If it helps, this unit has a scroll compressor with a DTC. I doubt that matters, but I know someone here has probably come across what ever device this is.

-Fred Raud

 

Also, I call it a 'device' being I can sometimes here it clicking. It is unpainted, so I doubt it is a suction line filter/dryer.

-Fred

 

An in-line check valve?

 

Do all scrolls require a suction check in refrigeration service ?

 

Its a check valve. To prevent pressure from getting back to low pressure control and short cycling. Some scroll condensing units will also have a time delay, both to prevent short cycling.

 

On a WIF the compressor is designed for low temp / low suction pressure. Essentially: big pistons and low horsepower.

During defrost a lot of heat is added to the evaporator. So when beginning the freeze cycle the heat loading, and the resulting suction pressure, can be higher than the compressor is rated for.

So either a pressure limiting TXV is employed - which closes when the downstream pressure / suction pressure is too high. Or, as I suspect in your situation, a Crankcase Pressure Regulator is used. This is essentially the opposite of an EPR valve. An EPR regulates the inlet pressure - never lets it drop Below the setpoint of the valve. Whereas a CPR regulates the downstream pressure - never lets it rise Above the setpoint of the valve.

A CPR is initially adjusted right at the end of defrost - by compressor amp draw. The CPR gets adjusted to limit the compressor amp draw to compressor RLA.

PHM
-------

 

CPR 👇🏻

 

CPR ����

It is definitely not that. I did a bunch of googling, and it appears to be a check valve. I found pics of these check valves, and the one we were working on had the same dimples as the pictures.

 

Magnetic check valve 👇🏻

 

Magnetic check valve ����

Yep.

This is a unit that was installed a year ago and has never worked right. A company came out and changed the compressor(but not the filter drier) and did a pretty ugly job at it. So I guess it is a check valve. But the pic you posted is basically the same as what I found that looks identical to what we were working on. I do not think that check valve is the issue, I just wanted to know what the heck it was. I was very surprised it did not have an accumulator. Supposedly the control board for the Evaporator(not a Beacon I or Beacon II), I was a bit hung over today from Valentines fun last night, so my head was not exactly in the game. All of my notes are in my partners phone being I have not been issued a phone or tablet yet(I just started this company a few days ago). The manufacturer is sending us a new controller. I was surprised they arent sending us an EXV, sensors, transducer, etc being they have been having issues since the install. Oh well. I guess Monday or Tuesday when we change that controller, and see what happens. After doing the checks that the engineer from Russell wanted us to do, they are certain it is the controller. I have my doubts, but I am not an engineer.

-Fred

 

The problem is scrolls suck for refrigeration.

 

What's going on with the system ?

 

Short cycling. When we showed up I did notice the filter/drier was half frosted, and assumed it was plugged being someone replaced the compressor and probably did not use good practices while doing so. Especially it was very obvious that it was not replaced.

I can hear the EEV(or EXV, I use the EEV being that is Russels part name for it, but it kept pissing my partner off when I called it an EEV) working, and going through the menu on the controller it says it was at 62%. When checking the voltages on the board, between pin 1 and 3, it wasnt getting close to what the data was given to us(under 1vdc was what we read), so their engineer told us that board is bad. With a long night for V-Day, 4.5 hrs driving time, I wasnt quite in the mood to stick around when tech support closed. I know that is not a good excuse, but it is what it is, and definitely not the way I normally do things.

We tried to set cut in and cut out to 25/5, but it would keep dropping into a vacuum so we ended up messing with the LPS to keep them running until we can get back. Also disconnected the DTC solenoid(not my call on that one) despite it appearing to be working correct. Top of the compressor was 185f, the DTC is rated for 193f and it was still feeding liquid into the compressor. 8f difference is not awful, but I doubt that is our issue.
I really would have preferred to go by myself, but they have me riding with a guy for the first few days to become familiar with their paperwork. He is a sharp guy, very experienced(supposedly 30 years experience vs. my 9 years), but we do things different. And I, being the new guy, just followed his lead.
The filter drier we replaced was easy to blow through, so I doubt it had a restriction. But being we had to sweat in some Schroeder valves, and the compressor had been replaced, I considered that good practice.

The box was at 7f when we left, but the super heat was still hunting pretty hard. EEV going from 10% to 62%, dropping into a vacuum every few minutes, and being the engineer from Russell said he was certain it was a bad board(we went through the normal checks SH set point, measured SH, and gauged up on the Evaporator and confirmed the board was measuring correct. Refrigerant type was set to R448 in the controllers firmware.

Sorry I dont have more information, but I figured I'd chat it out over the weekend until we get this board being my gut is telling me we will have to tell the customer that we need more parts.

Ugh

-Fred

 

Hang on a sec. Just because there is an 'un-diagnosed' problem or problems should not be a/the reason to replace a lot of parts for free, in-warrantee. Something somewhere is wrong in KNOWLEDGE-ville. I think.
So, hows bout YOU putting your butt/reputation on the line. But thats the boss/service manager who decides on that line of thinking.

