Performance Troubleshooting
Performance Troubleshooting Htg Clg Possible Cause Solution
Insufficient capacity X X Dirty Filter Replace or clean
Not cooling or heating properly X   Reduced or no Air flow in heating Check for dirty air filter and clean or replace Check fan motor operation and airflow restrictions Too high of external static. Check static vs blower table
    X Reduced or no Air flow in cooling Check for dirty air filter and clean or replace Check fan motor operation and airflow 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 significantly different, duct leaks are present
Unit Doesn't Operate in Cooling 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 Cold Check load, loop sizing, loop backfill, ground moisture.
High Head Pressure X   Reduced or no Air flow in heating Check for dirty air filter and clean or replace Check fan motor operation and airflow restrictions Too high of external static. Check static vs blower table
    X Reduced or no water flow in cooling Check pump operation or valve operation/setting Check water flow adjust to proper flow rate
    X Inlet Water too Hot Check load, loop sizing, loop backfill, ground moisture.
  X   Air Temperature out of range in heating Bring return air temp within design parameters
    X Scaling in water heat exchanger Perform Scaling check and clean if necessary
  X X Unit Overcharged Check superheat and subcooling. Reweigh in charge
  X X Non-condensables in system Vacuum system Reweigh in charge
  X X Restricted metering device Low Suction Pressure Check superheat and subcooling per chart. Replace.
Low suction pressure X   Reduced water flow in heating Check pump operation or water valve operation/setting Plugged strainer or filter. Clean or replace. Check water flow adjust to proper flow rate
  X   Water Temperature out of range Bring water temp within design parameters
    X Reduced Air flow in cooling Check for dirty air filter and clean or replace Check fan motor operation and airflow 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 temp within design parameters
  X X Insufficient charge Check for refrigerant leaks
Low discharge air
temperature in heating		 X   Too high of air flow Check fan motor speed selection and airflow chart
  X   Poor Performance See 'Insufficient Capacity'
High humidity   X Too high of air flow Check fan motor speed selection and airflow chart
    X Unit oversized Recheck loads & sizing
check sensible clg load and heat pump capacity