Xantia air con not working...

Post your Cit/Peu/Ren air conditioning queries or advice.

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Kowalski
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Xantia air con not working...

Post by Kowalski » 03 Apr 2005, 20:05

The first day of warm weather comes along and my Xantia's air conditioning doesn't seem to be working, it worked when the weather had been colder...
When I press the button on the dash, the cooling fans (external) start up but the engine revs don't go up as they should. The air inside the car doesn't get any cooler either even set to full cold with the fan on full (recirc or external air).
Could this possibly be a temperature sensor problem or a pressure switch problem or is it more likely a short of gas problem?
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Xantia air con not working...

Post by ghostrider » 03 Apr 2005, 23:58

Kowalski, if you put the suspension on high and look in through the drivers side wheel arch, you will be able to see the pulley on the end of the compressor, there is a clutch unit on it so if the centre is stationary the compressor is not running, check the wiring to the clutch (connector at Opp end of compressor), as far as I know the clutch is controlled by the temp control and the pressure switch. I got info from the peugeotlogic.com site. From the diagram I have you can bypass the pressure switch by disconnecting the wiring connector and connecting the two terminals together, at this point the compressor should run I think if it does it's either the pressure switch or insufficient gas. I have a nasty feeling that you can't replace the pressure sw with out depressurising the system so I guess you are stuck at that point. If the compressor doesn't run it could be either the compressor or a faulty A/C control unit, If Jon sees your post, I'm sure he'll have more detailed info
Pete
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Last edited by ghostrider on 22 Feb 2011, 07:00, edited 1 time in total.
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Post by Richard Gallagher » 04 Apr 2005, 00:12

If you haven't used the aircon for some time then the seals may well have dried out allowing the gas to escape. If thats the case then find £100 and get it refilled, ouch!
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Post by Kowalski » 04 Apr 2005, 02:12

Its been a while since I last used the aircon, 2 months maybe since it was last run.
I've disconnected the pressure switch on the top of the driver, it is in fact 2 switches (4 wires) and has markings on it for 3 different pressures hi, med and lo. If I bridge 2 of the contacts (the thicker pair of wires) the air con clutch makes noise and the engine revs drop (and 3 amps flow through my meter). If I bridge the other contacts it makes the cooling fans run flat out. Both switches on the pressure switch are in fact open.
Does the system have any temperature switches on it anywhere or is this the only switch on the system?
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Post by alan s » 04 Apr 2005, 02:37

That is a HP/LP switch.
It's there so that if the pressure gets too high, the fans go into mega fast mode to cool the condensor more rapidly and thereby reduce the pressure. It is there to prevent damage to the compressor or to prevent the high pressure hoses from bursting under normal useage (something often heard in car parks in the tropics when husbands sit in cars with air/con on while wife is in shopping. (ie) big bang followed by a cloud of oil/gas vapour and husband suitting there with dumbstruck look on the face)
The other part of the switch is the LP safety cut out. This is there to prevent the system sucking in air following the loss of gas or if there is a blockage. It also prevents the compressor going into vacuum on the suction side which can in turn also cause the contents of the sump being pumped into the system and cause cooling problems.
Either way, do not under any circumstances run the system for more than a few seconds with either bridged out.
I'll do a post in the next few days regarding checking the system for leaks, checking conversion to the newer gasses and where and how to find leaks.
However in this case I'd say you are up for a regas but be sure to check and rectify leaks before it goes in for a regas as it would appear that a lot of your guys over there leave a lot to be desired when it comes to fixing the leak before they recharge. (A more than fair number out here are no better either from what I've seen particularly on French cars.)
Alan S
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Post by JohnD » 04 Apr 2005, 23:13

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Kowalski</i>
Could this possibly be a temperature sensor problem or a pressure switch problem or is it more likely a short of gas problem?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
My aircon suddenly stopped working in January. It wouldn't clear the steam. I got the gas checked. After it was refilled it worked fine. Cost me £60 and the bloke came to do it at home. If you are situated south of London, I can recomend him.
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Post by Kowalski » 07 Apr 2005, 04:14

I'm not situated south of London, I'm north of London, about as far north as you can go without hitting Scotland.
My Dad has some experience of refridgeration systems (having maintained 3 ice rinks and a cold store) so it'll get sorted. All I need is a manifold gauge set and some R134a....
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Post by tomsheppard » 07 Apr 2005, 14:11

Good luck Kowalski. I would go with what Alan has said about the pressure switch. Just bridge it for long enough to find out if the clutch comes in. This can be done with the engine off, which avoids pulling the oil out of the compressor which you really do not want to do. If the clutch works in normal operation anyway, then have the system leak tested before regassing, in case you have had a stone pierce the condenser. I left my BX in an open car park for two winter months, and it worked just fine when restarted, but it is a fairly new system. Alan gave me a lot of advice on this forum between April and July last year. You may find it worthwhile to try digging it out.
It would be useful
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Post by glenndaleuk » 08 Apr 2005, 00:26

