Xantia air con question

[xantia_v6]

If the compressor clutch is engaging, the pipe from the evaporator to the compressor should be cold, close to freezing, if the refrigeration system is working OK.

[Mandrake]

I am reading up about the heater controls now. On the way home fiddling around with the temp controls, the air was cooler with the slider set at 22 than blue. It was 24 outside, with the slider on blue the air was 18, with the slider on 22 it was 14. (On 24 it was 24, on hot it was over 70) Very odd. Will see if it happens again tomorrow.

Don't set the temperature slider to the blue or red regions in conjunction with the auto fan speed. If you do this, the fan will always run at a very slow speed and you won't get much cooling/heating.

Why it is designed like this I don't know but all my Xantia's have behaved this way. If you want to leave the fan on auto don't set the slider below 18, otherwise set the fan speed manually. Setting to the blue and red regions forces the mixer flap to go to fully cold or fully hot regardless of the measured cabin temperature, however it will only have any real effect if you set the fan to manual speed control, as auto runs the fan so slow in this situation.

You didn't answer whether there is plenty of air flow out of the vents ? A somewhat common problem on Xantia's is that the foam gaskets that join sections of the air vents inside of the dashboard rot away leaving gaps that you can put your fingers through in the air pathways deep inside the dashboard. This greatly reduces the amount of air flow coming out of the vents as some of the air flow gets lost inside the bowels of the dashboard.

Pity you can't get it on a Lexia, that would have made it a lot easier to figure out what is happening. So you're measuring 14 degrees at the vents, using what ? If you leave it running like this and then watch the compressor clutch for a few minutes does the clutch stay engaged or do you hear it turning off and on every few minutes ? Did you try xantia_v6's suggestion of checking the temperature of the return pipe to the compressor ? It should be cold enough to cause condensation to form on it in most circumstances.

[Jaf]

Ok so going back to this. Thanks for your ideas.

Clutch stays engaged for 20 mins at tick over, turned her off then. Pipes from the compressor are not cold at that point. Using temp gauge put in the vent the temp gets down to 22 or so, outside temp 32ish. With air con off the vent temp goes up to 34. On a longer drive, over an hour, the vent temp gets down to 11. Assume the compressor pipes are cold then but didn't stop to see.

The air coming out the vents seems strong to me. Compares fine with other cars anyway.

I have ordered a Lexia today, from easydiagnostics as recommended here, so hope to have some answers soon. Can do the keys too. Yay.

Also remembered that I kept the old compressor when it was changed 4 years ago, so if it's not an electrical fault I could do the seals and swap it back.

[xantia_v6]

If the compressor is engaged but the low pressure pipe not getting cold (below 5 degrees), then the problem is in the refrigeration system, not the electronics. An expert should be able to diagnose it from the high and low side pressures.

I have been driving my Xantia in 30 to 35 degree temperatures for the past week, and although not quite as efficient as the XM, the A/C has been perfectly adequate.

[Jaf]

Thanks. Unfortunately I have struggled to find anyone who knows more than how to connect the air con testing machine. Been through 4 air con places. So I am having to learn all about it. The one who managed the find the leak 4 years ago, others failed, is the who said the compressor and pressures were fine. But I didn't see the machine or the numbers. Idiot. He said its electrical. The last one, with the failed Lexia session, said the dryer was blocked without actually testing anything!

So if the air con is on, regardless of the temperature required, the compressor pipes are cold? Then if hot air is required the cold air mixes with hot air passed over the heater matrix?

From the videos I've watched, the compressor uses pistons to compress the gas. It doesn't really look to me like it could only half work. I guess a kinked pipe or blockage could cause it to be very inefficient.

There are several sensors, the evaporator one seems to disengage the clutch so I don't think it's that. The one with the tiny fan, behind the time clock, is working. What I wonder if is the cabin temp dial thinks I am asking for warm air rather than cold. Or the cabin thinking it's colder than it is. Anyway once I have the Lexia I shall find out!

