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afak
30-03-2007, 05:31 PM
Hello to every one
A semihermatic 13tons reciprocating compressor with 47 m3/h displacement , RLA 36 amps designed to be used with R22,R502,can we use R404a with it after changing oil with POE oil? . The same company manufactures a semihermatic compressor with the same tons, displacement and RLA used with R404a, are there any special mechanical specifications made compressor acceptable to be used with R404a and not in other cases? I need sligtly detailed discussoin in this matter .Thank You.

Toolman
31-03-2007, 03:22 AM
You have not specified too much here , there is a bit more info required before most people can answer you ( some may guess )
Need to know :
Model number of compressor
Model number of complete condensing unit
You say compressor was designed for 502 or 22 but this depends on the condenser R22 & R502 require different condensers depending on application Low or Medium temp. R404 can directly replace R502 low temp system but TX valve to R404 and POE oil change are required . Dont you have a local wholesaler that will be able to tell you whats OK and whats not . I guess if your not qualified they wont help you ( I hope )

taz24
31-03-2007, 12:51 PM
can we use R404a with it after changing oil with POE oil?


I would say yes.

BUT there are things that need to be taken into acount first.
The comp should be ok and the opperateing pressure will be very similar if set / recommissioned correctly.

My big worry would be with the reaction your new oil-refrigerant mix has on the old seals in the system.
O rings on mag valves, sight glasses, shut off valves and things like that, that require a flexible seal to hold back the pressure may be affected. The new oil may cause the old seals to leak.
If they are not compatible then a complete reseal would be nessesay.
An easy jobinitself just time consuming.

Cheers taz.

lana
31-03-2007, 01:06 PM
Hi there,

Do you have a completed system or just a compressor?
If there is a complete system with mineral oil then the correct procedure must be followed to clean the mineral oil. If we are talking about the compressor then cleaning the oil will be a little bit easier:confused: :eek: .
Also taz24 is completely right. Make sure that the seals are compatible with the oil. The best way is to ask the manufacturer and get their procedure and follow it to the letter.
Good luck
Cheers

afak
31-03-2007, 07:50 PM
1. Dear Toolman:I am going to use a totally new compressor in totally a new appropriate system [new evap.new cond. new every thing] not to say anew R404a TEV .The same successfully designed with R502 in other tens systems we have installed before .
2. Dear taz24:do you mean that I must change the O rings in the liquid and oil sight glasses and other places even if they are made of teflon ? are the seals that used with synthetic oil and HFC *****s some thing different?
3.Dear Lana:my main question to and to other friends :are there any mechanical specification strictly in the compressors made it qualified to be used with R502 in one hand , and not qualified to be used with R404a and POE oil ? say some thing concerns seals ,electrical winding , lubrication , pistons ...........etc.

Toolman
01-04-2007, 12:00 AM
1. Dear Toolman:I am going to use a totally new compressor in totally a new appropriate system [new evap.new cond. new every thing] not to say anew R404a TEV .The same successfully designed with R502 in other tens systems we have installed before

It can be used on R404 then if its a totally new system , if you are doing all new why leave the old TEV ? You say " not to say a new TEV " I'm sure this item wont blow the budget and you will sleep better at night knowing its all matching, you can use the old TEV if you cant get a new R404 one but only if your stuck. Eg: Service Call breakdown situation.

taz24
01-04-2007, 12:24 AM
2. Dear taz24:do you mean that I must change the O rings in the liquid and oil sight glasses and other places even if they are made of teflon ? are the seals that used with synthetic oil and HFC *****s some thing different?
.


If all the equipment is new I can't see any problems at all and you should be fine.
At first I was not sure that you were using new or old equipment. The issue with the seals would only effect the older systems already in use.

taz.

lana
01-04-2007, 12:17 PM
Dear afek,

I did the same thing once but before doing it I asked the manufacturer and got the OK to go. Then there was no problem.
I still say that you can do it as long as the manuf. gives you the OK.
Cheers:)

afak
01-04-2007, 06:45 PM
Thank you toolman ,sure I always mean to use R404a TEV.Thank you taz24. Thank you lana.Thank you all for your advices.Sure I will be so glad for any additional explanation on this matter .

GHAZ
01-04-2007, 10:00 PM
Hello AFAK The difference in semihermetic compressors that are used on HFC gases is they use ester oil for lubrication and the gaskets are either metal or they have special beading around the edges to seal.If they are ordinary fibre gaskets they normally weep and you find oil around the joints

afak
02-04-2007, 04:17 PM
Thank you GHAS for the notices about the effect of ester oil on the fiber gaskets usually used with HCFC *****s compressores and mineral oils.If the compressor was a hermetic compressor [ as I think all the internal gaskets in hermetic compressors are of metal ]and have the same specifications of tons,RLA and displacement mentioned in my first letter in this thread ,does nothing still to be under harmful effect of ester nor R404a ?[some thing like the isolatores of the the motor windings,or discharge and suction valves ...etc.].This hermetic compressor is very successful with R502 .can we use it succsfully with R404a and ester oil?

GHAZ
02-04-2007, 07:36 PM
Hello afak the motor winding or copper coils are coated or insulatated with polyester 200 which has very strong resistance to corrosive chemicals so r404a wont effect it and the service vavles should be o.k. good luck

afak
02-04-2007, 08:58 PM
I have just received an email from the manufacturer of the hermetic compressor .They said there are two differences concern the hermetic compressor designed to be used with HFC *****s :
1.stainless steel suction valves.
2.specific piston ring design.
3.lubricant POE.