In a comfort cooling system the evaporator coil runs with a saturation temperature around 40 degrees F, cold enough to remove moisture but above freezing. Air passing over it drops in temperature and gives up water, which drains from the pan. By the outlet the refrigerant should be all vapor and a few degrees superheated. Low airflow, a dirty coil or low charge drag evaporator temperature down until the coil ices.
Evaporator's iced solid halfway up, check the filter and the blower before you even put gauges on it.
Check airflow before charge on every cooling call; most iced or underperforming evaporators are an airflow problem.
Also heard as
- evap
- evaporator coil
- evap coil
- DX coil
- indoor coil
Related terms
Superheat
How many degrees refrigerant vapor is above its boiling point at the pressure it is at.
Iced up
Describes an evaporator coil or suction line coated in ice because it is running below freezing.
Metering device
The restriction that drops refrigerant from high side to low side pressure and controls how much enters the evaporator.
Drain pan
The pan under a cooling coil that catches condensate and routes it to a drain line.