A/C issue....... (cls 219)

j4gg4

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Morning gentlemen,

I have a A/C issue which has never worked since ive owned the car for 3 years, the engine was removed as i bought the car so its possible the A/C just leaked out.

But on STAR i get the dreaded B1205 error...refrigerant pressure is too low. Obviously in this heat we are all getting this july its very much needed at the moment and my kids literally roast slowly in the back of the car so we havent gone on long trips yet but one coming up in august. If its not fixed by then i will have to let the wife roast in the back ;)

Right so this error, does this error pop up when you simply run out of A/C gas? or does it pop up when there is a actual issue ie.. broken sensor? or both? the A/C just blinks red, doesnt blow cold air and star doesnt clear the B1205 error. If there is no gas, does star really know this? ie.. would error clear if it was a simple regass?

Im wondering if its worth it to simply pay £40 to get a regass or is there anything else i can do to establish if theres a further problem?
 

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Your first move is to get a re gas and a leak test, there is no other way.
It is not good leaving the systems empty for long periods.
 

star

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Start with a regas, but ask if the "garage" if they can clear the fault as it still will not work until this is done.
 
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cleverdicky

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I have mentioned before but worth repeating.
This is stating the obvious a bit Im sorry,.
Imagine the car AC system as two halves. When the compressor runs, it sucks gas from one side and pumps to the other raising the pressure. When at a high enough pressure it turns to liquid and fed to evaporator through tiny orifice.

If there is the tiniest part, scale, and especially moisture (from air) etc. it will partially block the orifice. However the compressor wont know this and keep working.
Because of any blockage, the gas will build up on the high pressure side and drop very low on the low pressure side. Another potential for this on an older system is the filter / drier.
Therefore either side may trip a pressure switch and shut it down.

So if you have had the system open for any reason, and no 'fault' is apparent. Dont just get them to top up, but remove gas completely. And if possible flush through.
 

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I have mentioned before but worth repeating.
This is stating the obvious a bit Im sorry,.
Imagine the car AC system as two halves. When the compressor runs, it sucks gas from one side and pumps to the other raising the pressure. When at a high enough pressure it turns to liquid and fed to evaporator through tiny orifice.

If there is the tiniest part, scale, and especially moisture (from air) etc. it will partially block the orifice. However the compressor wont know this and keep working.
Because of any blockage, the gas will build up on the high pressure side and drop very low on the low pressure side. Another potential for this on an older system is the filter / drier.
Therefore either side may trip a pressure switch and shut it down.

So if you have had the system open for any reason, and no 'fault' is apparent. Dont just get them to top up, but remove gas completely. And if possible flush through.

If the system is empty, then it has to be dried out, It may need a new drier if empty too long.
 

cleverdicky

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Correct. 'Driers' are made from a ceramic desiccant material and cannot be cleaned.
If this system has been left open for some time it will need a good flush through and pressure checked.
 
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j4gg4

j4gg4

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Thanks guys,

I have STAR and so i can check it myself and i have attempted to erase the fault without luck. The engine was removed and replaced but i would not say the pipes were breathing fresh air for too long.

I will see what the cost is for a flush, but i believe normal regassing the pressure check procedure comes with the re-gas?
 
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j4gg4

j4gg4

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Just to update, got the AC pressure tested today and the mechanic found no leaks. He filled it up with aircon gas and tested it. Still had the flashing AC light problem and no AC. He told me the high pressure switch will prob need to be replaced.

Got it home hooked it to star and deleted the low pressure fault i had on there before. This time it deleted OK and now AC has a nice TICK next to the module.

Checked the AC and still no cold air coming out. No faults either...ermmmm Is there anything else i can do with no fault codes...no leaks...full GAS?
 

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Look at actual values and see what the refrigerant pressure sensor is reading
 

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Look at actual values and see what the refrigerant pressure sensor is reading

Thats what I did on my CL just run the live data and what is wrong or could be comes up
 
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j4gg4

j4gg4

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Here is pics from star....




My friend told me to touch the AC pipes in the engine, and they wasnt really cold...not much anyway. Possible air in the system?
 

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You need to go a bit further on in STAR, I forget which menu, AC control possibly
 
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j4gg4

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You need to go a bit further on in STAR, I forget which menu, AC control possibly

The refrigerant pressure is showing as 9bar in the pic... it fluctuates from 7bar to 11bar..

Shouldn't it be a lot more than this?
 

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The refrigerant pressure is showing as 9bar in the pic... it fluctuates from 7bar to 11bar..

Shouldn't it be a lot more than this?

Yes after a recharge mine is 12.3 bar, could there be too little gas, that was the fault with mine
 
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j4gg4

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Yes after a recharge mine is 12.3 bar, could there be too little gas, that was the fault with mine

I will go back to the garage and ask them to use the vacuum on it and then recharge it again. Because my friend who does his own AC when needed said if the pipes are not cold then there is air in the system.
 

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OK do make sure that they put the correct amount in, many places do not know the correct amount, kwikfit do not know on most
 
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j4gg4

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OK do make sure that they put the correct amount in, many places do not know the correct amount, kwikfit do not know on most

I have no idea what the amount is, neither do most places i dont think.
They are just making a quick few quid. I nearly went to kwik fit but when they told me they were the cheapest around and the best i did a runner because i knew others were cheaper.

I went to these http://www.f1autocentres.co.uk/

What they did was this...

Hooked nitrogen up to the aircon system and left it on for 10 mins..checked the pressure to see if it was losing any pressure on the guage and to hear any hissing noises to indicate a leak. (i know most places use dye to check for leaks).

Anyway after the all clear he said it was sealed system and he will gas it up. The gassing took 15 / 20 mins or so and he used a rather big machine with all flashing lights on.

I did tell him the engine was removed from the car a while back and the aircon had never worked. So i presumed he would know there would be air in the system and probably no lubricants/oil. However he did not do a vacuum on it which i will have to tell them to do tomorrow.

Great video here i found:

http://www.youtube.com/watch?v=lglPJuBXVeE
 

television

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They should remove what gas is in there and weigh it as this gives of info, for if it was correct they know to look else where
 

cleverdicky

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Pressure readings will NOT indicate how much refrigerant is in there.
Presure fluctuates with temperature. A hot day / engine will read higher than a cold one.

If pressure readings are to be used, then measure both suction and discharge while running.
 
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j4gg4

j4gg4

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UPDATE:

after 24 hours the A/C started working....
ODD?
 
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