Refrigeration 101

[Gary]

Hey Gary,

What are the effects of excessive superheat/subcooling and lack of superheat/subcooling.

Perhaps we can run a few example system diagnoses here.

Example:

Time of Day: Noon
Type of System: Rooftop Packaged
Outside Air Temp: 103F
Indoor Air Temp @ Return:86F
Indoor Air Temp @ Supply:83F
You inspect each section of the system visually.

Indoor Coil is clean and clear of obstruction and the air filter is new and clean.

The Outdoor coil is slightly soiled, but nothing to be seriously concerned about.

Outdoor Fan: Operating
Indoor Fan: Operating
Compressor: Operating


Complaint: The unit is blowing warm air.



This should be a pretty simple one... you don't need superheat or subcooling to figure it out.

Yes... you do.

Could be undercharge, could be restriction, could be blown valves in the compressor.

You might think you know what the most likely problem is, but you don't really know what the problem is until you check the subcooling and the superheat.

While you're at it, check to see what type of metering device you have.