Cycle Clog

[Aria]

What is the source of material that can make capillary pipe clog?
is possible from molecularsieve residual?

[Tesla]

Hi Aria
Yes the drier material can clog the capillary. Also I found when a compressor failed on R22 the capillary had to be changed. There was a black coke type of substance. Also any cu filings or foreign material could block the capillary.

[mikeref]

Moisture in system will freeze at capillary outlet to evap. Material from spun copper driers (domestic and light commercial uses) can break down to a powder and flow through strainer and up the capillary. Also heavily contaminated compressor oil can restrict the flow, plus add what Tesla said ^ above. .. Mike

[Tayters]

If the outlet from the drier is at the top then each time the cycle starts the refrigerant pushes the balls up causing rubbing and small bits then flowing around the system.
If the drier outlet is at the bottom the balls have less reason to move as they stay at the end of the drier, where the refrigerant is pushing them anyway, under the force of gravity. Less chance of drier residue clogging the system.

Cheers,
Andy.

[Aria]

if the material color is white, what is the source?
if really from molecularsive, how to countermeasure, may be like reduce amount of molecularsive.....
my outlet drier is at the bottom....and the clog happened often on 15-20 cm from outlet drier...
need your advised...
nice to discuss with you all...

Thank you,

[Aria]

any one can help me? hehe

[mikeref]

White colour is the drier contents broken down to powder. Fit solid core drier, 032 or 052, 1/4" flare or solder. Maybe change capillary while your at it.. Mike.

[Tesla]

I agree with Mike
Also replace capillary and ensure there is no excess vibration or high head pressure.

[Aria]

i know....but i think impossible if we change the capillary...because of the position of capillary is inside of polyurethane...

[Tesla]

You could rip it out, install new capillary then use a can of expanding foam with a little cardboard and tape for the forming or try to flush with an approved solvent like RxxxB?

[Aria]

ok i understand...but, my focus questions is, why the clog can happened....what kind of reaction is...may be like reaction between refrigerant R-134a with POE oil, or the critical temperature of refrigerant & POE oil to form bubble....

[Tradewinds]

Just getting back to the black stuff that can block up capillaries. One of the most common causes is when engineers dont purge OFN (Oxygen free nitrogen) thru the pipework when they are brazing. If OFN isn't used then all the carbon deposits from the brazing process will be left in the pipework and will be stripped away by the corrosive refrigerant. All this carbon then gets pumped around the system and blocks up filter driers, capillary tubes, etc depending on where the repair was made in the system.

Could the fact that it is white and in the liquid line, just be liquid refrigerant that has mixed with the oil but hasn't boilt off. Liquid slugging in a compressor oil sightglass shows white oil.

[Aria]

dear Tradewinds,
you means the welding process is not perfect because the flame is content nitrogen?
my first analysis is like your analyze too...the accumulation of concentrated carbon deposit can form the white material, we can called it graphite...but when we check the material with XRF test, the biggest material content is niobium...
niobium can form by decomposed refrigerant at high temperatures....but i think this is impossible in my system refrigerator, if the temperature achieve until 350 degree,,,
so, based on experience, what should i do first?
until now, i was already enlarge inner diameter, and will be start adding accumulator in suction line...how about your opinion?

[Tradewinds]

Hi Aria,
I mean that many engineers dont use OFN when they are brazing. Brazing should be a 3 gas process. Oxygen & Acetylene from the brazing kit, then we should connect up a seperate bottle of OFN and purge the pipework (gentle breeze only'. By blowing OFN thru the pipework it removes all the dirty air and aids the brazing process.

If you braze without OFN and then cut the pipework open to inspect it, you will find a lot of black soot. The corrosive refrigerant then strips all this off and it blocks up filters, capillaries etc.

Inspection of pipework joints is one of the first thing manufacturers will do when challenging warranty claims about compressor failures.

If you do blow OFN thru the pipework when you are brazing and then cut it open you will see that the inside looks like brand new shiny pipework.

Something else to consider is that if it has had a compressor burnout in the past and a burnout drier/cleanup process wasnt used then the varnish from the old windings can be left in the oil that has circulated around the pipework. A new compressor is installed, vacced out and put into operation, buit this varnish then gets pumped around until it blocks the filters or capilaries.

[Aria]

ow i see...it means difference with oxygen & acetylene...i'll check in our process process...
thank you for your information....i'll check too the composition windings varnish in compressor...
Are you have a private email?

[Aria]

any body know about amid wax?