Heat Pump Sight Glass

[rxtom1]

Will charging a heat pump with R22 and the use of a liquid line sight glass be close enough to make the system operate fairly well ?

[Brian_UK]

It all depends, what was the system originally charged with?

[texas64]

When in doubt, charge a heat pump in heat mode.

[rxtom1]

This is a factory R22 split system HP. Trying to help a friend out. My experience in the refrigeration industry has been with commercial refrigeration and not to much with AC. I know that the refrigerant charge should weighed in or charged by sub cooling method. Winter is here and I can't use the sub cooling method. I sold my scales because I just retired. The problem I'm having is not getting a complete defrost on the outdoor coil. This a Coleman HP split system. Defrost will initiate and continue until it times out on the internal timer on the circuit board. Approx 10 min. Yet there is still about 8" of ice left on the bottom of the coil. New circuit board installed and no change in operation. Condenser fan does shut down during defrost. I added refrigerant but that didn't make any change. Hi side and low side pressures are close to what manual specs.

[Grizzly]

Hi rxtom.
As I am sure you have worked out. Charging by sight glass alone is at best an unreliable method.
Also as a blocked evap will give low charge symptoms.
You are doing the correct thing by wanting to clear the outdoor unit of ice first.

May I suggest you use some form of heat source to as we say "manually defrost" the unit.
Because until you can achieve the correct airflows through the unit.
You are always going to struggle.

I have some Coleman info, so if you let us know the unit details then maybe I or others can assist further.
IE. What controller is fitted so that further defrosts can be initiated.
Plus at a guess I would assume that your defrost interval times may need to be increased.


Good Luck Grizzly.