Fridge compressor/condenser unit replacement - or repair?

[skyflyer]

The original (19 year old) Adler_Barbour compressor/condenser unit of my new (to me) boat, is located in an aft locker which is not totally watertight and anyway has clearly been used to store wet gear etc, as well.

As a result the steel base plate on which it is all mounted (which in turn is bolted to a wooden shelf) has almost completely rusted away. The control unit (box of electrics!) and fan had completely detached. Amazingly, despite all this, it works. I have cleaned away all the flaky rusted material and used GRP to glass it in place onto the wooden shelf, at the same time reinforcing the other attachment points.

However, realistically I think I have to face the fact that it's days are numbered!

A repair might be possible if I can remount everything properly on a new metal (or even wooden) base plate, but to do this I will need to disconnect the unit from the rest of the refrigeration system

The unit is fitted with what i think are self sealing quick connectors, (large conical fittings with hexagonal spots for a spanner to grip) but I have no idea whether these will do their job after having remained sealed for 19 years. Am I on a hiding to nothing? Will they most likely be corroded shut forever, necessitating taking a saw to the pipes?

Even if I can get it off, there has been a suggestion that if I cannot repair it (or maybe even if I can), or decide to fit a new compressor/condenser unit, this should not be done without fitting a new evaporator in the fridge itself and appropriate piping due to the risk of contamination of the refrigerant with small particles. Is this just sales bullshit to make me spend more?

If I have to cut the pipes, is it a simple soldering task (or maybe they are compression fittings?) to fit new connectors? i.e. a regular 'plumbing' job, or does the heat of the compressed fluid preclude the use of solder?

Any guidance from someone who has done similar or is a professional in this area would be most appreciated.

Thanks

 

[duncan99210]

The business of connecting up and re gassing fridges is an entertaining one. You need not only the correct fittings to put new refrigerant into the system, you also need a supply of the right gas. So, first off you'd need to identify what your existing system is filled with and find out if you can get hold of that today or if there's a suitable replacement available. I know that's only part of the answer to your question but it's a show stopper if you can't regas it, as I understand that the compressor and plate both have to be compatible with the refrigerant used.

From my limited experience, the joining pieces are for the most part one time use only. However, some older types were reusable but after 19 years that may not work too well. In any case, you'd probably need to check the system was properly gassed after taking it to bits and reassembling, so problem one still applies!

If it works, the tidy it up as best you can and let it carry on. Perhaps get a fridge man in to have a look at it and advise on the way ahead. If you do need a new compressor, you'll probably need to replace the plate as well for the reasons above as well as the problems with contamination. When we had a fridge man look at our setup here in Greece, he refurbished the compressor, fitted a new plate and regassed the system. It has improved things immeasurably the fridge is cold for the first time in years at about half the cost of a new system.

 

[septiclecky]

Being 19 years old it might have R22 refrigerant gas which is being phased out so you may nee to look at getting anew system

Have a look at this

http://www.airconsolutions.co.uk/R22/what-is-r22/

 

[superheat6k]

The fittings sound like conventional refrigeration 'Flare' fittings. 19 years ago was 1996, around the end point for R12. By then R134a was in wide use for smaller fridges, and if the kit was new then I would expect R134a, which for now is still current. I would be surprised if your system was anything else.

Because the copper pipe doesn't corrode and the system is inert the internals will likely be pristine - until you open the system when the gas will go and air and in particular airborne moisture will get in.

For me venting your fridge would be illegal, but strangely enough under the Environmental Protection Act 1990, not for you as a private citizen, to whom last time I read it it did not apply. I cannot condone that you do vent the system.

When you reinstall it it isn't just a case of re-doing the flare joints, which are a simple flaring of the end of the copper tube, which is then hard sealed against a conical end of the threaded fitting by the associated nut. The malleable copper makes the joint tight. Mostly they will go again at least once. A smear of loctite 577 helps them reseal.

But the next thing is to get the air back out, and the only way to do this properly is with a vacuum pump. Ideally the system joints should be pressure tested first at working pressure, but realistically for a small system the joints are bubble checked with soapy water after the re-charge. If you cannot obtain a vac pump then a purge will remove a good deal of the air, but the result will not be perfect, and again I would be breaking the law in doing this.

This last part is difficult to explain in a short thread, and would under the terms of the F Gas Directive be illegal for anyone not qualified to do, although Halfords still sell R134a aerosol style refill kits for Joe Public to use. If you can identify the gas as R134a one of these kits would likely recharge your system. The extra oil they include probably will do no harm, but will likely be a different grade to the original oil fill. Risk here for an old bit of kit is minimal.

If you want some more info PM and I will send you some links to useful reference manuals.

 

[skyflyer]

IIRC the gas is R134a, according to a sticker (i'm working from memory here, but it certainly wasn't R22 and i actually thought i remembered R1534 which probably doesn't exist so R134a seems right)

The connectors look similar to these (obviously i can't say exactly if they are the same inside as i haven't disassembled them)

 

[oldgit]

Several people I know have decided to go down the path the path of repair regards non functioning fridges,one chap had two fridges on his boat fail one after the other..
All the repairs failed shortly after either due to further leaks or other mechanical failure..
Buy new one and cut out the aggro of taking the old one out,taking it to who ever will have a go at fixing it,getting it back,reinstallng etc. etc.
Probably approaching half the cost of new one.

