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TraneDave
08-20-2010, 11:55 AM
Hey all, I am working on a Hobart DAF2 freezer that is acting like a refrigerator.

I got a call on it yesterday and when I got there the suction line was iced up and looked to be getting some liquid back to the compressor. Factory charge is supposed to be 21 oz and I pulled out 2 pounds 13.25 ounces!!! I weighed back in the 21 oz and the compressor ran quite (compressor noise was the complaint) and at 38 degrees when they want it to run more like -20 to 0 degrees. This could explain the overcharge, somewhat. When I got there yesterday, the box was at -10 degrees.

The thermostatic adjustment (Cooler with arrow knob) is set at the maximum of 9 and the compressor doesn't kick out until the adjustment is turned to off. Could this guy be the culprit?

I am open to any thoughts and ideas.

Thanks,
David
EugeneTheJeep
08-20-2010, 12:49 PM
Operation pressures? Amps as compared to RLA? Will it pump down into a vacuum and hold with the power off? Last time I worked on one of them the cap tube was replaced with a TXV and a site glass, been running like a champ now for a good 5 years. Previous to that it used to eat alot of compressors.
TraneDave
08-20-2010, 12:57 PM
Operation pressures were (as memory serves) about 5 psi suction and something around 200 psi. Didn't take amp readings. No indication of leak...held vacuum.

One day it was fine the next it was like this (as I am told) someone added charge and got the box temp correct but the suction line was ice when I got to it yesterday and the compressor was really loud.

Thanks,
David
EugeneTheJeep
08-20-2010, 01:39 PM
What kind of refrigerant? If it is 404 or 502 it sounds like a restriction. I cant hear the compressor noise, and don't know the amps?
TraneDave
08-20-2010, 01:59 PM
Yep. 404A. Haven't gotten back for amp draw yet. Too many other problems on campus.
EugeneTheJeep
08-20-2010, 02:18 PM
Yep. 404A. Haven't gotten back for amp draw yet. Too many other problems on campus.

With that low of pressures, it is pretty much a restriction any ways.
simbamolly
08-20-2010, 03:15 PM
I think if it were me, I would pull the charge,change the drier,pull a good vacuum(with a micron gauge) and recharge with an exaxt charge of virgin refrigerant. Then test amp draw,pressures, and frost pattern.
pdrake65
08-20-2010, 04:55 PM
Operation pressures were (as memory serves) about 5 psi suction and something around 200 psi. Didn't take amp readings. No indication of leak...held vacuum.

One day it was fine the next it was like this (as I am told) someone added charge and got the box temp correct but the suction line was ice when I got to it yesterday and the compressor was really loud.

Thanks,
David

Cap tube? What is your superheat? System was probably over charged to get suction pressure up.It is holding temp now?