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CHILLED4
12-11-2007, 07:30 AM
I am having trouble with a cold room. I found the evap coil froze. So i checked if my hot gass bypass was working. It seem like it was stuck closed so i manually opened up a bypass valve to deforst the coil. As the coil deforsted and cleared it seem to be working fine after that. Working @ set point 4c about a couple hours later i had a alarm come in. The box temp was rissing and the coil was fine no ice. so i shut my hot gas bypass valve off and my compressor turned off. So i opened it up and the compressor turned back on but the room was still getting hotter. I cleaned both my coils and reset the system for some reason it went back down to set point and workin. about 7 hours later i got a call that the cold room temp was rising.

Bones74
13-11-2007, 12:13 AM
Well a few things. Are you a licensed Tech? I ask because when you opened up the valve to defrost it for a few hours. You flooded the compressor with refrigerant. Why? Because the comprssor only has a small amount of latent heat in the compressor to thraw the coil off. About 6 minutes or so worth.
Then the coil cool gas is dumped into the evap and changes state then returning in a liquid form. Bad!!
You probably have a bad hot gas valve but I would check the comp now also!:cool:

petrock
13-11-2007, 01:12 PM
What about wet refrigerant.? Maybe freezing up the TX valve.

Grizzly
16-11-2007, 12:47 PM
Hi Chilled4
How does your hot gas defrost operate?
Could you have the situation where you are bypassing the liquid line solenoid valve. When you manually operate the hot gas bypass. Raising the lp/ suction pressure lp switch makes, compressor starts?
Maybe you have liquid line solenoid valve coil down or is there micro switches whithin the bypass valve that are playing up? etc etc.
Cheers Steve.

Bones74
16-11-2007, 07:41 PM
This is typical, A question wanting info and we never hear back.

Toolman
17-11-2007, 12:44 AM
This is typical, A question wanting info and we never hear back.
Your right Bones74 , I always look at there post amounts to see how long they have been around and guess what he has one post ( this one ) . When I read the post I thought why would anyone have a hotgas defrost system on a coolroom ? We used to use and sometimes still do use hotgas defrost on a freezer but rarely . Nothing like a heater that operates when the electronic control stops the compressor for a defrost . Hot gas is crazy , too many things to go wrong . the old KISS theory works a treat
:D
We may never hear from him again not that it will worry me :D