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airconadam
23-05-2007, 09:51 PM
hi fellas iam currently changing a compressor on a york chiller (r22) 15kg. Now when i got to the unit there was oil everywere, obviously a leak i have now found the leak and repaird, but the compressor was down to earth and had blown the fuses so i reclaimed the refrigerant what was left and sure enough i only got 4 kg out. Now the gas really stunk as if it was burnt and ihave never come across this myself before but always been told about it etc now iam not sure wether to put a burn out drier in and if so what does this do exactly, also the postion in the system. is the burnt out not the same as a normal filter drier?? it also has a strainer on it and wondering if to change that aswel which i think i should just let me know thanks alot fellas any help and detail much appreciated thanks adam

marc5180
23-05-2007, 10:02 PM
And now take a deep breath:D

marc5180
23-05-2007, 10:14 PM
If the gas is burnt then id imagine that there must be some non condensables (air, moisture etc) in the system. If thats the case then a burn out drier MUST be fitted. Im not sure but once the drier has been fitted then the system must be allowed to run for about 12 hours When the oil has passed the required test for acid,the burn out drier should be removed and a complete system oil change should be undertaken. Make sure you use a Flared drier so it is easy to change... Not too sure about wether the strainer would need changing but id imagine that it would...correct me if im wrong..

Lowrider
23-05-2007, 10:17 PM
A burnout filter/drier will bond the polution in the refrigirant and oil better than a normal filter/drier.

The filter/drier is always placed in the liquid line, preferbly between two valves or a valve and a solenoid valve to ease changing the cores.

After charging the system let is run, with the burnout filter/drier in it, for at least four hours continues at full load and do an acid test. If it's acid, change oil and burnout filter drier. Let it run again and after a few hours do an acid test. Keep changing the oil and burnout filter driers until all oil is acid free!

My advice is to charge the system with fresh refrigirant and not use the old one and adding new ref to it!

airconadam
23-05-2007, 10:20 PM
thanks alot guys will defo use new ref,should be fun now altering the pipework thanks adam

The Viking
23-05-2007, 10:24 PM
You need 2 things:

1. Acid removal drier in the liquid line
(most liquid line driers does remove acids, just go for the one that has the "best" rating)
2. Burn out drier in the suction line.

As both driers will require frequent changes (at least to start with) and eventually should be removed/replaced with standard driers, I recommend that you use replaceable core ones together with in-line shut off valves before and after.

As you will need to monitor the oil quality/acid level, I would also try and fit an "oil sample valve", depending on compressor type and internal layout in the chiller, this would either go straight in to the crankcase or in to an oil return line. Should this not be possible you can T in to the suction line and put a valve below the suction line (just a small one fitted straight to the T), this will collect enough oil for an oil sample during normal working conditions.

But remember, the only way to get a long, healthy life from your new compressor is to monitor the acid and replace the B/O driers accordingly until all acid traces are removed.

airconadam
23-05-2007, 10:37 PM
i totaly understand thanks alot, what a ball ache :mad: everydays a school day tho :D thanks alot

adam

Brian_UK
23-05-2007, 10:39 PM
Go along with the above and you should be fine.

I thought that most Yorks had a removable core filter already built in but I suppose it depends on the model.

While you're at it you might as well replace the TEV; there will be a fair amount of crud inside it now and the cost of replacing it while the system is down will be less than doing it later.

Also, depending on unit size/model, you will need to replace the compressor starter kit, contactors, timers etc.

goodguy
24-05-2007, 12:39 AM
Compressors don't usually go to ground for no reason. Usually from a unit running to hot, a flooded start(check base heater)or as Brian said, a bad contactor or start component. I am unfamiliar with this equipment, but if it is a hermetic compressor see how much oil is left in the old compressor, if there isn't any, well there is your problem.

Paul@paulrobert
24-05-2007, 08:48 PM
A burn out drier as far as I was taught goes in the suction line just before the compressor to collect any crap that remains in the system if you put it in the liquid line you will have to drag all of the crap/acid through the compressor and have the acid eat your windings before it reaches the burn out drier. Good luck with the new comp.

frank
24-05-2007, 09:19 PM
Have a read of what the manufacturer has to say about it. Page 5 refers to a burn out situation.

http://www.sporlan.com/40-10.pdf

airconadam
24-05-2007, 09:28 PM
hey again fellas ther was no oil in the compressor:eek: the leak was on the discharge going into the condensor were it has been leaking into a fine spray by the way the oil was everywere,could that be the reason for no oil??? i thought aswel paul that the burn out would go on the suction for the reason as you say. I done a acidic test today on the oil and it came back fine thanks alot again to all, anymore views more than welcome:D

adam

airconadam
24-05-2007, 09:33 PM
sorry again but wot makes the oil acidic is it moisture or the fact that the compressor has burnt out?:confused: and if the sample has come back fine is it worth putting a burn out drier in still? ialso dismantled the strainer and that had a little bit of crap as in copper bits:eek: thanks again

adam

The Viking
24-05-2007, 10:33 PM
So, there were no oil in the compressor but you managed to carry out an acid test?:confused:

Never mind, the best test currently on the market has already identified the situation as a burnout (an experienced engineer's nose).

