Selective heating ...

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Jshodgson
Posts: 140
Joined: 18 Oct 2004, 22:59
Location: Torquay
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Selective heating ...

Post by Jshodgson »

My heater works through the central vent but does not work through the windscreen or side vents. Through these it will only blow cool air. The air coming through the central vent is nice and hot.

Any ideas?
Had (Saxo VTR 1999 (T) LPG converted - do not ask!!!)
Had (Xantia LX TD 1995 (M) 144,000 miles)
Had (Xantia TD Estate (N) 147,000 miles !)
NOW GOT Picasso 2.0HDi (02) 96,000 miles
mike_zr7
Posts: 23
Joined: 25 Jan 2004, 01:52
Location: United Kingdom
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Post by mike_zr7 »

I once had a similar problem with a Fiat Tipo (never again). The problem was a flap inside the dashboard had broken and this stopped the hot air circulating.
1996 Xantia 1.9TD 78.000 miles, not yet run in
johnway
Posts: 192
Joined: 13 Sep 2005, 02:59
Location: United Kingdom
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Xantia Heater

Post by johnway »

Hello,
We share the same problem. My '97 Xantia VSX 1.9TD blows cold on the feet, but warmish through the upper front vents (plus I am experiencing blower problems at the moment). The air distribution unit is at fault - probably stuck vents and looks like a B....r to get at. In the Haynes manual it says first remove facia, which is preceeded by first remove steering wheel, which is preceeded by first remove airbag, which is first preceeded by first disconnect battery and wait at least 10 mins before doing anything. In other words, expect at least 2 days stripping half the B. car to gain access, sort out and attempt to replace all connections,screws, bolts and everything else, then re-code car and radio!! The heater control unit and stereo seem to be easily removable and I would be interested to know if anyone out there has managed to get at the air distribution unit just by removing these and be able to attack the vents?
All the best,
John.
My chariots : 2002 Pug 406 110 HDI Executive Estate 138K
1995 Citroen AX 1.0 Debut 26K
I Blame it all on my Dad!! (Sadly had to give up driving & his 2nd BX) but Mum still has a C1.
chrissib
Posts: 8
Joined: 01 Dec 2005, 09:22
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Xantia Heater

Post by chrissib »

I have exacly the same thing in my xantia sx HDI a/c.

Heater blows warm (could be warmer) in face vents but cold at footwells. The blower itself appears quite weak, and jumps from slow to fast without anything imbetween. The temp guage gets to normal since replacing stuck stat. As warm air is in the car assume temp is ok but as blowing cold, would assume vents not blocked. Surely the whole facia doesn't need to come off... does it?
Regards
Chrissib
xantia HDI sx 2000 1999
Suffolk, England
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fastandfurryous
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Joined: 07 Jul 2004, 17:57
Location: On the road, travelling at high speed. Meep Meep.
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Post by fastandfurryous »

In similar style to the 405, the entire facia does indeed have to be removed. I'm now on my second time of doing this on my 405. The way modern cars are made is to fit the heater unit to the inside of the facia, and then fit the whole thing as an assembly, through the front door apateure. Because of this, you have to pull the facia off to get to the heater box.

As to the problem with no heat to certain vents, many modern heater units are very badly designed, and the airflow paths mean that air from certain areas of the matrix ends up in different places.

The next problem is that the heater matrix is a prime location for silt and general crap in the cooling system to accumulate. What happens is that the lower part of the matrix fills with crud, leaving that part cold. The upper part of the matrix still has flow, and thus gets hot.

Air that goes through the top of the matrix ends up coming out of the facia vents, and the air going through the cold bit of the matrix ends up coming out of the foot vents.

This was/is exactly the problem I have with the 405 at the moment. It's the second time I've had the facia out (can now do it in 40 minutes!) as the matrix I've just pulled out has lasted 14 months before filling up with crap. No amount of flushing through the inlet/outlet pipes has had an effect, so the only thing to do was have the matrix out.

I'm also in the middle of modifying the heater unit so that you can have hot air on your feet and cold air up the screen, and actually be confortable while driving, rather than what most designs permit, which is red hot air through the facia, and freezing cold feet. Not confortable at all!
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