On Mon, 6 Oct 2014 07:40:33 -0700 (PDT), Richard Kollmann
wrote:

On Thursday, October 2, 2014 3:14:32 PM UTC-4, Sir Gregory Hall, Esq. wrote:
I can't figure it out. I keep having to let refrigerant out of my Adler Barbour. It runs great with the suction-side pressure set at 15 psi. But, every month or so it will commence to cycle off and on after being off for the night. I put a gauge on it and the suction side pressure is in the beginning of the red range(55 psi). It turns on and the compressor starts compressing, the pressure starts going down but it only gets to about 45 psi until the compressor *clicks off* and the voltage gauge goes up a volt or two because the load comes off the circuit. Then it turns itself off and back on and the compressor starts to compress again and the pressure goes down to about 45 psi, then it cycles off again. So, I let out some pressure until it only starts out around 45 psi and it will finally keep compressing until it draws down the suction side to about 15 psi where it stabilizes. So where does the extra pressure come from. I've had to let out ten pounds of pressure about half a dozen
times this summer. I can understand leaks but this is ridiculous! -- Sir Gregory

An Adler Barbour old fixed speed or new variable speed CU models are serviced with 80 to 120 grams of refrigerant. Trying to determine correct refrigerant charge when compressor is not running is of no value as ambient temperatures of complete system are likely never going to be the same pressure.

The important indicators of an AB refrigeration unit's performance is how much amperage it is drawing, frost covering of evaporator and no frost on return line towards compressor.

Once a servicing gauge is connected to one of these very small systems the chances are the refrigerant's purity is probably compromised. If refrigerant is still pure suction pressure will after 20 minutes compressor running time will read 6 to 8 psi for 134a refrigerant and 8 to 11 psi for R12 refrigerant. If thermostat is set for refrigerator temperatures many hours later suction pressure will be the same or a few psi lower if evaporator is very cold.

Once low pressure is correct and frost coverage and amperage is not correct you will know there is a problem with condenser cooling or contaminated refrigerant. As Skip mentioned on another manufactures refrigerant flow problems can not be ruled out. Moisture freezing in refrigerant is possible if refrigerant is contaminated. It is unlikely that Skips problem with refrigerant flow will occur on an AB system.

There is a special section on Refrigerant Charging on my web site covering Adler Barbour Danfoss BD compressors.



Thanks, I might just have to try vacuuming the damned thing out and
putting new r134a into it. It could be that it gets a blockage from
time to time which could conceivably drive up the suction pressure
so high that the high pressure cut-off switch cuts in.

I know somebody who has a vacuum pump I can borrow. I suppose a little
water vapor in the system could wreak havoc. I tend to be sloppy with
connecting the little can of r134a and I never even thought about
purging the supply hose.

--
Sir Gregory