Discussion
Just had the A/C re-gassed, all seemed well at the time, nice and cool air, but driving home i noticed that the compressor was banging in and out all the time, very quickly, as if it was not holding on.
Is there a pressure/thermostat device that holds the compressor on when needed, and then de-energizes when not needed.
If there is such a thing then any idea where it's located, and what car it's from.
I know about the relays, and will be swapping a couple over later to see if it makes any difference, but it just doesn't sound like a relay problem.
Steve.
Is there a pressure/thermostat device that holds the compressor on when needed, and then de-energizes when not needed.
If there is such a thing then any idea where it's located, and what car it's from.
I know about the relays, and will be swapping a couple over later to see if it makes any difference, but it just doesn't sound like a relay problem.
Steve.
Hac mine re-gassed about a year ago, the chap told me if the system was over filled it would have similar symptoms to being low.
The factory told me 1 kilo of gas was correct but the guy who Filled mine reckoned that on a re-fill to go for 950 grams.
I've had frozen fingers ever since!
F.C.
Oh, and the pump cuts in and out between 30 secs and a minute.
The factory told me 1 kilo of gas was correct but the guy who Filled mine reckoned that on a re-fill to go for 950 grams.
I've had frozen fingers ever since!
F.C.
Oh, and the pump cuts in and out between 30 secs and a minute.
Edited by F.C. on Friday 21st March 14:51
Been out this morning and changed a couple of relays over, the ones that are just in front of the compressor, the far left is for the compressor, the one next to it is spare according to the manual.
The relay for the compressor did have some verdigris on a couple of the contacts, anyway, all seems well now, cannot get it to do what it was doing yesterday, have set the a/c both on hot and cold and all is ok.
Fingers crossed.
Steve.
The relay for the compressor did have some verdigris on a couple of the contacts, anyway, all seems well now, cannot get it to do what it was doing yesterday, have set the a/c both on hot and cold and all is ok.
Fingers crossed.
Steve.
The easiest way to fill these is to use the sight glass on the dryer unit that is in the off-side front wheel area. They normally have a little paper cover stuck onto the top of the unit, underneath that is the sight glass. Just fill whilst running until all the bubbles dissapear.
Unfortunatly there is no easy way of checking if it's over filled, but 1kg does sound about right if a little high (it was 960gms IIRC the last time my was evacuated and then refilled).
Bad contacts I suppose could make it do what it was doing. Hope it's all fixed for you.
J
Unfortunatly there is no easy way of checking if it's over filled, but 1kg does sound about right if a little high (it was 960gms IIRC the last time my was evacuated and then refilled).
Bad contacts I suppose could make it do what it was doing. Hope it's all fixed for you.
J
This has reared it's ugly head again, seems that if you switch the A/C straight on to cold when you start up then all is fine, but if you then turn the control to get heat with the A/C still running, and then back to cold it starts to get the above symptoms, ( comp. banging in and out all the time ), and it also struggles to get the air nice and cool.
Would this be down to a valve somewhere in the system?
Steve.
Would this be down to a valve somewhere in the system?
Steve.
steve1 said:
This has reared it's ugly head again, seems that if you switch the A/C straight on to cold when you start up then all is fine, but if you then turn the control to get heat with the A/C still running, and then back to cold it starts to get the above symptoms, ( comp. banging in and out all the time ), and it also struggles to get the air nice and cool.
Would this be down to a valve somewhere in the system?
Steve.
Steve,Would this be down to a valve somewhere in the system?
Steve.
There is a trinary switch (as opposed to valve) this is a very important part of the system because it protects the compressor from damage. You need this, and it must function properly. The trinary switch monitors pressure on the high pressure line from the compressor. If the pressure goes too high it opens the compressor clutch's electrical control circuit until pressure returns to normal(this is the clicking noise you hear) It also turns on an electric fan on the condenser to bring the pressure down. Its third function is to cut off the compressor in the event of a refrigerant leak, which is indicated by a too-low line pressure.
There is also a low pressure switch mounted on top of the drier unit.(LHS front under front clam on M400)
You could as a matter of experimentation only with the air con on full blast short the two wires on top to see if the compressor starts up for a short period of time and obviously not when driving, this will give an indication of one of the above faults or indeed a faulty switch (not likely).
Messing with the trigenic switch I would leave to the “experts”. I can't stress highly enough the dangers of shorting this switch as it could result in disaster, the pressure in the system could easily reach 500 psi if there is a fault present hence the need for the switch.
Disclaimer: I accept no liability whatsoever for the above drivel, the fact that I have done it to check my system is no indication that it will have the same effect / result on yours. you have been warned
F.C.
Edited by F.C. on Sunday 6th April 12:13
Just to put some closure on this, had the A/C system re-gassed again, drained/vacuumed/re-filled, and found that there was actually well over 1000g in the system, in fairness to the guys that did it, they said that their equipment had recently been re-calibrated, and found to be out.
Have had it re-charged with 800g, (seeing as there is such a mystery of the amount that goes in ), all seems well, no banging of the comp. and air nice and cool.
Will run it like this for a while, if all seems well then brilliant, but if it starts to struggle then I will go back for a top-up, foc of course.
Steve.
Have had it re-charged with 800g, (seeing as there is such a mystery of the amount that goes in ), all seems well, no banging of the comp. and air nice and cool.
Will run it like this for a while, if all seems well then brilliant, but if it starts to struggle then I will go back for a top-up, foc of course.
Steve.
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