check sensible clg load and heat pump capacity.
Performance Troubleshooting
Only Compressor Runs
XXThermostat wiring Check G wiring at heat pump. Jumper G and R for fan operation
XX
Fan motor relay
Jumper G and R for fan operation. Check for voltage at blower relay.
XX Check fan power enable relay operation (if present).
XXFan motor Check for line voltage at motor. Check capacitor.
XXThermostat wiring
Check thermostat wiring at heat pump. Jumper Y1 and R for compressor
operation in test mode
Unit Doesn’t Operate
in Cooling
X Reversing valve
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.
X Thermostat setup Check for ‘O’ RV setup not ‘B’.
X Thermostat wiring
Check O wiring at heat pump. Jumper O and R for RV coil ‘click’ when
compressor starts.
X Thermostat wiring
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.