Evaporator coil - inspection procedures

Air Conditioning and Heat Pumps · Condensate System · printed page 219 (PDF page 220)

Book index entries

Inspection Procedure Evaporator Coil – for Air Conditioning – Inspection Procedure Evaporator Coil Evaporator Coil – for Air Conditioning

Text in the illustration

warm refrigerant gas cold liquid refrigerant more refrigerant may be required or the the unit is low on refrigerant
evaporator coil
warm air from inside house 75°F
warmer
flow direction
warm refrigerant gas (typically 50°F)
cooler air can now be sent back into the house through the ductwork 55°F
cold liquid refrigerant (typically 20°F)
check the temperature above and below the coil - a 15°F to 20°F temperature drop is desirable (beyond the Standards)
If the coil is visible, look for bent fins, dirt buildup or a dirty air filter that could reduce airflow - expect an increased temperature drop in this case
if the temperature drop is less than 15° or 20°, more refrigerant may be required or the compressor may not be working at peak efficiency
the coil should be uniformly wet with condensation (dryness at the top may mean the unit is low on refrigerant)
there should be no ice buildup on the coils - if present, this may indicate low airflow

Generated explanation

The illustration shows a finned evaporator coil with warm indoor air entering at 75°F and cooled air leaving at 55°F for return to the house through ductwork. Blue and red refrigerant lines indicate cold liquid refrigerant entering the bottom of the coil and warmer refrigerant gas leaving the top, with arrows identifying flow direction. Inspection notes recommend checking the air temperature drop across the coil and looking for bent fins, dirt buildup, or a dirty air filter that could restrict airflow. Additional notes discuss inadequate cooling, nonuniform condensation, and ice buildup as possible indicators of refrigerant, compressor, or airflow problems. These conditions are described as inspection checks rather than visibly illustrated damage.

Components

evaporator coil coil fins liquid refrigerant line refrigerant gas line

Defects shown

Bent coil fins (noted)Dirt buildup on coil (noted)Dirty air filter restricting airflow (noted)Insufficient temperature drop across coil (noted)Low refrigerant charge (noted)Reduced compressor efficiency (noted)Dryness at top of coil (noted)Ice buildup on coil (noted)Low airflow across coil (noted)