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Lucas
29-03-2004, 05:58 PM
I've got a problem with a small integral chiller c/r compressor. The compressor is an Aspera NE 7213E (R22). The c/r is approx 7ft square (Trimco me thinks). The problem is the compressor is overheating and cutting out on o/load. Condensor clean and condensor motor running ok.

When running the compressor body is very hot.

Its got me confused because once compressor cools and then runs it brings c/r temp down, cycles on stat cutting in and out quite happily, yet a few days later cuts out on o/load again?

Comp valve or overcharged maybe?

I think I'm going to remove gas, check comp and if that is ok, flush system, replace drier, vac out and re-gas to see if that works.

There is no ID label so I'm not sure quantity of R22 to put in. I don't want to overcharge/ undecharge system. The system uses capillary tube. Any suggestions on back pressure I should be looking at and how critical is the charge in a capillary system? At moment unit running around 40psi.
Thanks
Lucas.

bernard
29-03-2004, 06:18 PM
Hi

Obviously its easier to give advise if on site as hand eye can usually find fault. I suspect you have a poor pumping compressor. It will reach temp with door closed but as soon as the customer starts opening and closing door it begins to struggle.Gas charge: you wish to achieve a temp of - 21 so you should be evaporating at around 9 psi on R22. If there is to much gas in the system the side of your compressor will be icing.

Regards

bernard

coriolan
29-03-2004, 07:05 PM
Hi Lucas,
others suggestions: check for voltage on main supply ( sometimes it may fall down ) and amperes; determine if there is any peculiar moment in which the fault happens or if it is random; check for discharge pressure.
Best regards
Coriolan

Latte
29-03-2004, 07:10 PM
Start with the basics, Gas charge.
If there is too much in the system the pot will overheat, this should be easy too see as the suction will frost back badly. System under charged not enough getting back to the pot & overheating it.
Probably best bet if you don't know the system is reclaim, remove drier and blow through with OFN, Change drier, vac & regas. At least this way you should have a better idea whats going on. Also keep an eye on the suction when running & when shutting down, that should give you an idea about how the compressor is. Experience tells me that aspera's dont like running hot.

Regards

Raymond

chemi-cool
29-03-2004, 07:29 PM
hi lucas,

poor compressors aspera, I dont like them, very bad expiriance with them.
its a part of embraco now.

checked your compressor on the catalogue.- its an AC one and not ment to be used in LBP application

so this is the first problem.
the second one is that if its all wet with water running down, you most probably lost all the oil by now and the poor machine is on it way...

compressors must be chosen for the right application.
you can view it at http://www.embraco.com/ingles/produtos/02012.pdf

chemi

iceman007
29-03-2004, 10:37 PM
Hi Lucas

Always difficult to concluse these type of things without being on site, but if you have too much charge in the system, then check the subcooling. If that is OK you can assume that there is liquid leaving the condenser. To eliminate the possibility of non condensables, then you need to perform a simple test.
I have seen cases before where all the symptoms have been there to suggest it's overchaged and it's been because the receiver has been too small, although it's very unlikely. Also, check to see if theres a delta T on the liquid line to amke certain theres no pressure drops across any of the components.The problem with incorrect charge, particularly if it's quite a way off is oil dilution, which won't help the compressor. If, as Chemi says it's on the wrong application, it sounds like it needs changing. I've never believed in short term fixes, and always thought that it's best to sort it out once and for all. Of course if you know the weight of the charge then it becomes easier-if not then if you need to rechrge I would charge to a full sight glass, and make sure the superheat and subcooling are set up correctly.

Best of Luck
James

Lucas
30-03-2004, 04:57 PM
Thanks all.

Removed gas, change drier, blew through with OFN - no blockages, vac out and re-charged with new today. Problem still there compressor hot and sometimes in out on o/load before starting. Won't be long before she packs up.

The plot thickens because today the owner said the engineer previous changed the comp which had apparently seized, for the one now and it hasn't worked well since and the engineer is apparently un-obtainable!

It looks as though Chemi is right and it's wrong compressor type.Trouble is I've no idea what to put on it. No label on cold room or old compressor details available. Does anyone know if the same compressor (Aspera NE 7213E) is also supplied for LBP applications or will it be a different model altogether....................This one has got me going nuts.

Why don't Aspera put what applications each comp is suited for on the label?!?!

It is a chiller coldroom out 2'C in 5'C. No receiver. Evap capillary fed.

Any help appreciated.

Thanks
Lucas

Latte
30-03-2004, 06:03 PM
Lucas,
Try Aspera NE9213E HRP Pt No 208870.
Same Motor MP as 7213 and displacement only .12cc different.
I am assumimg you are still using R22 & this is a high back pressure pot fot chillers.

Regards

Raymond

chemi-cool
30-03-2004, 06:52 PM
hi lucas,

Aspera NE9213E is the same but for comercial use.

I have the feeling from what you say that the original compressor was something else completely.

it looks like you spending too much time there.
you will have to check the cup tube, lenths and diameter.

working temp should be, evaporating -10C, cndensing 45C.
now work out the system capacity.
I will not be surprised if the original compressor was smaller and who ever installed the present compressor, did it because this is what he had in the van.

maybe the old compressor is laying some where in the erea?

chemi

Gary
30-03-2004, 08:32 PM
What is the compressor inlet superheat when near cut out temp?

What is the discharge line temp?

Lucas
13-04-2004, 11:52 AM
Have not returned since gas change etc. Today got call and comp u/s.