If you get shuffled off to another job, I would find out who was sent there to see 'whats what' and Q him on what he finds out.

 

The tech that changed the compressor was from a different company, and no clue who. Not that it really matters at this point being they are not the ones working on it.

And I agree, I normally do not like to pull out the parts cannon until everything is good, which is why I am here at 11pm with it still rattling in my head.

-Fred

 

Can you supply a russell condenser number and perhaps tell us what the system is doing?

The fact that the compressor was replaced but not the filter dryer says a lot!

Who does this??

As far as the frosting on the suction side, its possible this could be some type of suction accumulator, a compressor suction load control or CPR will not freeze, it’s purpose is to limit the amount of refrigerant volume or crankcase pressure as to not overload the compressor, if its a device on the liquid line, frosting could be caused by restriction.

*Scroll compressors work just fine for refrigeration if the oil return and the superheat is correct and the unit is sized and installed correctly 👍

Was the compressor a burn out, was the system flushed thoroughly?

Not to be funny at all but reading your post this has not worked correctly from the beginning, I would suggest spend the time and check your expansion valve , depending on the expansion valve, in the liquid ( hi pressure) or feed side there is usually a small very fine screen about #100 mesh, that if there was a burnout or contamination it could have ended up clogging the screen.

Some 90* exp valves have a removable screen and most of the straight through valves have the screen inserted in the liquid side just past where you braze or stay bright your copper liquid line

Your going to have to thoroughly go over this system and unfortunately that takes time in order to make sure its right.

 

Can you supply a russell condenser number and perhaps tell us what the system is doing?

The fact that the compressor was replaced but not the filter dryer says a lot!

Who does this??

As far as the frosting on the suction side, its possible this could be some type of suction accumulator, a compressor suction load control or CPR will not freeze, it’s purpose is to limit the amount of refrigerant volume or crankcase pressure as to not overload the compressor, if its a device on the liquid line, frosting could be caused by restriction.

*Scroll compressors work just fine for refrigeration if the oil return and the superheat is correct and the unit is sized and installed correctly ��

Was the compressor a burn out, was the system flushed thoroughly?

Not to be funny at all but reading your post this has not worked correctly from the beginning, I would suggest spend the time and check your expansion valve , depending on the expansion valve, in the liquid ( hi pressure) or feed side there is usually a small very fine screen about #100 mesh, that if there was a burnout or contamination it could have ended up clogging the screen.

Some 90* exp valves have a removable screen and most of the straight through valves have the screen inserted in the liquid side just past where you braze or stay bright your copper liquid line

Your going to have to thoroughly go over this system and unfortunately that takes time in order to make sure its right.

I wish I had more information, but as i mentioned, it all was put on my co-workers phone until I get a phone Monday. As far as why the compressor was replaced, I have no means to find out. All we were told was this unit was purchased last year, and there was a leak at the rotolock, and a few Schroeder valves. The leaks were rectified today. The reason the Schroeder valves were replaced was they were 'stripped'. I was able to get the Schroeder valves out, and they were covered in sealant that was blue, and not Nylog.

Again, the reason for my post was to identify that check valve, and keep my mind running in circles in how i would have handled it different had it been my call.

Being this has an EEV, there is no screen. Well, if there is, I did not see it where i normally see one on a TXV.

-Fred

 

Again scrolls suck for refrigeration.
Ask me how I know ?
For one Copeland has a bulletin explaining how the discharge check valve will leak.
This can be problematic because of the reverse rotation it creates.
Hence the reason for the bandaid time delay.
Additionally those cheap solidstate delays are as cheap as those peanut switches.
I've replaced multiple scroll compressors from different equipment manufacturers under warranty or just out of warranty for the exact same issue.

 

In response to VP99s post…
Speaking of the cheap time delays on scroll compressors, we have had frequent enough failures I’ve considered sourcing the old ice o matic dip switch timers to out in their place- anyone ever seen one of those finish timers fail?

 

What you’re referring to is a check valve. I have seen failures of boards, and weirdly enough the wiring harnesses, on brand new HTPG Econet systems. If you aren’t getting the correct VDC out of the board I would suspect that being the problem. However I have seen the Sporlan EEV’s fail closed. Even though the board says it’s open the condensing unit still cycles off on low pressure because the valve actually isn’t opening. Also ensure there isn’t a time delay installed on the condensing unit. The board has its own time delay, and if it doesn’t see a change in SH in a certain time frame it will close the valve down.

 

Have had alot of trouble with that in Heatcraft Inteligen units. Econet hasn't been as bad of a problem for us. EEV wouldn't respond quickly enough and low pressure control would cut out. Time delay in the cond. unit would hold the compressor off long enough the board would close the EEV down and when it reopened after a few minutes it didn't open fast enough again and it got locked into this viscous cycle. Solved it by putting on a low pressure switch bypass timer (on delay timer). Locked the compressor on for 15-20 seconds or so when the LP control first cut-in.