xantia ac now us

john alexander · Post by **john alexander** » 23 Feb 2005, 00:42

Hi just noticed my air con doesnt work any more ,had a free check at renault dealer in Skipton last summer,they said it was OK.At that time the compressor cycled on and off in short bursts, I was told this was correct??.I checked it yesterday and the compressor doesnt come on at all now but there are bubbles showing in the sight glass. Where do I start, all the fuses are OK as far as I can see. One other thing fuse 8 and 23, the hand book says they have a dual function but the fuse in my car straddles 8 and 23 Thanks in advance John.

RichG · Post by **RichG** » 23 Feb 2005, 00:47

John,
I had the same problem at the end of last year when we had some snow. The 'guru's' on this forum explained that the air-con is not designed to work at low temperatures as it is liable to ice up. Sure enough when the weather warmed up the air-con started working again. I would wait until the cold snap ends and try it again before you worry too much.
Richard

john alexander · Post by **john alexander** » 23 Feb 2005, 01:04

thanks Rich ,but is the comp meant to cycle

ItDontGo · Post by **ItDontGo** » 23 Feb 2005, 01:22

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by john alexander

thanks Rich ,but is the comp meant to cycle
<hr height="1" noshade id="quote"></blockquote id="quote">
I hope so! It does on all our cars.

RichG · Post by **RichG** » 23 Feb 2005, 01:43

John,
As far as I know mine does not cycle. You can tell when the air-con is on on my car by a slight 'flat spot' at about 2000 rpm which has been discussed before.
Richard

dan.2cv · Post by **dan.2cv** » 23 Feb 2005, 03:19

The compressor won't cut in at all (let alone cut in and out which is indeed normal) if the refrigerant has leaked out. Bubbles in the sight glass indicate that it needs regassing, so that's why your AC isn't working. Take it to the man and have it regassed- problem solved. Usually the reason for leakage is drying of the seals during prolonged non use (the refrigerant acts as a lubricant) which is why your manual reccommends the AC is run for short periods during the winter months. Don't forget as correctly stated above that the AC doesn't work below a certain temperature (I think 5 deg)..

john alexander · Post by **john alexander** » 23 Feb 2005, 03:58

thanks dan but AC is normally left on ,I'll have to wait for warmer weather . one thing though how do you run it for short periods in the winter if it doesnt work in the cold.

alan s · Post by **alan s** » 23 Feb 2005, 05:13

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by john alexander

thanks dan but AC is normally left on ,I'll have to wait for warmer weather . one thing though how do you run it for short periods in the winter if it doesnt work in the cold.
<hr height="1" noshade id="quote"></blockquote id="quote">
This run it once week is a bit overkill in a cold climate.
One of the reasons for the running is that when turned off, the low pressure side comes under back pressure from the system; pressures do what is know as "equalise" which means you end up with the same pressures on the low pressure side as the high. This places strain on the seal as under normal circumstances the seal is only required to hold back say up to 10psi.
In our climates out here, these pressures get ridiculously high on occasions which isn't hard to understand when you think that I got into my Xantia the other day parked on grass and under a shady tree and the thermometer read 43 degrees Celcius!! In that case, my low pressure side was possibly showing around 80 - 100 psi and had I not used the system, just the underbonnet and off the road heat could have driven it up a further 50%. This then turns what may be an extremely small leak into a major event.
Seals used on compressors aren't like a seal on an axle; they don't work just on the lip seal principle, in fact they usually work on two faces mating together under spring pressure and running the compressor simply refaces the mating surfaces and splashes a bit of oil on them.
Bubbles in the sight glass used to be the yardstick to gas charges; again this no longer applies as cars fitted particularly with R134a can often have bubbles at full charge.
I suggested previously (and admitted I didn't know if it would work or not) that perhaps if the heaters were switched on for a while (ie) climate control set to say 25 or over and then the setting dropped back to say 16 - 18 the heated air in the cabin may, just may trigger the compressor. (The reason I haven't tested this is that I live in the tropics so I'll let you use your own imagination as to why I don't know if it works under 5 degrees.)
The compressor works like any other thermostatically controlled fridge or air/con; it will run until it's down to temperature at which point it will switch off. The cycling you refer to may be the thermostat operating or as has been suggested it could also be short of gas. I think you'll have to wait until the weather warms up to find out.
Hope that clarifies matters.
Alan S[;)]