R134a, or R22 contamination - how to resolve?

[desA]

Have an odd case to hand & I wonder if some wise sage can advise?

Customer brings in a small heat-pump today that has been running since Aug 2011 - apparently 'poorly'. Find out that he has opened the compressor insulation (ripped, in fact) & extracted the compressor nameplate.

It shows: LG Electronics - QJ208PHE / 220-240V - 1115W LRA29 / 1ph 50Hz

It seems that this customer may have been doing a fair bit of research & is convinced that this is a R22 compressor. (The LG series names would tend to bear out the implication). The unit name plate claims R-134a compressor.

Now, the story gets more interesting:
When I got back to the factory, the staff had the unit on test, but I noticed a very slow temp ramp & high-side pressure / low-side pressure discrepancies from normal running conditions, I'd have expected from experience. In my mind, the system looked to have a false refrigerant installed. I then looked at the site glass & noted what looks like thick vaseline in the lower part of the sight-glass - thick bubbles trying to flow back up vertical direction.

Switched the pump off - see a white inner ring inside the sight-glass, with what almost looks like silica gel particles on the inside of the glass. Seems like a refrigerant contamination issue may be at play here. I suspect compressor actually specified at R-134a per manufacturer agreement, R-134a initial charge - customer plays, gets it wrong, then brings machine when stuck.

Not quite sure if this mess is resolvable in terms of potential compressor & system damage if the client has been in fact playing & has inadvertently re-charged with R22. I don't like the look of the oil. What is your advice?

Thanks everyone.

[chemi-cool]

if you see silica gel in the sight glass then it must be silica gel, most probably blocked capilar/txv , maybe compressor valves, in my opinion, cut all pipes and clean it with nitrogen and assemble it back with 134.

[desA]

if you see silica gel in the sight glass then it must be silica gel, most probably blocked capilar/txv , maybe compressor valves, in my opinion, cut all pipes and clean it with nitrogen and assemble it back with 134.

Thanks so much chemi... Now, how on earth does silica gel get into the system in the first place (filter drier collapsing, inside pipes at assembly?)?

[mikeref]

desA, what is the rated cooling capacity of this unit? I would think a mixing of oils, (mineral and synthetic) would create that effect you see in the sight glass. Think you might have to upend compressor and see what comes out and do an acid test. Does the standing gas pressure correspond to figures on the pressure/temperature chart?.. Mike.

[desA]

desA, what is the rated cooling capacity of this unit?

Cooling capacity around 2.2 kW. Compressor is aircon-type rotary.


I would think a mixing of oils, (mineral and synthetic) would create that effect you see in the sight glass.

This was my first impression, I have to say. A ring of white residue remained around the edge of the inside face of the sightglass. Indicator indicated 'dry' refrigerant condition.


Think you might have to upend compressor and see what comes out and do an acid test.

Good point. I'll get this done, as part of the process. It'll give us an idea of what has happened.


Does the standing gas pressure correspond to figures on the pressure/temperature chart?

Another good point. The standing pressure at room temp is within the range of the pressure/temp chart - very different to R22 etc.

What I'm beginning to suspect has happened here is that the machine has been played with - the owner is an 'experimenter' it seems. The thought is that he/someone ripped off the compressor label, researched the compressor model, came to an incorrect conclusion, must have added mineral oil & R22 during his experiments, noticed an issue in terms of sight glass, changed gas type back to R-134a, brings in machine complaining that it does not perform. Something along those lines. :(

[a/c.nick]

bin the LG and sell / install him a new one and tell your customer to leave it alone. are small splits really worth mucking round with if they arnt under warrenty?

[desA]

bin the LG and sell / install him a new one and tell your customer to leave it alone. are small splits really worth mucking round with if they arnt under warrenty?

Fair comment. Thanks 'a/c nick'.

