View Full Version : dust in system

neil sailes
21-06-2005, 08:54 PM
Hello all

I have started to come across a problem that I have never seen before, some of the back bar fridges I work on from Turkey will run happily for about two to three weeks, then will show symtems of a blockage.
After reclaiming the refrigerant I place about 100psi of ofn through the system and have clouds of dustcoming out of it this has happened to units with both R134a and R404a in them.
Has anyone ever seen anything similar and did you find a cause.


21-06-2005, 09:05 PM

Had trouble with a R134a some time ago,the cap was restricted when I removed it from the drier there was a furry powdery build up on it.I imagine that was the same thing I replaced the cap line and it was fine.A lot of people say R134a causes caps to block but I really have had no trouble.I,ve seen a lot of the supermarket guys who only have one set of guages,going from a R22 pack to a small R134a integral.I think this causes a lot of problems.

Regards Bernard

21-06-2005, 10:24 PM
the dust is caused by the fracturing of the activated alumina desicant in spun copper bullit driers, If the capillerie tube is pushed too far in when assembled and touches the fine copper gause filter then this dust only has to collect over the top of the cap tube and cause a restriction. The capilerie tube therefor should NOT be pushed too far into the drier. Thorn EMI who manifactured Tricity refrigerators had this problem back in the eighties. Next time one fails, cut the drier in half before removing cap tube, empty desicant and look at the gause filter.

17-05-2006, 08:47 AM
Hello all
i work for one of the largest commercial refrigeration manufacturers in the UK. We had the same problem when we used a new "cost effective" filter drier, few months passed and the drier core turned into powder choking the system and causing expensive warranty claims. we stopped using these type of filters with immediate effect and have never had the problem since.


17-05-2006, 09:47 AM
I have similar experience with drier filters and just reclaimed a couple of those and cut in two.
Really the drier is fracturing and releasing dust and particles, but the main cause for this is a progressive clogging by humidity and dirt (talking about split DX systems installed and commissioned by third parties). The increase in pressure drop, increases the speed over the non-clogged areas of the filter, until the speed is so high to cause
1) expansion of the liquid after the filter (pipe frozen)
2) fracture of the core

The same filters installed by ourselves in sealed circuits do not cause any problem.

17-05-2006, 02:56 PM
NoNickName and R600Bang (is the Bang after releasing R600 :) ) , may I ask, what brand are the faulty driers.
PErhaps we install those and I an better learn from your experience before having warranty claims.

17-05-2006, 03:26 PM
NoNickName and R600Bang (is the Bang after releasing R600 :) ) , may I ask, what brand are the faulty driers.
PErhaps we install those and I an better learn from your experience before having warranty claims.

GMC is the one we use most. We also used Castel, which seems to be more tolerant. Tolerance in a filter is something that I don't like.

17-05-2006, 06:23 PM
i will look at the lab reports tomorrow and give you the manufacturer name, i know that the company i work for took the drier manufacturer to court and claimed damages. we are now using KMP filters on the larger equipment and Texan and the smaller equipment, so far with no problems!!!!

18-05-2006, 08:23 AM
I came across this a few years ago with a company I worked with.

Most of the units we worked with were under 3HP.

A new guy who started working there installed a lot of his driers on vertical rises with the flow of liquid upwards through them.

A lot of his driers began to break down within weeks of being installed.

Once they were installed correctly with the flow downwards through them the same make of drier were fine, didn't break down any more.

I insist that all our engineers do this with all driers now and we never get problems from them.