PDA

View Full Version : non-condensable test from the low pressure side



pvl
18-05-2018, 05:45 PM
Hi
Old vehicles have air conditioning at R12 and some of these cars have only one low-pressure service port. If it is necessary to perform a test of non-condensables, can we do it from the LP side ?

Rob White
18-05-2018, 08:05 PM
.

No

R12 is banned so you need to remove the remaining charge
and then if you test it with nitrogen (OFN) vac it out you can
put another replacement refrigerant in.

Rob

.

pvl
18-05-2018, 08:59 PM
I know that. Of course these are running with new refrigerant. the subject is not about gas but the fact that there is only one low-pressure port. It does not answer my question.

cadwaladr
18-05-2018, 10:35 PM
Ok fit one?

Rob White
19-05-2018, 05:32 PM
.

A system as small as a car, van, truck or other AC is so small the amount of refrigerant is measured in grammes and if non-condensables are in, how did they get in?

When was purging a system acceptable? Not since the 80's or 90's.

Vac the system from the low side and weigh in new, purging is bad practice.

Rob

.

charlie patt
19-05-2018, 09:47 PM
I've never known the older stuff not to have h p and l.p. they tend to have several various ports and even sight glass as these had standard threads some had a smaller thread on h p like most of the jap and French stuff
to be fair I don't really understand the question to test for non condensables on a Vechicle is normally not required
What Vechicle is it please

pvl
20-05-2018, 10:26 AM
A few cars from Renault have only one low-pressure service port. Even those who have R134a

charlie patt
20-05-2018, 08:37 PM
Yes but not pre 1993
Only the later ones have a hp port on the l p line ie megane or scenic
some Volvo has 1 port as well
every Renault pre 93 car ie on 12 has two ports plus like the 18 and the 9 even the fuego has two just a bitch to find what Renault is it

pvl
24-05-2018, 05:26 PM
today I plugged the manifold on the lp. it reads 88 psi 82 ° F. It's the same outside temperature. Can I deduce there are no non-condendables ?

cadwaladr
24-05-2018, 05:49 PM
Is it r12 thats in the system,i will look at my old comparitor charts if i can find them

pvl
24-05-2018, 06:35 PM
No R134a. sorry for the mistake.

cadwaladr
24-05-2018, 10:08 PM
Recover the charge,vac the system and rechsrge with virgin refrigerant thats my advice

charlie patt
24-05-2018, 10:25 PM
No that’s fine if anything pressure is a little low

cadwaladr
25-05-2018, 02:33 AM
I really do not know what the symtoms of thd original post were,was there a problem with the system?

pvl
25-05-2018, 08:31 AM
the owner tells me there were non-condensables

Rob White
25-05-2018, 09:11 AM
.

Where did the non condensable come from?
It doesn't just appear! It was either sucked in through
a leak or it was put in by a person

If a leak that needs dealing with correctly.

Rob

.

pvl
25-05-2018, 11:59 AM
I think he tries to recharge by himself.

Rob White
25-05-2018, 02:36 PM
.

Fair enough :D

If he is a friend or family member then I'd
help him out and do the job properly for him
but if he is a paying customer, just smile advise
him what he needs to do and then stand back.

These jobs can never pay because there is more
work than they are prepared to pay for and the
simple fact that he has attempted to do this himself
shows what value he puts on it.

:)

Rob

.

cadwaladr
26-05-2018, 01:30 AM
Very true Rob,I have been asked many times to quote "gas up"" car a/c by people I warn them that it must have a leak if the gas is gone and make them aware of the cost to find it straightaway many choose to wind the windows down for two weeks of the year lol

charlie patt
26-05-2018, 04:33 PM
Ah yes we had one of these in our workshop
took1.7 kilos out of a 220 Merc up tested fixed leak up test overnight all good vac and gassed it engineer backed it out but when he hit the brakes it sounded like carnage from the boot had a quick look and there was13 disspossable recharge containers !!!

cadwaladr
27-05-2018, 02:06 AM
Car a/c personally could not be bothered with it,ok some make money out of it but i find it to be a pain would rather work on a larger system nickles and dimes

nike123
10-06-2018, 08:46 PM
Hi
Old vehicles have air conditioning at R12 and some of these cars have only one low-pressure service port. If it is necessary to perform a test of non-condensables, can we do it from the LP side ?
Yes you can. Just put car in stabile enviroment to stabilise tempetatures and measure gas presure and ambient temperature. On your manometer saturation temperature must be equal to ambient temperature.

cadwaladr
10-06-2018, 11:31 PM
Just take the charge out,then recharge it with 134a change the oil charge in compressor vac it job done