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[Omega Nige]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

[Alnico Blue]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

Had a similar situation with a previous omega of mine . A/C was not working & compressor was not engaging  . . .took it to my usual garage/MOT man. Gas pressure was zero.  He done a full vac & refill etc. & A/C then worked fine . BUT only lasted for a few weeks before it started to not get fully cold & eventually packed up again , so obviously a leak . A/C systems deteriorate when faulty & not used especially the seals.  When recharging they normally put in a dye that can be seen with a special light to locate leaks .  HTH 

[Migv6 le Frog Fan]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

Yes. 

[GrahamT]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

One interesting thing to know before you top the system up is if the system is holding any pressure at all.

When I got mine the gas level had been allowed to drop, over time, to just below the point of letting the compressor kick in. I topped mine up and its been fine ever since.

If you go to Halfords then can check using a gauge what pressure is in the system. I wouldn't normally recommend them but its not hard to unscrew the cover and locate a gauge on a quick release port. It's free and at least it will give you a little more information.

Thanks

[biggriffin]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

Yes. 

This^^^^^
Also a little squirt of WD or similar into the pulley also helps.

[biggriffin]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

One interesting thing to know before you top the system up is if the system is holding any pressure at all.

When I got mine the gas level had been allowed to drop, over time, to just below the point of letting the compressor kick in. I topped mine up and its been fine ever since.

If you go to Halfords then can check using a gauge what pressure is in the system. I wouldn't normally recommend them but its not hard to unscrew the cover and locate a gauge on a quick release port. It's free and at least it will give you a little more information.

Thanks

.

Get it put onto a proper dalek, or use a set of hp/LP/fill gauges and vacuum pump. Halfords cans are a total waste of £40.  Considering some places charge £45 for a full hook-up on a dalek. Which will drain the system, and re-vacum it, a decent place will even pressure test with nitrogen.

[Sir Tigger KC]

I think any decent AC place will pressure test the system before filling it up?

[biggriffin]

I think any decent AC place will pressure test the system before filling it up?

Some places, just let the dalek do it, but that's a vacuum test, not a pressure test, if you ask, they say " machine does that sir" 
System needs to be purged, then, filled with nitrogen under pressure, to check for leaks, if no leaks then pulled down and gassed.

[Kevin Wood]

I think any decent AC place will pressure test the system before filling it up?

I'd hope so, or they are breaking the law.

[biggriffin]

I think any decent AC place will pressure test the system before filling it up?

I'd hope so, or they are breaking the law.

.

Most of the large chains rely on the dalek, it emptys first, then induces a vacuum, which is held for time, as long as it holds, it will refill with gas and small amount of pag-oil and dye.. A pressure test is more revealing for small leaks.

[Omega Nige]

I have checked and I have enough gas in the system but the compressor isn't engaging. Checked and cleaned the connector plug and socket. How can I check that the signal is being sent to energise it?

Thanks 

[biggriffin]

I have checked and I have enough gas in the system but the compressor isn't engaging. Checked and cleaned the connector plug and socket. How can I check that the signal is being sent to energise it?

Thanks 

Check eco is off, and check fuses. also turn temp to Lo..

[GrahamT]

I'm looking at topping up the air con but my compressor clutch is not engaging. Before I delve into it will low gas pressure disable the compressor so I will need to top up the gas to get it to run?

Thanks 

One interesting thing to know before you top the system up is if the system is holding any pressure at all.

When I got mine the gas level had been allowed to drop, over time, to just below the point of letting the compressor kick in. I topped mine up and its been fine ever since.

If you go to Halfords then can check using a gauge what pressure is in the system. I wouldn't normally recommend them but its not hard to unscrew the cover and locate a gauge on a quick release port. It's free and at least it will give you a little more information.

Thanks

.

Get it put onto a proper dalek, or use a set of hp/LP/fill gauges and vacuum pump. Halfords cans are a total waste of £40.  Considering some places charge £45 for a full hook-up on a dalek. Which will drain the system, and re-vacum it, a decent place will even pressure test with nitrogen.

Note I said let them check the system pressure. Not fill it.

Talk about a massive over reaction to a very simple and free check. As most places that refill your aircon will charge you something even if the system can't be recharged.

[TheBoy]

The only viable way to check how much is in there is to suck it all out, and see what you have.

If you want to know if you have enough in there to activate the pressure switches, a multimeter if a free test, and more conclusive than a spotty yoof with a half-arsed gauge

[Omega Nige]

Switched off eco, set to low, fans on full, fuse ok. Still not switching in the compressor  . Any ideas?

[biggriffin]

Switched off eco, set to low, fans on full, fuse ok. Still not switching in the compressor  . Any ideas?

I would say no refrigerant.

[Kevin Wood]

Either high pressure or low pressure will prevent the air conditioning compressor from engaging. I can't remember where the pressure switch is located but it rarely gives problems, and replacement would require the system to be vacuumed out and refilled anyway.

Do the front fans run at slow speed when the air con is switched on? If they do, but the compressor doesn't engage, I'd suspect a problem with the compressor clutch (you can get to the wiring to this from underneath the engine). Otherwise, assuming the fuses are OK, the most likely issue is low refrigerant but it might be worth checking if relay K60 is engaging. This is in the triangular box by the passenger side front wing. On the row of relays closest to the wing, it's the 5th relay back from the front.