Because the Aspera NE 7213E (R22) was an A/C comp I'm just going to put a simular size comp on but LBP type and hope the different type application comp will do for the chiller coldroom. Too much time wasted already. Can anyone tell me the size (HP) of the NE 7213E so I can find a simular size LBP comp to fit.

Thanks

chemi-cool
13-04-2004, 01:31 PM
hi lucas,

as I've told you before, this compressor is for AC application. forget the HP, its not important. check the link: http://www.embraco.com/ingles/produtos/02012.pdf

this is the pdf for these compressors. they calld today EMBRACO but the model is has same number.
check the capacity and go from there.

all the information to help you find a an equal capacity compressor for LBP, is in there.

chemi

Peter_1
13-04-2004, 02:42 PM
What's the type of the Trimco case?
I can ask it at the Belgium Trimco wholesaler.

Peter

Lucas
13-04-2004, 05:30 PM
Thanks Chemi the previous link did not work for some reason but this one is so I will take a look and see if I can work it out.

Peter It is a chiller coldroom (+3'C - +5'C) approx 3m square. No ID plate so nothing doing, I tried Trimco here in the UK but without model they won't/ can't help.

Thanks.

chemi-cool
13-04-2004, 06:05 PM
hi lucas,

do you remeber, when it worked ok, what was the sudtion temp?
it can help to see if the compressor is the right size.

suction temp should about -3C.

chemi

Lucas
13-04-2004, 07:00 PM
Chemi at the time it was -2.

chemi-cool
13-04-2004, 07:09 PM
lucas,

cut off the cup tube and install a TEV instead.

this way you can maintain a proper superheat and have some control of the suction temp.

chemi

Lucas
13-04-2004, 07:16 PM
I understand what your saying Chemi,but compresor does now need replacing, which I want to do as quickly and cheaply as possible. If at allpossible I just want to replace comp and get pout of there. I explained to owner Ididn't really want to get involved but he is desperate...reckons it cost him a fortune for previous engineer.

I had a quick look at pdf and reckon the NE 2134E R22 LBP might do. If anyone would either correct or ok this I would appreciate it....I dont wanna be back and forth for this and there is doubt in my mind as Ihave never had to tryand work out an replacement................ wish I never seen the thing!

Thanks

chemi-cool
13-04-2004, 07:57 PM
hi lucas,

I'm sorry but when I read again the whole thread, I saw that the compressor you had is fine. it is not a LBP that you need but M/HBP is fine, which brings me back to your first problem. it was fine and than got hot.

if the compressor is the right cooling capacity, than the problem is else where and I suspect the cup tube.

I dont like them in a walkin freezer, cant adjust them.

I'd go for a TEV and keep the EN9213E.

chemi

Mark
13-04-2004, 08:42 PM
(in this application)TEV without a reciever :eek: .

Lucas
14-04-2004, 07:41 AM
Yep The NE7213E is AC which is fitted, and the NE9213E is M/HBP and is what I will put on. If it don't work it don't work, I don't like doing things I'm not 100% sure of especially when the owner has been messed around so much. What threw me is in one thre NE7 & NE9 were described as the same comps and would make no difference. With any luck the previous comp was meant to be a NE9 but somewhere along the line the NE7 was fitted without realising.

Ah well we will soon see.

Thanks all.

Gary
17-04-2004, 01:55 PM
Most likely problem is low voltage at the compressor, caused by undersized wiring, burnt contacts in controls, and/or poor connections.

If I had to take a wild guess, I would say burnt contacts in the controls.

chemi-cool
17-04-2004, 04:24 PM
hi gary,

I wouldnt be too sure about it.
such small compressors come one phase and with electric system in europe, ampers drawing is almost half then in the USA.

if we are in a wild guess, then I would say that the original compressor was smaller and the symptoms will be the same.

but lets wait and see.

chemi :)

wesmax
23-12-2004, 07:10 AM
Start with the basics, Gas charge.
If there is too much in the system the pot will overheat, this should be easy too see as the suction will frost back badly. System under charged not enough getting back to the pot & overheating it.
Probably best bet if you don't know the system is reclaim, remove drier and blow through with OFN, Change drier, vac & regas. At least this way you should have a better idea whats going on. Also keep an eye on the suction when running & when shutting down, that should give you an idea about how the compressor is. Experience tells me that aspera's dont like running hot.

Regards

Raymond


Hi could you tell me what is OFN
wesmax

chemi-cool
23-12-2004, 04:11 PM
OXYGEN FREE NITROGEN

You make me feel good that I explain English abbreviations :D

Chemi :)

wesmax
24-12-2004, 04:49 AM
Thanks here we have dry n2 or n2 but that is all , there are other abervations but I will get to them later. Have a good christmas.
wesmax

Abe
24-12-2004, 07:40 AM
OK time for me to add my worth

First, You want M/HBP Compressor, not LBP
Do as what Chem says................Put in a Valve
Did you say no receiver??

Its not an ac condensing unit rigged up is it????? or one of those Marstair thingies......

Replace condensing unit................complete. Put in Le Unite.....
New expansion valve
Bingo
Job done
and dusted............

Ive been through this scenario.........I know
Adding gas here and there, and blowing OFN etc etc.........is fluffing about..........

You dont want the4 customer to think you playing around do you???

And last word.............Perservere............Never give up,
When the going gets tough..............just sweat it out

Gary
24-12-2004, 12:30 PM
Given a few temperature measurements, we could tell what is wrong with this system. Without information all we can do is take a wild guess. Guessing is unprofessional.