xantia air con problem?

[AndersDK]

"slightly short of refrigerant"

[fridgedoc]

Hi

And why not slightly short of refrigerant?

The "Water Valve" we Know does not exist, we are GUESSING he means the TEV and as we all know that NEVER CLOSES FULLY!!!!! and yes it could be the heater matrix flap and that's a GUESS and it could be over charged but that would be a GUESS, and the LP could be faulty cutting the a/c off early and that would be a GUESS, but the most common fault is ....... short of refrigerant, but we are still GUESSING, unless I've missed something in my almost 60 years?

I was only trying to be helpful and it is another possibility!.... I GUESS

PS. I know very little about Citroen's that is why I am on this VERY interesting site, I am here because I now have a Citroen and I want to learn...... and EVERY answer I get to my questions IMO will help me further my knowledge, so a BIG thank you to you ALL

[_kid_]

Now that summers here i tried out the air con with a digital reader like the one below


http://cgi.ebay.co.uk/New-Digital-Indoo ... dZViewItem

The outside temp in the shade was 20C

I started the car from cold and conducted a 10-minute test, with the temp sensor on the centre vents, and the fan on full and the car stationery, here are the results in C

1st minute temp- 32
2nd
3rd- 23
4th- 17
5th- 11.5
6th- 9.2
7th- 8.8
8th- 8.5
9th- 8.3
10th- 8.3

With the car moving (now around 15minutes since started) the temp went to below 7c

Then the centre vents were measured with the fan on the next lowest setting, where the lowest it went was 5.2

Using the link below, Ive used the graph which gives an indication as to where the centre temp should be, given the outside temp. From my results it seems to be around the mark, possible a shade too high

http://www.fordgalaxy.org.uk/ford/index ... 227&st=150 the graph is post no 162, 3/4 down the page.


I have to say the air con felt fine, but when the sun was belting down on me, the air con felt rather weak, is this normal? also do the temps look ok or are they too high?

[Clogzz]

The temperatures look very good, the air conditioning is working very well.
Cars haven’t got much thermal insulation, so it’s hotter in the sun.
Where we are, about 60 miles south of Brisbane, it’s 30ºC every day in summer for about 3 months.
The ventilation is then set to maximum recirculation, so as to recirculate cooled air.
Haven’t died of it yet, there’s no risk of carbon monoxide poisoning from being on maximum recirculation because what’s called ‘maximum’ recirculation is still only partial recirculation, and the manufacturers know why.
Present-day cars are also very well sealed against exhaust fumes coming inside.
You could also get the windows tinted; it helps to keep the heat and glare out.
You should be able to buy rolls of DIY window tint film to slap on yourself for about £8 per roll.

[alan s]

Mine has that useless non covered glass sunroof which could only have been thought of by someone who doesn't live in the tropics. I had several days in the mid 40s last summer as I'm about 400 klms north of Clogzz and I found that by fitting a couple of those mesh window shades to the inside of the sunroof, it made it a bit more tolerable particularly when it was up to 50 on one trip I did.
From memory, about 4-6 degrees at the vent is acceptable, but also remember that air/con is not supposed to be used as a cold wind blowing right on you, but more as a means of reducing the air temp inside the vehicle. I use these mesh vents on both side rear windows as well as the sunroof and in really hot weather I also pull up the rear blind also, anything to deflect the sun.


Alan S

[_kid_]

Thanks for the response

Before i measured the temps myself, a garage measured the temp to 6.5c. I rang around a few air con regass places and some refrigerant engineers, with the responses varying from "6.5c is not cold” to "i don’t believe anyone who says they can reduce it much below 6.5" the impression i got from speaking to the different people was those who knew what they were talking about said anything around 6.5 was fine, and did not want my money. 8)

So who is right? Having measured the temps today the temp was showing around 6.5c (with slight variation either way) with the car moving.

Is it worth a regass? I know someone who will do the job (ie measure content, leak check, vacuum and the add oil, dye refrigerant) for £40.

[alan s]

I'm one of the first to admit only a very vague knowledge of the intricacies of how climate control systems work, but I do know refrigeration fairly well, and the criteria for car air/con was usually based on upper and lower levels as regards temperature.
4 being optimum and < 7 maximum. Now a car showing a constant 7 will be marginally acceptable in a a climate that is just too warm to be comfortable but will begin to struggle once the ambient gets above that point, which to me describes the situation you have at present. It must also be remembered that a stationary car will not get down to temperature for several reasons including the lesser volume of air passing over the condensor due to it's only movement being generated by the fans and secondly that it will also be limited in the volume of refrigerant being circulated due to the lower revs of the engine and hence compressor. I point that out to explain the discrepancies in readings at times and you wouldn't be the first to get caught out by them.
As regards checking the gas levels, you should have a sight glass on top of the receiver dryer. Does it show much or any bubbles in it when the system is operating? If so, there's your first clue to gas volume. Possibly the surest way to know what's happening is a set of gauges fitted to the compressor and if it's showing extremely low suction side readings, that would confirm either low gas or a possible partial blockage. An associated excessive HP reading at the discharge port would prove moisture or possible blockage.. Before you get anyone pouring tracer dye into the system if there are signs of loss of gas, take a look around the system and look for telltale oil leaks. If you find one at a fitting, chances are the "O" ring is either dead or the fitting needs tightening. If possible, try to get visual access to the T/X valve usually behind a cover plate and where all the pipes enter the evaporator under the dash. Too many of these "today" refrigeration tradesmen are tracer dye happy. It is something supposed to be used as a last resort not first line of attack when looking for leaks. I've seen systems almost full of the stuff and the systems still leaking, so it gets used when all else fails and not before. If they want to charge brain surgeon rates, they should have bran sugeon skills, knowledge and equipment and should in 99% of cases trace the leak with a detector and get it before they send the car off. Tracer dye is a good excuse to get you back for a second job or a supposed tradesman not following good trade workshop practices. It's also worthy of note that excessive oil charges can affect the efficiency of the refrigeration and as an average compressor only takes around 140 mls of oil, it doesn't take too much imagination to figure the effect of a series of ongoing injections of tracer dye are going to have.
Get back to me on the bubbles in the sight glass before we go any further down that track.

The previous repairers diagnosis; I've been thinking about this, hence the admission that I'm more into the refrigeration side than the climate control complications, but being practical about it, I notice on my Xantia that as the weather cools off, I can tend to get a slightly different odour coming from the climate system suggesting to me that perhaps the heater is brought into the act at certain times to "adjust" the temperature to stay within the boundaries of what has been selected (say 20 degrees and the refrigeration pulls it down to 18 so the heater fires up until it hits a temp that triggers the sensors and then switches off the heater and on the compressor) and if this is the case, then I wonder if his comment on the "water valve" was in fact referring to whatever they use to control the flow of the hot water into or through the matrix?
If this was the case, this would also show on a set of gauges as a higher back pressure as well as a higher head pressure. If you have any confirmation of this, it may help.

Hope that helps get you a bit closer,


Alan S