a/c problem

[hp1020]

ok here is my problem looking for idea's

2 and a half tonn york a/c minni cube running r - 22 freon pressurs at 140high side low side or 65 15 foot line set .. good air flow clean filter ...... unit keeps freezing up any idea's

[Admin]

High side seems low.

What's the ambient?

Check superheat & subcooling.  Sounds like it's low on refrigerant.

[hp1020]

the ambient temp is any where from 77- 86 degrees f

[Admin]

There's alot of variables to consider, but with those ambient temperatures you should have at least a 200 psig high side pressure.  Your low side pressure is probably below 60 psig.  That means the saturation temperature is below 32F, and why things are freezing.

You could have a leak in the system.  It could be a simple trace leak at the service valves.

[hp1020]

will check the service valves for leaks , low side pressure is at 65 psi will raise pressures higher to try see if that fix's problem ....... do you think there is potentail for something to be plugging the metering device?

[Admin]

Usually a plugged MD will cause low suction pressure.
At 65 psig you shouldn't be freezing up. 

You're sure the indoor fan stays running?

Measure the temperature of your suction and discharge lines while the ac is running.
We need to know superheat and subcooling.