 

[Heckler]

Being 19 years old it might have R22 refrigerant gas which is being phased out so you may nee to look at getting anew system

Have a look at this

http://www.airconsolutions.co.uk/R22/what-is-r22/

R22 was used in aircon systems in buildings and window units. I never ever came across it in fridges. If anything he could have, possibly, R12 in it. That was phased out at about the time his boat was built.
If it was me, I would make sure that I could afford the downside in monetary terms and availibility terms and have a go at cracking the unions. If it doesnt leak, fine, get it out, clean paint refurb. If it goes tits up, then complete new everything.
S

 

[LadyInBed]

A piggyback Question
When you buy new, the compressor unit and plate unit all come gassed up and sealed, connecting them together completes the circuit.
Q: If you seperate these joints, do they self seal or do you loose the gass?

 

[skyflyer]

A piggyback Question
When you buy new, the compressor unit and plate unit all come gassed up and sealed, connecting them together completes the circuit.
Q: If you seperate these joints, do they self seal or do you loose the gass?

Looking at the downloadable instruction manual there might be a tiny leak of a drop or two but they are self seal. New units seem o come recharged in each part and then you connect with the quick couplers and there is no need for professional charging of the system.

Obviously (well I hopped it was obvious) I realise that if I try and 'repair' the condenser/compressor (and remember its not broken as such, just the base plate has rotted away)there are 3 possible outcomes:
1) DE-couple, self seal works, no fluid lost, repair to mountings made as planned
2)De-couple, self seal doesn't work, (or I wrongly identified it as self seal but they aren't!) gas is lost, repair made
3) Either of the above and during attempted repair it all goes to a ball of "rusty' chalk - e.g. moving everything around is the final straw

So if I do this I am quite willing (if I have to) to buy a new compressor/condensor unit. What I am less keen to do is by and install anew evaporator plate in the fridge and run all the tubing as that will be a MAJOR dismantling job. Hence my enquiry about whether its OK to put "new wine in old bottles" as it were, i.e. just replace one 'half' of the system. If this wasn't in the manufacturers mind, why would they bother witch quick link self seal couplings? But a local 'expert' started mumbling about contamination when you take the two parts apart.

 

[superheat6k]

Looking at the downloadable instruction manual there might be a tiny leak of a drop or two but they are self seal. New units seem o come recharged in each part and then you connect with the quick couplers and there is no need for professional charging of the system.

Obviously (well I hopped it was obvious) I realise that if I try and 'repair' the condenser/compressor (and remember its not broken as such, just the base plate has rotted away)there are 3 possible outcomes:
1) DE-couple, self seal works, no fluid lost, repair to mountings made as planned
2)De-couple, self seal doesn't work, (or I wrongly identified it as self seal but they aren't!) gas is lost, repair made
3) Either of the above and during attempted repair it all goes to a ball of "rusty' chalk - e.g. moving everything around is the final straw

So if I do this I am quite willing (if I have to) to buy a new compressor/condensor unit. What I am less keen to do is by and install anew evaporator plate in the fridge and run all the tubing as that will be a MAJOR dismantling job. Hence my enquiry about whether its OK to put "new wine in old bottles" as it were, i.e. just replace one 'half' of the system. If this wasn't in the manufacturers mind, why would they bother witch quick link self seal couplings? But a local 'expert' started mumbling about contamination when you take the two parts apart.

A new condensing unit should work just fine with the original evaporator plate as long as the capacity is about the same. The pipework would go again. Compatibility of the self sealing connectors would be doubtful, even from the same maker.

Do not use temporary snap on access valves. These are only suitable for washing machines or degas of an existing system, and will leak if used as a permanent fixture.

If you are somewhere near Hamble I could (legally) pressure test, evacuate and gas it up for you with R134a. Other comments about good money after bad should be heeded, so if the CU is at all dodgy I would bin it and get a new unit.

 

[ghostlymoron]

If its working and only the base plate corroded, couldn't you just unbolt the whole assembly from the baseplate without uncoupling any thing, fabricate a new baseplate and reassemble. No re-gassing to worry about. Or is this to simple?

 

[ghostlymoron]

If its working and only the base plate corroded, couldn't you just unbolt the whole assembly from the baseplate without uncoupling any thing, fabricate a new baseplate and reassemble. No re-gassing to worry about. Or is this to simple?

 

[skyflyer]

If its working and only the base plate corroded, couldn't you just unbolt the whole assembly from the baseplate without uncoupling any thing, fabricate a new baseplate and reassemble. No re-gassing to worry about. Or is this to simple?

I wish! Its tucked in a corner, underneath the overhandg of the locker edge and overlapped by the adjacent gas locker above it. Pretty unaccessible and of course the bolts that hold each item onto the baseplate need to be accessed from underneath the baseplate to undo them (well-possibly not as they rusted away almost, but certainly to re-do them!) Plus I don't think theres enough length and flexibility in the piping (copper) that joins the condenser to the compressor to move anything much without the risk of bending and kinking the copper pipe!

What I have done for the moment is clean away as much as I can of the rusted baseplate, and then used fibreglass matt and resin to create a lip to hold each component down to the wooden shelf. My main concern is that if i could get it all out and look at it properly I could perhaps identify and treat areas of corrosion that might cause the unit itself to fail. By just 'repairing in situ' it will probably continue to corrode and eventually need replacement.

 

[l'escargot]

Bite the bullet and replace it - if you're keeping the boat you'll get the benefit of it and it is one less job to come up in the future. A new one will probably be more efficient too.

 

[skyflyer]

Bite the bullet and replace it - if you're keeping the boat you'll get the benefit of it and it is one less job to come up in the future. A new one will probably be more efficient too.

No issue with that over the winter - but don't want the major disruption of doing it now mid season. If it was a straight 'disconnect and reconnect new' I wouldn't hesitate, hence my questions about the efficacy of self seal couplings and the need to replace the evaporator plate as well.

My plan now is leave everything undisturbed and get through this season then sort it over winter.