If you remove this relay, take its' cover off, then re-insert it, you can watch for movement when you turn the air con on. You can also push the contacts together with the ignition on and you should see the compressor clutch engage and the fans start.

[biggriffin]

High pressure switch is located, on the pipe, just above the under tray, in front of compressor, has a two wire plug on, only replaced one, £65.00.

Earlier models had a high and low pressure switch.

[mandula]

My A/C has also stopped working.

After winter when hot day I noticed lack of cold air coming from nozzles and compressor did not engaged.
I took it to A/C service where they refilled the system and after that A/C worked fine (cold air coming and compressor engaged), until the next day it did not work again. No cold air and compressor does not engage.

I viewed live parameters with OBD-tester via phone application and it said there is A/C-pressure of 1000 kPa (~10 bar).
I could also test A/C-relay (I don't know which relay) from this application and it made fan to start up at engine bay .
I've measured that compressor magnetic clutch resistance is OK 4.3 ohm.
Fuses are OK.

I assume there is no leak because of A/C-pressure reading says there is pressure (does that pressure reading sound about right?).
Is there a way to force engage compressors clutch from relay box, to check there is no open circuit on wirings?
What else could I check before I go back to A/C-service for troubleshooting and giving away my money?

I don't know are these related, but just after A/C-service car's Check control informed me about "Check oil level". There was oil enough and that message keeps coming and going randomly many times a day.

[LC0112G]

My A/C has also stopped working.

After winter when hot day I noticed lack of cold air coming from nozzles and compressor did not engaged.
I took it to A/C service where they refilled the system and after that A/C worked fine (cold air coming and compressor engaged), until the next day it did not work again. No cold air and compressor does not engage.

I viewed live parameters with OBD-tester via phone application and it said there is A/C-pressure of 1000 kPa (~10 bar).
I could also test A/C-relay (I don't know which relay) from this application and it made fan to start up at engine bay .
I've measured that compressor magnetic clutch resistance is OK 4.3 ohm.
Fuses are OK.

I assume there is no leak because of A/C-pressure reading says there is pressure (does that pressure reading sound about right?).
Is there a way to force engage compressors clutch from relay box, to check there is no open circuit on wirings?
What else could I check before I go back to A/C-service for troubleshooting and giving away my money?

I don't know are these related, but just after A/C-service car's Check control informed me about "Check oil level". There was oil enough and that message keeps coming and going randomly many times a day.

That's far too high if the compressor isn't actually running. From memory (admittedly on the Carlton) it's about 3-4 bar when not running, up to 8-10 bar running on the HP side. Omega may be a bit different, but 10 bar static can't be correct, so assuming your Reader is working properly I'd suspect either the sensor or wiring to the sensor.

Or perhaps more likely, it's reading 1Bar (i.e. Atmospheric), there is no gas in the system again, and you've got a big hole in the AC radiator. 

[Kevin Wood]

The Omega has no pressure sensor anywhere in the A/C system so there is no way for this data to be presented by OBD. I think it's a red herring.

[mandula]

It really is 1000 kPa, it sure might be 100 kPa so it might be normal surrounding pressure.

I read somewhere that there is some analog pressure sensor that gives pressure reading in voltages to ECU or what ever is controlling A/C system?


Well, I made some testings and took hats off from relays K60 and K87 under bonnet. Car was running.

When I pressed contacts on relay K87, both fans switched ON.
When I pressed contacts on relay K60, both fans switched ON and compressor engaged.

So I believe all wirings are OK.

I believe now I have about three options left and one extra option:

1. Pressure too high (I don't really believe so because A/C worked fine for one day).
2. Pressure too low.
3. Pressure sensor/switch defected.
(4. take it to the service  )

Maybe next I'll connect OBD-reader again and check if pressing pressure valve gives me any PUFF and if so, does that affect the reading I see on live parameters..

[mandula]

Ok, almost none PUFF when pressed valve. To the service it is then 

Next time I test that method first and dont trust any stupid false nonsense readings that applications give..

[biggriffin]

It really is 1000 kPa, it sure might be 100 kPa so it might be normal surrounding pressure.

I read somewhere that there is some analog pressure sensor that gives pressure reading in voltages to ECU or what ever is controlling A/C system?


Well, I made some testings and took hats off from relays K60 and K87 under bonnet. Car was running.

When I pressed contacts on relay K87, both fans switched ON.
When I pressed contacts on relay K60, both fans switched ON and compressor engaged.

So I believe all wirings are OK.

I believe now I have about three options left and one extra option:

1. Pressure too high (I don't really believe so because A/C worked fine for one day).
2. Pressure too low.
3. Pressure sensor/switch defected.
(4. take it to the service  )

Maybe next I'll connect OBD-reader again and check if pressing pressure valve gives me any PUFF and if so, does that affect the reading I see on live parameters..

Basically you've over analysis's a simple problem, you need to see if the system will hold refrigerant, if it will, then look into why it's not working, my money is on either leaking condenser or leaking compressor, or holes in pipes under battery tray.

[mandula]

Yea, as stated above your post I noticed there was almost none stuff in the system.

I was confident that I could trust the live parameter reading of A/C pressure. I was wrong. But now atleast I know better how my A/C system works 

[Omega Nige]

Hi all sorted, see my thread in the electrical section, thanks for your input

[Omega Nige]

Hi, thanks for your help all sorted see my post in the electrical section