CHHN Compressor Leak, Repairable?

[NiNe O]

The casing on this screw compressor is leaking badly between the bearing housing and the motor housing. Is this leak field repairable? I've never had to take apart one of these CHHN's for any reason. Any help would be greatly appreciated.

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http://i849.photobucket.com/albums/ab53/loats/middlemilfordleak_zps0c65b18b.jpg

[moideen]

Hi Nine, welcome to the forum, your Compressor ‘O-ring is damaged. You cannot arrest the leak without dismantling the compressor. This is not the field work. The leak happened on screw side. Check your refrigerant, if there is refrigerant mixing with other gas, usually like this happening.

[FreezerGeezer]

Sorry, but Trane screws are not field serviceable at all. There's special tooling required to get things to line up within tolerance that only the factories have.
As a result the only Trane screw I've ever seen inside was the cut away display in the factory reception in France.

[NiNe O]

Thanks for the replies fellas. Is it possible to expand on those thoughts? When I approach my boss and customer I'd like to be armed with some explicit reasons to justify the heavy costs associated with removal and factory rebuild. Thanks again.

[NiNe O]

Could this result from frequent starts, 10/hr? Addressing this now.

[GHAZ]

Hi take the motor suction cover off and remove the rotor off the shaft
take off discharge cover off and then undo the m16 bolts and slide the complete screw pack out and change the orings, you wont alter any set up gaps

[NiNe O]

Rock on! Why am I taking the discharge cover off? Is there something behind it I need to remove or is it to just free up the front to remove the screw pack?

[GHAZ]

It is less wieght to handle when pulling out the pack.apart from that theres nothing holding the pack

[FreezerGeezer]

Interesting stuff Ghazz, thanks. When I worked @ you can guess where, we were told categorically the screws were not in any way field serviceable apart from things like the solenoids.

NiNe O, I'd love to see some photos of the process if you do it please?

For what it may be worth, Charms (Trane's European chiller factory) started to offer rebuilt screws in about 2006 iirc. If they still do, it may be worth considering for some occasions. I'd be surprised if these weren't offered in the US as well.

[NiNe O]

Absolutely I'll post pics. Quote will be sent to customer today.

[moideen]

Disassembly of the screw compressor may be easy, but assembly is critical. Efficient operation of screw compressor is mainly dependent on the clearance distribution like rotor to housing clearance, interlobe clearance, tolerance between slide valve and slide valve housing….etc.so it is not easy to do at field. More info go to this link.

http://www.achrnews.com/articles/servicing-twin-screw-compressors

http://www.inspection-for-industry.com/screw-compressor-testing.html

http://media.johnwiley.com.au/product_ancillary/6X/04700257/DOWNLOAD/papers.
pdf

http://www.inspection-for-industry.com/screw-compressor-testing.html

[NiNe O]

RTAA-SVB12A-EN is the service bulletin that pertains to this exact repair. Should have checked comfortsite first but I have been busy. This seems to be a pretty straight forward repair, minimal parts and about a day for a couple of guys.

[NiNe O]

Alright, took me long enough to get back here. This chiller wasn't reparied until recently, long story. Anyway, this ended up being a really easy repair. Start to finish, about 4 hours + recovery and recharge time. Most of that time was cleaning surfaces and I made my own suction and discharge gaskets on site.1085510856108571085810859

[kiwi]

Nice work. It certainly did not look like a massive task. The rotor clearances etc can never change with what you have done. These tolerances are set by the thrust bearings and you were nowhere near them.