Don`t know if this is helpful but I did see a do it yourself gas refil kit in halfords, if my memory serves me right it was either 29.99 or 39.99.
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Post by Kowalski » 04 May 2005, 04:41

Progress.
I got myself a manifold gauge set and some automotive quick couplers. Connecting them up reveals that there is very little gas in the system, its reading about 4 pounds of pressure. Turning the air con on briefly by bridging the switch reveals that the compressor is OK and produces a pressure difference, taking the low side down to vacuum.
Since the system isn't completely depressurised, I'm hoping I can get away with sticking some gas into it. I won't really be able to tell how bad the leak (if it has one) until I do that, I could't see any obvious signs of a leak, like greasy residue on any of the pipes, although the compressor was covered in used engine oil because its underneath the oil filter and gets dribbled on come oil change time.
Next step, locate a bottle of 134a...
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Post by alan s » 04 May 2005, 05:19

Just remember that if there is any kind of leak on the LP side, the fact it runs into vacuum tells you one thing; it's sucking air in if the leak is on the suction side, particularly on the evaporator return.
Air in the system can create a whole new set of problems. Look closer for the leak because if it was down to 4psi you can rest assured it's a reasonable large one and I would suggest that as it seems to have dropped whilst not in service indicates it's on the suction side; losing it when operating is more the sign of a high side leak.
Alan S
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Kowalski
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Post by Kowalski » 04 May 2005, 15:08

I don't think the pressure is indicative of which side the leak is on, since they're both connected, immediately after turning the compressor off the pressue on both sides equalises (via the TX valve). If you put a hole into the system at any point all of the gas would leak away eventually.
If there is a leak to be found, I think finding it is going to involve a great deal of dismantling.
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Post by alan s » 04 May 2005, 17:35

I made that observation based on several years of experience.
If it leaks when off in 99% of the time it's what is known in the trade as a "low side leak" and a usually a high side leak comes about when the system is running. The point is that the system equalises when it is switched off and low pressure sides get as much pressure in them as the high pressure sides and this pressure is controlled by temperature and load back through the system. High pressure is reduced and low pressure increased.
I'm well aware of the amount of trouble it is to find a leak I was trying to save you a lot of time, but....carry on.[:D][:D]
Alan S
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Post by Kowalski » 04 May 2005, 18:28

I do appreciate the effort, but.... both pipes are routed as a pair where I can see them, so if I have to take anything apart to see where they go, they both go there together.
Worst case is that the leak is on or around the evapourator, that means dash out. If its on the condensor, that <i>just</i> means front bumper has to come off which is far easier to do.
Why in particular does the low side leak? Is it because the high side is engineered to tolerate higher pressures and is just more durable?
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Post by alan s » 05 May 2005, 04:04

You got it the first time; the low side is less leak tolerant based on its design.
Everything on the high pressure side is in a much smaller sized tubing and usually you'll find that say a 1/2" fitting that usually is holding say 5 - 10 psi will become more vulnerable at say 80 - 100psi than a 1/4" fitting that is running at around 150 - 200psi when operating. This of course then drops to 80 - 100 or on cold days even less. There is also the facts that the HP side is the one running hot (expanding) and the LP cold (contracting but then expanding when the ambient temperature or sun heats it) and the LP side needs to carry increasing pressures when off whilst the HP carries decreasing pressures. The surface area or circumference of the LP side is larger therefore allowing for a greater chance of leakage and flexing.
I don't want to sound like a "Job's comforter" and I'm not trying to sound like a crystal ball reader, but there's a strong chance that the leak will turn out to be either at or on the T/X valve.
The access to this may not be as bad as you think as a T/X valve is usually considered to be a 'serviceable item' and as such is usually made accessable even by the French.
On a BX it's a case of removing the glovebox (6 or 8 screws) and removing 2 hex headed PK screws to gain viewable and physical access to it (just changed one on my 16V) and I understand on an XM they were the same as the old CX in that they are on the outside of the firewall under the bonnet.
If it has the BX style of T/X there will be 4 pipes screwd into it as it's an internally balanced type whereas the older CX style have two pipes and a capilliary attached to the coil with a stainless strip. If it's the BX style which it could easily be, you need to use two spanners; one to hold a fitting whilst the second removes the other fittings. When it gets down to only one fitting to be removed, you need something to hold the body of the T/X so as to not cause damage to the actual coil.
"O" rings are of the green neoprene types; and must be replaced once disturbed. Black rings are of the type used in R12 systems and must be replaced throughout as they will rot out. My guess is that there will be a better than a 50% chance the leak will turn out to be on the fitting to the intake to the T/X valve. This is a most common place for these systems to leak. Another is a crack in the bellows on top of the T/X.
If a leak is found and the system has to be opened to rectify it, this isn't as big a deal as they may try to tell you; I won't go into it now, but I think I did tell Tom a few tricks to this as regards what is needed and how to do it and it worked OK for him.
If you can't find it, I'll re-post it for you.
Alan S[;)]
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