If the new compressor fails in the near future, can you/the company you work for charge the customer for a new one?
Thought not.
It really isn't worth taking any short-cuts.
Follow the advice above, most of it is sound. Let the compressor run for a day, take an oil sample and change the driers. If this oil sample is clear then let it run for 2 days before repeating the procedure. If this test also is clear then just give her weekly oil tests for 2-3 weeks and after that you should be safe'ish. (Remember, you now also has to filter out the metal filings left behind by the old compressor)

Going back to the "no oil" situation, it is unlikely that all or even most oil has gone out through the leak. The more likely scenario is that as the system lost charge the compressor kept running but with insufficient charge to force the oil back to the compressor this now poses another risk for your new compressor.
If it remains in the system then you will get it back to the compressor and it might cause a "hydraulic lock" (i.e.smash the head of the new compressor, just don't ask me how I know this) as you now got twice the oil charge in the compressor.
To prevent this, try and section off the system as far as possible (cut the pipes in and out of the condenser/evaporator) and blast each section through with OFN.

Why the oil become acidic?
- I haven't got a clue, over heated windings and so on but I'm sure someone will be along and tell us shortly.

Final thing to remember when you do the recommissioning, check the LP-switch
:cool:

Brian_UK
24-05-2007, 11:08 PM
Sorry again but what makes the oil acidic is it moisture or the fact that the compressor has burnt out?




The moisture comes first and starts the destruction process.




Sporlan





Excessive moisture in refrigerant systems can cause unwanted chemistries such as hydrolysis of lubricants and other materials, corrosion of metals, copper plating, ice formation at the meeting device and a chemical change in the motor insulation of a hermetic compressor.

airconadam
24-05-2007, 11:15 PM
thank you viking idid get some oil out of the compressor but only a couple of hundred ml, but like you say it has prob gone around the system. I have already blew ofn round the system in short bursts but never really got much out but iknow what your saying with the charge of the oil to much wont be good:eek: thanks alot tho all the help appreciated thanks

adam:D

Lowrider
24-05-2007, 11:23 PM
if the oil is in de condensor, the only way to get it out is by drilling holes in the bottom of the headers!

airconadam
24-05-2007, 11:27 PM
thats not good:( there isnt that much pipework at all the main area is the condensor,think iwil have to change the oil a few times along with the burn out drier thanks alot

adam

al
25-05-2007, 12:01 AM
Adam

if it's one of the Serveso/ycal models with bristol compressors then these were fairly bad for discharge gas leaks, you 've probably dumped most of the oil out through the leak.......make sure you change the contactor and motor protection module!!

al

slingblade
25-05-2007, 09:55 AM
Morning Gents,
I feel everyone is being a little extreme here. Acid burnt systems are caused by moisture reacting with oil and in turn attacking the motor windings. as stated before this unit was very short of gas and as a result the huge superheats around the system have burnt the gas (pungent nasty smell) and the pot has gone D.T.E due to running hot. Given that the total charge is 15kg i estimate about 50kw ish system duty and would not bother with suction driers as i dont think it is warranted. fit a liquid burn out drier if you see fit but i feel a standard will be ok. I have seen hundreds of chillers with "burnt" compressors but a burn out is a different thing, trust me.
I short new comp, new drier, new contactor, fresh gas and walk away. oh, and clean the condensers.;)

airconadam
25-05-2007, 04:17 PM
so many different views well iwil tell what i done and how it runs from next week because,its all piped up and ready to go now just under pressure at the mo then a good vac out thanks alot

adam:D

airconadam
29-05-2007, 08:36 PM
got the system under vac tonight :D so hopefully try and run it up tommorow depending were and if i get called out

adam

airconadam
30-05-2007, 05:38 PM
system all up and running and no problems at all smooth as anything thanks alot guys

adam:D :D :D :D :D

Brian_UK
30-05-2007, 07:49 PM
That's OK Adam, glad to hear all is well so far; so it's doughnuts all round then:D

taz24
30-05-2007, 08:19 PM
system all up and running and no problems at all smooth as anything thanks alot guys

adam:D :D :D :D :D

Hi Adam.

Just bear in mind that if the system now has burn out driers in, they will need replaceing after a short period. Dependant on the type you used they will either need replacement driers or straight connecting tubes that replace them.

All the best taz.

taz24
30-05-2007, 08:24 PM
Adam are you out working on your own.
You sound like a very switched on engineer and the work you are doing sounds very chalenging.
But from the questions you ask it sounds like you get no back up from work?

I welcome your enthusiasm and from what you have described you are doing well and calling the right shots. You are learning by doing and I personaly belive that that is the best way to learn.

Well done mate and enjoy what you do.

All the best taz.

airconadam
30-05-2007, 10:05 PM
thanks alot taz;) ihave recently changed job and not really got all that much back up unlike my old firm, so i have to ring alot of people depending on the job as you know its only easy when you know or been shown but i dont like bodging things and like to know the ins and outs of everything eg, why it did that or why didnt it do that etc etc rather do it correct first time than keep going back. Some questions might be simple to you guys on here but its just when iam out on site and think iwonder why that does that etc but thanks alot

adam:D