Plugged Capillary R134A Connection

[CHilly1]

In the past three weeks I have had 5 beer coolers (R134A)three under counter freezers (R404 134A Containing Blend) 1 2 Door Up right Freeer (404A) four chest freezers, this is about average over the last three years. The capillaries are plugged with a Grey ash like substance that has the texture of duct seal/creasote and is only in systems containing R134A, the compressors were not burned and the oil still maintained its lubricity. One system had an inoperable compressor (RLA was 29 and and compressor amps was 28A peak during start then O/L opened) The systems have an oder like fish oil more pronounced in the 404 systems, I opened one running compressor and noticed some winding abnormalities, compressor was an AEA4440YXA with ser number inticating OCT 06 as date of manafacture.
The big question... Is there a Problem with R134A and capillaary systems? Is this problem related to the original problem with R134A that percluded its use as a refrigerant in the 1950's?
My solution to this problem has been the use of R401A in the bottle coolers and other high Temp systems and the use of R507 in Freezers with capillary systems.
Has anyone else seen this issue??

[Dilip sahasrabu]

I think that R-134a and capillary does not pose this problem, just wanted to confirm whether the system was originally charged with R-134a or retrofitted without cleaning, as far as my knowledge AE series compressors are for R-22.

[jimmylcoleman]

In the past three weeks I have had 5 beer coolers (R134A)three under counter freezers (R404 134A Containing Blend) 1 2 Door Up right Freeer (404A) four chest freezers, this is about average over the last three years. The capillaries are plugged with a Grey ash like substance that has the texture of duct seal/creasote and is only in systems containing R134A, the compressors were not burned and the oil still maintained its lubricity. One system had an inoperable compressor (RLA was 29 and and compressor amps was 28A peak during start then O/L opened) The systems have an oder like fish oil more pronounced in the 404 systems, I opened one running compressor and noticed some winding abnormalities, compressor was an AEA4440YXA with ser number inticating OCT 06 as date of manafacture.
The big question... Is there a Problem with R134A and capillaary systems? Is this problem related to the original problem with R134A that percluded its use as a refrigerant in the 1950's?
My solution to this problem has been the use of R401A in the bottle coolers and other high Temp systems and the use of R507 in Freezers with capillary systems.
Has anyone else seen this issue??
This article really caught my eye. I recently installed a straight from the manufactureer a brand new Upright reach-in freezer. The new unit stopping freezing within in 24 hours. Presure checks revealed a vaccum on the suction side. This brand new unit is also a R-134A Unit. Know what a total pain it is removing an evaporator from a brand new reach in....only to find the capulary blocked? I think the factory shoved the cap tube into the evap or crimped it intervertantly....I will never know. However, I will be alert for this condition in the future with every R-134A system I service.

[kooler]

I've seen this condition with 134 and 404, even plugged TXVs on 4 occasions... All I can recommend is replace filter driers regularly.. If it's a refrig rack, it may be necessary to replace driers bi-annually... Not something your customers want to hear but it's the nature of the beast.. These systems are highly sensitive and create this sticky 'stuff'... Good luck.. kooler

[Refcol]