[chemi-cool]

What I'm beginning to suspect has happened here is that the machine has been played with - the owner is an 'experimenter' it seems. The thought is that he/someone ripped off the compressor label, researched the compressor model, came to an incorrect conclusion, must have added mineral oil & R22 during his experiments, noticed an issue in terms of sight glass, changed gas type back to R-134a, brings in machine complaining that it does not perform. Something along those lines.


What I understand from your words is that you should dump the machine or send him to someone else or sell him a new one.
If you will start messing with it it will cost you.

[desA]

Chemi... my thoughts as well. I don't want to get too deeply into this.

I'll put up a few pictures of some of the damage. A rather amazing thing that people treat their own machines with such disrespect.

[desA]

http://i41.tinypic.com/2n0pv9c.jpg

Sight glass

http://i41.tinypic.com/2airm9j.jpg

Compressor insulation damage

http://i42.tinypic.com/j6lpwx.jpg

Evap 'sealant'. What gives? Also the fins look pretty pristine for a unit that has been in operation since Aug 2011. :)

[desA]

Out of interest, trying to speculate on the root cause of the sight-glass gunk - a few ideas:

Owner tears into heat-pump with a view to trying to build an equivalent (in China); plays around with system & loses gas charge; tears open compressor insulation blanket to find out more info; finds 'R22' compressor info; perhaps has also lost some oil along the way; charges R22 & some mineral oil; runs the unit; doesn't perform; realises in trouble; dumps R22 fills to R-134a charge on heat-pump nameplate; drops off unit.

Mix of mineral oil/POE incorrect, leading to oil sludging.

Is this white 'vaseline' typical of such contamination?
Can this be flushed out successfully - if so, with what?
Change of filter drier?

What amazes me is that when the 'owner' is questioned, he defends his gross tampering with the machine but swears on anything & everything (including the dog's fleas) that no-one touched the refrigerant.

[simon@parker]

not being disrespectful to all the engineers out there but he would make a good fridge man he is full of it :) it being the word would walk away from this as you will end up trying loads of things and am gonna guess he wont pay up saying it still wont work and he fixed it himself in the end good luck with it if you do try let us all know the out come :)

[desA]

Thanks Simon... LOL :D

Based on a day to think things over, combined with much of the applied wisdom on this forum, I plan to write up a brief technical report on the matter (pictures included) & notify the 'owner' to collect his machine.

Based on the recent issues with explosions regarding pirate refrigerants (lots of it in Africa), the remaining unknown refrigerant has been removed to a safe place, & machine made safe after OFN purging, with safety holding charge of OFN installed. Our team considered that it would have been grossly irresponsible to return the machine in any other form.

He can then carry on playing to his heart's content. He's obviously excellent at this & our team should not rain on his parade.

Thanks again everyone for your thoughts. Sometimes it helps to think around such matters.

[Gary]

Is the system self-contained or is it a split system? It is unlikely that the system would be contaminated at the factory if it's self-contained, but could have been contaminated by the people who connected it up if it's a split.

Difficult to tell what the contaminant could be without analyzing it. Could be just about anything. POE oil is highly detergent and will scrub the inside of the system, depositing the resultant gunk in the drier or metering device.

I would not consider it unusual at all for them to use an R22 compressor (charged with POE oil) in an R134a system. It could very well be part of their strategy, giving them a stronger motor.

[desA]

Thanks Gary.

The unit received is a fully self-contained system, not a split. It would have contained original factory R-134a/POE at shipping - as reflected on the unit nameplate. The unit was also (apparently) still under warranty. There would be no valid reason for the 'client' to have experimented, or worked on the machine, without reference to the warranty provider.

The warranty provider had a policy in place to swap out an operating unit, with a spare unit within 24 hours, in the event of in-field performance issues, such that the 'client' would have always had hot water. The client had never contacted the warranty provider, it seems. There appeared to be no valid cause for the 'client' to butcher the machine, or even open its covers - let alone ripping compressor insulation etc.

I will be advising our team to walk away from this machine.


I would not consider it unusual at all for them to use an R22 compressor (charged with POE oil) in an R134a system. It could very well be part of their strategy, giving them a stronger motor.

Very valid point.