Bad Valves?

[newgage]

Coplemeic Model LAL 0310 tac S/N 00I15817cc

Three HP compressor serving a freezer. R502.

Customer was told by refrigeration Friend that windings were gone and compressor needs to be replaced.

I checked the unit out and found the three pase compressor to be electrically sound. I did not megger as I do not have one yet. Windings not open, shorted to ground, or shorted across windings. Incomming voltage good.

History was that unit had leaks,theywere all repaired, then charged. unit ran for 24 hrs then stopped running on two seperate occasions and they lost product. Unit has been off since then.

On my inspection I cound hear and feel crankshaft start and run as long as i had power to compressor, yet it was doing absolutely no work. Rated at 10.9 amps and drawing 4 amp.
No change at all in suction pressure. Head pressure could not get since shrader was screwed and pissed out gas as soon as I loosed cap.

First time I have come across this type of problem.

I suspect bad valves.

Any suggestions on what to bring when I go back to isolate the compressor and pull the valve plate?

I do intend to replace high side access. I am thinking I should cange the oil since the system has been neglected. Dryer will get changed also. Is it worth it to repack a leaky suction service valve stem or should I relace the whole valve?

I also am unsure why there is what appears to be two sets of three prong winding terminals and an overload. What is the second set of terminals for?

[k-fridge]

Sounds like a broken crank to me, motor running but not pumping.

[newgage]

I thought about that too but operation was very quiet and I would have that there would have been more noise. I guess I cant tell untill I return.

[icemeister]

Pull the head and inspect the valves. If they look OK kick it over and watch the pistons not move.

I believe this compressor has T1,T2 and T3 on one block and the connections for the external overload on the other Fuseite terminals.

Try tightening up the packing nut on the suction service valve, If that doesn't work replace the whole valve.

What's this shrader high side fitting you're talking about? Doesn't this compressor have a discharge service valve?

That compressor is only 5-6 years old.....way too young to die like that. Look carefully at your system to find the cause.

[hussmantech]

Speaking of valve plates...
Does anyone have a cross reference for copeland compressors and their corrosponding valve plate?

[icemeister]

Originally posted by hussmantech
Speaking of valve plates...
Does anyone have a cross reference for copeland compressors and their corrosponding valve plate?

Since Copeland stopped printing stuff like that and just having it available on line you kinda have to have a laptop in the truck these days. I used to keep old copies of wholesaler catalogs that had that type of info but now I just go look up the stuff I need at Copeland's (Oops.....I mean Emerson's) site.

Maybe Rocket will come along and have something you can print out for yourself.

[rayr]

Valve it off and pull the head before you order valve plates. My money is on broken crank. Most of em do NOT sound like an old Ford ready to throw a rod. Just sit there and hummmmmm and do NO work.

[rocket]

you can look at this link for VP info
http://www.orrbilt.com/parts.htm
you can use this reference on reed compressors but
be careful on Discus, many changes made

most damaged valve plates caused by slugging, changing valve plate does nothing for other parts damaged, like broken crankshaft. Changing a valve plate without knowing what broke it is almost always a waste of time

depending on conditions, amps can be from 7.7 to 18.1, so 4 amps probably means bad valves
if you are reading amps from nameplate (RLA) you are barking up the wrong tree, get a performace sheet from Copeland to see amps. If you are not sure what a performance sheet is, you can search this forum for many explanations.

in your case your valves are probably bad, but the possibilty of broken crank is also high, not checking may make you "eat" the valve plates

[newgage]

Thanks for all the great input!

I dropped by the site today and pulled the head. Valves looked ok to me. No evidence of overheating nothing cracked or broken. Pulled the valve plate, tried to depress the pistons but could not. Started unit up and there was no movement at all. Definately sounds to me like a broken crank.

Did not see a crankcase heater.

