Air Conditioners: Is the Compressor Too Big?

Hello Dan:

In short no, you're going the wrong way, you could probably get away with the combination utilizing an expansion valve, although it likely would be inefficient. If anything you need to exchange more air through the evaporator so a higher fan speed would be beneficial.

I assume that the compressor is not an open type but a sealed unit (hermetic) type. In which case it requires a certail amount of cold refrigerant to cool the motor windings. When the imbalance is, as you suggest, without a TX valve, you will incrfease the superheat of the returning refrigerant beyond 11 deg F and the electric motor windings will overheat. A TX valve will control superheat. As the imballance is in this case minor you will probably get away with it. If you have iceing problems with your evaporator, you can correct this by using a crankcase pressure regulating valve or an evaporatot pressure regulating valve assuming that the evaporator air quantity is at it's peak.

Good luck

Phill

You need to check btu ratings on all items in the system.
In the past many condensing units were rated as 2 ton
but had a 1 1/2 ton compressor to claim better efficiency ratings
but they had to have a 2 ton cooling coil and 2 tons on air flow
to get 2 ton performance
If you actually have a 2 ton condensor w 1 1/2 compressor w a 1 1/2 coil

It should work
Some compressor mfgs took tons/hp out of their model numbers and show btu rating

I always try to get enough air flow to get 20 degree drop across the cooling coil
72 in 52 out but sometimes the system just won't do it with low air flows

USA Mfgs suggest on a/cs 400 cfm per ton or coil defrosting will be your next problem

Cheating on coil sizes causes higher td's and higher electric bills
Adding back pressure regulators will stop frosting but adds more pressure drop

Why give it to the electric company?
JR

If I understand you. You wish to use a 2 ton condensing unit with a 1.5 ton evaporator/ air handler. It will sort of work, but not very well. You will have problems with the suction/ vapor return line vapor pressure. It Will not be efficient and it will not last long.