Comfort-Aire HTH Series - Manual (Page 46)

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Installation, Operation & Maintenance HTV/HTD/HTH SERIES Heat Controller, Inc.
Performance Troubleshooting
Performance Troubleshooting Htg Clg Possible Cause Solution
Insuffi cient capacity/ Not
cooling or heating
X X Dirty 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.
X X Leaky duct work
Check supply and return air temperatures at the unit and at distant duct registers
if signifi cantly different, duct leaks are present.
X X Low refrigerant charge Check superheat and subcooling per chart.
X X Restricted metering device Check superheat and subcooling per chart. Replace.
X Defective reversing valve Perform RV touch test.
X X Thermostat improperly located Check location and for air drafts behind stat.
X X Unit undersized Recheck loads & sizing. Check sensible clg. load and heat pump capacity.
X X Scaling in water heat exchanger Perform scaling check and clean if necessary.
X X Inlet 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.
X X Unit overcharged Check superheat and subcooling. Re-weigh in charge.
X X Non-condensables in system Vacuum system and re-weigh in charge.
X X Restricted 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.
X X Insuffi 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.