Have to to to see if it worth it at all to rebuild. Customer with low profit margin. Not a lot of money to spend but the work gives me great experience.

will post more later

[k-fridge]

Originally posted by newgage
Thanks for all the great input!

I dropped by the site today and pulled the head. Valves looked ok to me. No evidence of overheating nothing cracked or broken. Pulled the valve plate, tried to depress the pistons but could not. Started unit up and there was no movement at all. Definately sounds to me like a broken crank.

Did not see a crankcase heater.

Have to to to see if it worth it at all to rebuild. Customer with low profit margin. Not a lot of money to spend but the work gives me great experience.

will post more later

If I'm not mistaken that is one of the compressors that had serious lubrication problems when changed over to use blends like R-408 or HP-80. It was so bad they would usually break a crankshaft or rod sometimes within hours of converting. Copeland started putting an internal oil pump in them to solve the problem, the models with the pump are evident by two 5'16ths hex head screws on the end of the body (head side). If your compressor is not one with the oil pump I would not try and rebuild, swap it for at least a re-man unit with the pump. If you will be using R-408 or HP-80 I would use AB oil. You might want to use POE and convert to R-404 while you're at it but you need to flush the lines and the evap with a product like the Calgon stuff for that purpose.

[newgage]

k-fridge
Good thing to know about the oil return problem.

That aids my decision about rebuilding this compressor or buying a rebuild or going brand new.

I cant get a cost on a rebuild until tomorrow. I wonder if rebuilding this one will be worth it costwise. For my own interest I would love to open it more to see if it was rod or crank. Now that you mention the oil return problem I will check with the supplier to see my options.

I took a quick look at the txv and noticed it had been there for some time and it might be an idea to change them out.

I also told the customer the remote condensing unit on the roof needs work if I were to procede. One fan motor out of three is missing and the next one in line has worn bearings and is soon to go. To top if off the back and sides are boarded up for "noise concerns". ie bad bearing

Customer told me when the previous work was done they let it run for 24 hrs and it ended up tripping the breaker.

Customer said he spent a lot of money on refrigerant and it would be nice to use what I have left in the receiver. At this point I dont know what it is, nameplate says R502. I will try to see if customer has record of it being changed recently.

I might go with 404 since that is what I seem to carry more of.

[Edited by newgage on 05-22-2006 at 09:03 PM]

[k-fridge]

Originally posted by newgage
k-fridge
Good thing to know about the oil return problem.

That aids my decision about rebuilding this compressor or buying a rebuild or going brand new.

I cant get a cost on a rebuild until tomorrow. I wonder if rebuilding this one will be worth it costwise. For my own interest I would love to open it more to see if it was rod or crank. Now that you mention the oil return problem I will check with the supplier to see my options.

I took a quick look at the txv and noticed it had been there for some time and it might be an idea to change them out.

I also told the customer the remote condensing unit on the roof needs work if I were to procede. One fan motor out of three is missing and the next one in line has worn bearings and is soon to go. To top if off the back and sides are boarded up for "noise concerns". ie bad bearing

Customer told me when the previous work was done they let it run for 24 hrs and it ended up tripping the breaker.

Customer said he spent a lot of money on refrigerant and it would be nice to use what I have left in the receiver. At this point I dont know what it is, nameplate says R502. I will try to see if customer has record of it being changed recently.

I might go with 404 since that is what I seem to carry more of.

[Edited by newgage on 05-22-2006 at 09:03 PM]

Well, here's another reason I just realized. A LAL is a medium temp R-12 compressor. For a R-502 freezer you need a LAH (low temp) or LAC (extra low temp). Better change it, get one of those comps with the oil pump and charged with POE if you're going R-404.

Here's you an application chart;
http://www.orrbilt.com/cope1.htm

[rayr]

[QUOTE]Originally posted by newgage

I took a quick look at the txv and noticed it had been there for some time and it might be an idea to change them out.

Why would you want to change a TXV just because ""it had been there for some time""?? That is ludicrous.