Frost back on 3hp copelamatic 408 freezer

[crisrs]

I would like to know why on some reach in freezers I am getting frost back all the way to the compressor.3 hp system with receiver charged until sight glass has no bubbles. Isn't the TXV supposed to control liquid in the suction line.

[R12rules]

What's your superheat back at the unit? This temp will tell you whether or not you are getting liquid floodback to your compressor. Or not.

Jus cause the line is icing, doesnt mean it's liquid flooding back.
It's probably just cause it's so cold.


You want thirty degrees, superheat, back at the unit.

[frozensolid]

TXV controls superheat.

[gbfromsd]

Superheat.

if you want a box at zero degrees, then obviously your coil must be colder - say 10 degrees below zero. Now, if Copeland asks for 20 degrees of superheat at the compressor then that suction temperature needs to be
-10degrees plus 20 or plus 10degrees. That suction line
better frost or we're living on a different planet.

[crisrs]

The part I don't get is two freezers next to each other at box temp of -10 F both air cooled with 408 gas and one ices up to the compressor and the other doesn't

[condenseddave]

I think you need to contact an experienced commercial refrigeration technician for assistance.

[crisrs]

Thanks for the tip

[Freezeking2000]

I think the freezer with no frost will be burning up a compressor before the one that has some frost.

[R12rules]

Originally posted by Freezeking2000
I think the freezer with no frost will be burning up a compressor before the one that has some frost.

I agree.


Before I came to this site ... I had a lot of crummy ideas in my head. (DiceMan ... dont even go there!)

Now it all comes together in a kind of harmony. It all makes sense.

And I see others finding the same answers.


There's a lot of "ol wives tales" in our industry about what is right and what is not.


This is a fantastic site!!!

BOSS..... Thanks Again!!!!!!!

[rayr]

Originally posted by crisrs
Isn't the TXV supposed to control liquid in the suction line.

If this is what u think, your customers are in a lot of trouble. Do what dave suggests, get an experiended tech for assistance. RSES offers Refergeration 1 & 2 courses. An execellent option for u.

[refer dude 2479]

Originally posted by R12rules

Jus cause the line is icing, doesnt mean it's liquid flooding back.
It's probably just cause it's so cold.

This reminds me of a conversation I had with an appentice about 15 years ago. We went to service a freezer plant that I worked at regularly. Freezer about 1/2 the size of a football feild. 5 Carrier 5H120's. Box temp -10. He freaked and wanted to adjust all of the tx valves cuz there was ice on the suction service valve.

Had the same talk about suction temp and superheat at the compressor. If the gas is below freezing tewmp there will be ice. End of story. you need to know the actual temp to determine if there is a problem..

[rayr]

Some serious education is also needed in the area of DEW point.