[xantia_v6]

The only control that the electronics have of the refrigeration system is to engage or disengage the clutch. Control of air temperature is done by moving flaps to mix ratios of hot and cold air.

If the refrigeration system is not working effectively, there could be several causes, such as insufficient refrigerant, or blocked expansion valve, or insufficient airflow over the condenser, but it really needs some old-school diagnosis. Try to find someone who has been in the business for 20 years, before all-in-one recharging machines were invented.

[Jaf]

Hmm yes. Think I would need to go to a city to find someone. Had to go to Lorca to find an engine rebuilder.

Anyway I am quite enjoying learning about the system. As I understand it's a bit more complicated as strictly speaking I should call it Climate Control rather than air con. Therefore the flaps are electrically controlled by the climate ecu. If there is a problem with one of the sensors then it all goes hay wired. The Lexia apparently will allow me to set fan speed, temp, turn it on/ off.

I am trying to be methodical. I have had the gas side tested, though I will definitely be watching the air con gassing/ testing machine next time to see the high/ low pressures. Pipes and condenser look ok. No idea how to check the expansion valve, I shall look it up. Next is electrical. Then put the old compressor on, with a new dryer. It would be a lot, lot, better with an expert

[Jaf]

So this is 2 years old. My Lexia didn’t show any air con faults. I gave up!

A month ago I found another, 5th garage. The gauges showed the high and low pressures were off...internal leak in the compressor. New compressor (and dryer) fitted and my air con is lovely.

Should’ve trusted the Citroen fella’s instinct.

Still doesn’t turn on automatically with the demist setting. Not a problem, just interesting.

[xantia_v6]

So this is 2 years old. My Lexia didn’t show any air con faults. I gave up!

A month ago I found another, 5th garage. The gauges showed the high and low pressures were off...internal leak in the compressor. New compressor (and dryer) fitted and my air con is lovely.

Should’ve trusted the Citroen fella’s instinct.

Still doesn’t turn on automatically with the demist setting. Not a problem, just interesting.

Good to see you finally got it sorted.

The automatic A/C with demist was introduced quite late, maybe 1999?

[Harlequin]

I now have a Xantia again, first time in years, and I have to manually select the A/C in any setting to get it to work

[Mandrake]

I now have a Xantia again, first time in years, and I have to manually select the A/C in any setting to get it to work

Oh the hardship of 1st world problems

Of the three Xantia's I've owned and two others I've driven none of them turned the A/C on automatically in any modes like demist.

I don't really see what the issue is - if I want to demist the window I'm clever enough to press the A/C button in addition to diverting the air at the windscreen ? I don't necessarily want the A/C running the whole time the diverter is set to the windscreen. Sometimes I just like fresh air coming in via the demist vents rather than blasting me in the face...

[Jan-hendrik]

How long does it take to run a diagnostic test with the Lexia on the heating / air conditioning system? Is there a document pertaining to this on this forum? Help and pointers appreciated.

[xantia_v6]

How long does it take to run a diagnostic test with the Lexia on the heating / air conditioning system? Is there a document pertaining to this on this forum? Help and pointers appreciated.

Are you asking about a Xantia or XM? They are different systems, and there were at least 2 different types of A/C in the XM and at least 3 in the Xantia.

In both cases, they are connected to Lexia in the normal manner, but the XM fully automatic system is rather slow to respond and does not give much data compared to some of the Xantia A/C ECUs.

The A/C ECU is one case where it is important to give Lexia the correct RPO (and perhaps VIN) in order that it knows what sort of ECU it is trying to communicate with. Even then, some Lexia clones don't like talking to some Xantia A/C ECUs.

[Jan-hendrik]

Thank you for your quick response.
I am asking about my XM (details listed with avatar) which has Fully Automatic Refrigeration.
I once tried to have the Lexia talk to the A/C ECU, but it took forever to get anything meaningful and I wondered if that was normal.

[xantia_v6]

The diagnostics for the XM fully automatic system are very slow, and not very comprehensive. I think that the ECU only talks in very slow blink-codes.