In the past three weeks I have had 5 beer coolers (R134A)three under counter freezers (R404 134A Containing Blend) 1 2 Door Up right Freeer (404A) four chest freezers, this is about average over the last three years. The capillaries are plugged with a Grey ash like substance that has the texture of duct seal/creasote and is only in systems containing R134A, the compressors were not burned and the oil still maintained its lubricity. One system had an inoperable compressor (RLA was 29 and and compressor amps was 28A peak during start then O/L opened) The systems have an oder like fish oil more pronounced in the 404 systems, I opened one running compressor and noticed some winding abnormalities, compressor was an AEA4440YXA with ser number inticating OCT 06 as date of manafacture.
The big question... Is there a Problem with R134A and capillaary systems? Is this problem related to the original problem with R134A that percluded its use as a refrigerant in the 1950's?
My solution to this problem has been the use of R401A in the bottle coolers and other high Temp systems and the use of R507 in Freezers with capillary systems.
Has anyone else seen this issue??
There certainly is a problem on capillary's smaller than 0.032", I was involved with Quest refrigeration some years ago repairing on the production line, Quest and Candy were the first two company's to produce units with R134a in the UK, and also the first to have the problems of capillary blocking with this grey/white compound. Between us we had components from several units analyzed by a university, the results were unclear, However my own investigations found that R134a when overheated was stripping the dessicant beads in the drier and firstly depositng them approximately 12" from the injection point of the evaporator. This is where the supaheated refrigerant cools the liquid in the capillary to a point where the particale's would stick to the walls and slowly cause further restriction. But unfortunately just changing the evap and drier does not always cure the problem as some particale's remain suspended in the Compressor oil. shortly after finding the problem we recieved info from two compressor manufacturers telling us not to use capillary's less than 0.032". engineers accross the world have seen this on larger capillary's i am sure, I know I have all be it rarer! But always from overheating. HAVE'NT SEEN THIS PROBLEM FROM CORE DRIERS?

[proby]

If you have a R-134a sys with cap tubes and it gets hot from a dirty condenser or something else. The oil breaks down and the tubes get cloged. the only thing you can do is blow out the sys with nitrogen, replace the cap tubes, flush the compressors with fresh oil as many times as it takes. Then blow out the sys again with out the compressor hooked up. also change the dryer. this works well. have seen alot of 134a sys with the same problem this has been working for the last 2yrs but you must flush the compressor, and blow the the sys free clear iwth alot of nitrogen other wise you could be back there in gain in days.

[Gary]

As I understand it, the problem is POE oil. POE is highly detergent. The good news is that the inside of the system is sparkling clean. That bad news is that all of the gunk it collects is deposited at the metering device.

[FEISTY]

I can relate to the frustration we as service techs are going thru with R134 units and cap tubes. The ***** is highly sensitive to heat and moisture. If the condenser coil is not kept clean, the oil [ POE ] turns to something similiar to chocolate syrup. This plugs up the copper spun..factory installed.. filter dryers and , if unlucky , gets into the cap tube and that's that !! I ususally look at the ID labels on the compressor for a quick but accurate tattletale of how hot the system has been running. You should find the " white " label is turning brown due the excessive heat cooking the adhesive that holds the label to the body. You will find a temp difference in the inlet to outlet sides of the filter, also a tattletale of a blocked dryer. I have found that a product called Thawzone, which is intended to help keep moisture out of the lines when used in a low temp [ freezer ] situation will often act as a line cleaner if the problem of slow flowing cap tubes is caught early. Saves you from having to pull new cap tube assm. But be aware that the cleaning effect usually compounds a plugged copper spun filter. Best bet is to try Thawzone to see if cap tube starts to clearand pressures return. Then evaluate situation and , if possible, chance copper spun filter with a solid core designed filter dryer like Sporlan or Alco . The larger capacity and improved filtration design will help avoid multiple filter changes. The first line of defense always has been and always will be " KEEP THE CONDENSER COIL CLEAN EVERY 30 DAYS ". The customer needs to understand that they can reduce nuisance bills by being responsible for regular cleaning of equipment. Sorry to be longwinded but there wasn't a quick way to explain what I meant to say. Good luck !!

[runningonavac]

See this all the time! I have been told that 134a strips the shilak (spelling?) off the motor windings and deposits it up the capillary. I generally find that only the first 2 ft or so of the capillary is blocked, so replacing the entire capillary is not always necessary. A good flush with Nitrogen, new drier and a good vacuum sorts it out and rarely does the problem re-occur. I'm not yet convinced its the oil or the oil alone causing it. All I know is it's a nightmare. :(

[WINJA]

we had a big problem with custom made cabinets for heineken and steinlager beer where the driers were breaking down and coating the cap tube and evap in grey/white powder eventually blocking them we had to change every cap tube and evap and fitted sporlan solid core driers .
we have also had this problem recently on 404 a systems fitted with blue emerson driers on big condensing units , first the sight glass gets coated then sometimes the tx valve strainer will block