Compressor flooding

[fr420]

I have a walk in box, Went to job yesterday found compressor flooding. Check to make sure evap was clean and fan going right way, all good. Tried to adjust expansion valve and nothing!! Went back today put in new valve and same thing, still flooding. Is it possible my new expansion valve is bad ??? It's an old R-12 system that has 414b in it now. It seems that refrigerant is just blowing by the valve, I cant even clear the sight glass, no matter how much refrigerant I put in. Am I missing anything?

High side pressure was about 112 and low side was about 38. Ambient temp about 64

[cmclifton]

Sure that compressor is pumping efficiently?

[jpsmith1cm]

Sure that compressor is pumping efficiently?

I'm not the only one who caught that...

How about a full set of system readings?

Ambient temp, suction and liquid pressures and "flooding" aren't even close to enough to help you with this system.

[fr420]

Sure that compressor is pumping efficiently?

If the compressor was in efficient it would be hot or at least warm, not a ball of ice, correct? I did check liquid and suction line temps, don't remeber exactly what they were, but according to pt chart I had no superheat, and about 15degrees of sub cooling if that helps. and the box will not come down in temp at all, so I basically am not getting any heat transfer across evap at all.

[ryan1088]

Assuming you have the bulb in the right place and insulated well? We do need some numbers to look at. Also does this have some type of head pressure control?

[icexprt]

Is there a heat exchanger mounted in the liquid/suction line? Have seen them leak internally and bleed liquid right into the suction line. Those were fun to diagnose!

[jpsmith1cm]

Your low side was 38 pounds which equals 47 degrees and you compressor was "a ball of ice"?


Something is very fishy here.

[Tommy knocker]

Did u pump down and change valve or pull charge? I'm with JP on the ice ball at 47 SST. Are you maybe grossly over charged?

[icexprt]

Does the system have a heat exchanger installed?

The more I think about this, the more convinced I am that you probably have a heat exchanger on that system and it is leaking internally, dumping liquid straight into the suction line! Has anyone else ever seen this? Anyone agree?

[Capz]

Does the system have a heat exchanger installed?

The more I think about this, the more convinced I am that you probably have a heat exchanger on that system and it is leaking internally, dumping liquid straight into the suction line! Has anyone else ever seen this? Anyone agree?

Yea, thru the TXV equalizer but the SH would be way low measured at the compressor and way high measured at the evap but wouldn't one visually see this while troubleshooting?

[Capz]

Oops, you said heat exchanger. Never saw one leak internally, only externally.

[coolerik]

Ive seen an hx accumulator leak internaly, tricky one, im pretty sure there is a thread or 2 about that on here somwhere, but im horrible at finding stuff

[fr420]

Your low side was 38 pounds which equals 47 degrees and you compressor was "a ball of ice"?


Something is very fishy here.

Your assuming SaT. vapor, but if I'm flooding wouldn't that be sat. liquid? then the temp is 32degrees. Now evn though I was flooding I didn't have a clear liquid line sightglass, so I did add some refrigerant to see what would happen and my pressur did increase there for so did the suction temp, but originally my suction temp was about 25 degrees when it was icing up

[fr420]

there is no heat exchanger and there is no external equilizer.

Trust me I've been doing this for a long time and I'm just as confused as you guys. I know i doesn't make much sense, just looking for Ideas, because this has me stumped as of right now. I'll be back there this weekend. First thing I'm doing is taking entire charge out and re-charging to make sure charge is proper (I did a lot of adding and pulling of charge when I was there the other night) then I'll take full set of readings.

[fr420]

Assuming you have the bulb in the right place and insulated well? We do need some numbers to look at. Also does this have some type of head pressure control?

Insulated and in proper location, no head pressure control, but condensor is in a basement. the basement does get a little chilly in winter about 60degrees, but has never been a problem in past

[jpsmith1cm]

Your assuming SaT. vapor, but if I'm flooding wouldn't that be sat. liquid? then the temp is 32degrees. Now evn though I was flooding I didn't have a clear liquid line sightglass, so I did add some refrigerant to see what would happen and my pressur did increase there for so did the suction temp, but originally my suction temp was about 25 degrees when it was icing up

So, you're now claiming a subcooled suction line?

32F SCT (this is wrong, but I'll play along) with a 25 degree suction line?

5 degrees suction subcooling?



Your readings are wrong, friend.



icexprt,

I've seen suction/liquid heat exchangers blow out and leak through. Not very common to see that particular part on smaller equipment like this.

[fr420]

So, you're now claiming a subcooled suction line?

32F SCT (this is wrong, but I'll play along) with a 25 degree suction line?

5 degrees suction subcooling?



Your readings are wrong, friend.



icexprt,

I've seen suction/liquid heat exchangers blow out and leak through. Not very common to see that particular part on smaller equipment like this.

I dont know if you mis-understood me or your just an arrogant prick. But never once claimed I had a subcooled suction line. I said temp was originally 25 and rose to 32degrees as I added some refigerant.

[2sac]

Is the box full of turkey ice cream and is your name Feng?


Did you do a pumpdown test and check amps vs nameplate? Also, I know I've seen somewhere 414b do not to charge by sight glass.

[jpsmith1cm]

I dont know if you mis-understood me or your just an arrogant prick. But never once claimed I had a subcooled suction line. I said temp was originally 25 and rose to 32degrees as I added some refigerant.

You said that you measured a 38 pound suction line with 414b, then disagreed with me when I pointed out that it was impossible for ice to form at that condition. (47 degrees Saturation Temp)


You said that you thought that you should use the bubble point (liquid side) for the suction line (32 Saturation temp). This is incorrect, you would use DEW point for the suction side of the system.

So, I'm using what you've given me of your readings and some simple math to point out why I think that your readings are erroneous.

You can call me an arrogant prick if you like, I've been called worse and I'm still standing.

What I do know is refrigeration, and something here isn't adding up.

[2sac]

icexprt,

I've seen suction/liquid heat exchangers blow out and leak through. Not very common to see that particular part on smaller equipment like this.

I've seen a number of them over the years, only on R12 systems