Low Airflow/High Pressure Due to Clogged Recoup Coil

Make:  All

Model or Series:  All

Type:  Add-On Heat Pump & 90% Gas Furnace

Problem Description:  Heat pump kicking-out on high pressure in heating mode.

Observed Symptoms:  

• Suction pressures a little low, head pressure normal in cooling
• Head pressure climbs above 500 in heating
• Liquid line a little hot in heating mode
• Gas furnace kicks-off on limit
• Moderate to low airflow from registers
• Filters clean
• Indoor coil clean
• Fan speed on High
• Static pressures low

Solution:  Dirty recoup coil

Additional Information:  

• The evaporator coil had been brushed & chemically-cleaned previously.
  • A dirty evaporator coil with a 90% gas furnace should always alert to a dirty recoup coil. 
  • Airflow must go through the recoup coil before getting to the evaporator.