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Old 23rd May 2020, 21:37   #11
Chuckles
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It might be the desiccant dryer. I had similar problems and thought it was the pump/compressor blocked/restricted but after changing it and then the condenser it turned out to be the desiccant.
Check with Jules he got me out of trouble with-it all.
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Old 23rd May 2020, 21:47   #12
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Quote:
Originally Posted by GP1005 View Post
Demist test shows fan changing from low to high speed (late car with just two speeds).
That's a fail for the Demist Test. The low speed fan should run continuously until the aircon is turned off. If the fan speed changes to high speed, then the system is over-pressurising. That may be due to lack of condenser capacity, typically from a degraded matrix.

This from Jules I believe.



Worth looking into - or through as the case may be.


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Old 24th May 2020, 08:01   #13
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Quote:
Originally Posted by GP1005 View Post
Compressor engages when air con selected so must have gas. Simply no chilled air at vents.
It may have insufficient gas Gary. I would call a independent mobile air con. specialist who can extract the charge and tell you exactly how much you have. If you're in Ashford, Middlesex/Surrey I can recommend one.

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Old 24th May 2020, 08:12   #14
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Worth checking the above for faulty components. Most likely would need a full vac and regas. A regas alone would not fix it.
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Old 24th May 2020, 11:46   #15
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Mine was perfect when I had the car, virtually ice cold but I have given up on my aircon now and just open the windows, here's why.

I had problems with my ZT aircon a couple of years ago, the condenser was changed two years ago after looking like the one in the picture, all new seals then regassed properly, vacuum tested for 45 minutes during the regas.
Three weeks later the aircon wasn't working, back to the specialist who again tested and used uv dye to look for leaks, nothing found so I was sent on my way again, three weeks later and the same again.
Now I just sit and sweat in traffic or open the window when travelling.
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Old 24th May 2020, 14:44   #16
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Thanks for the comments

TC - I have run the demist test again with a cool engine at tickover.
Fan off. Pushed demist and fan on full until switched off again by pushing econ (test you recommended in 2014)

Chuckles - can you change/check the desiciant without regas

SD1too - Sadly Ashford, Kent and not Ashford, Middlx
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Old 24th May 2020, 15:33   #17
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Quote:
Originally Posted by GP1005 View Post
Pushed demist and fan on full ...
Gary,

The low speed on a 2 speed system can be very noisy and mislead the owner into thinking it's the fast speed.
If your condenser is low efficiency and/or you have a low refrigerant charge (but not low enough to disable the compressor) the fan will still start at low speed then, after a time, increase to fast.
Quote:
Originally Posted by GP1005 View Post
...can you change/check the desiciant without regas ...
No. Chuckles says that to ultimately solve his problem the condenser was replaced. That makes sense. The desiccant's purpose is to absorb any moisture in the refrigerant. It will not completely stop the system cooling.

You need to check your refrigerant charge otherwise you could waste time and money on unnecessary repairs.

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Last edited by SD1too; 24th May 2020 at 15:36..
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Old 24th May 2020, 17:53   #18
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Thanks Simon
Will get an air con guy over

Gary
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Old 28th May 2020, 14:01   #19
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Air con gas was low but apparently high enough to engage compressor. Put some die in the system and regassed. Working at the moment.
Low speed fan on initially and switched to high speed once there was enough pressure in system
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Old 28th May 2020, 15:15   #20
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And use it throughout the year as well. Like a dog is not just for Christmas. Air Con is not just for summer!
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