Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: vrba on 06 July 2008, 21:39:48
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Does anyone know for what is this little thing mounted on the AC pipe.
It’s on the bottom of the car you can see it when you look from beneath, the jack that comes in has 4 pins and I think that this is the main reason for my vents freaking out cause today I see that all cowered in green thing from AC cause somewhere is a leak so I start to clean the jack and few times I plug and unplug the jack vents ware all fine (after 6 months) so I thought finally I found what was wrong, started the car vents all not working (OK) temp raised to 97 fans kicked in BUT they stuck (working) again [ch61516]. So now I think that the problem is in that little silver thingy.
so when the jack is off vents are not working so this has something to do with them
Sorry for bad picture I didn’t have camera when I was working
(http://img397.imageshack.us/img397/9030/87681574dx4.th.jpg) (http://img397.imageshack.us/my.php?image=87681574dx4.jpg)
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a camera phone any good? need more info, i think ? sorry
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tomorrow than
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This thing in the middle with wires on it, what is it purpose, what this does?
(http://img508.imageshack.us/img508/9172/p7070007os3.th.jpg) (http://img508.imageshack.us/my.php?image=p7070007os3.jpg)
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Looks like a/c pressure switch :-/
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what happens if that is out of order?
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If the pressure switch don`t work the a/c compressor won`t cut in.
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ok, but can this effect my vents working and cause they are stuck and they work all the time. as i wrote above when i was messing and with that switch and cleaning it all the sudden vents fix them self. but they are stuck again and now my a/c wont work. i have a gas leak so i was thinking that there is not enough gas in system and that that is the problem for ac not working
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lack of gas will disable compressor.
Entirely unrelated to your vent problem.
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evening all, arent the vents vacume operated?
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but the strangest was when vents fix them self when i was messing with the jack.
that's why i ask questions about this part and does it have some connection with all the vents
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Hi Stjepan,
First, so that everyone understands what you are trying to describe, you need to refer to your "vents" as fans, and the "jack" as a plug. In the case of what you are describing, it is actually a free socket, but we still call it a plug. English is not a logical language!!! I think your English is very good.
We do have ventilators, which can be fans, but to we English, the vent in this context generally means the slots where the air comes out to blow into the car or up to the windscreen. We also have jack plugs, but these are generally for audio units or low voltage power supplies.
A jack is what we lift our cars up with.
Now to your problem.
The item you are asking about is the high pressure switch for the air conditioning refrigerant compressor.
It is a two stage pressure switch. As the pressure rises in the high pressure output from the compressor, if the pressure rises too high because the refrigerant is getting too hot, because maybe the cooling for the condenser is not enough with the fans on half speed, it switches them to high speed. (They will already be running half speed if the air con is switched on)
If then, the pressure continues to rise, even after the fans are on full speed, then the next stage switch interrupts the feed to the magnetic clutch, and switches off the compressor.
So to answer your question, yes, if this pressure switch was faulty, it could affect the operation of the condenser fans, as could anything wrong in the plug or wiring connecting to it. Also, if it has gone completely wrong inside it, and has jammed in the fully operated position for both switches, then the compressor would not run because it would wrongly detect too high a pressure in the system and switch off the clutch.
The fact that your previous meddling around with the plug into this unit fixed the problem for a while points to something wrong in this area.
To change this switch, you will lose any gas in the system, and need to have evac and gas re charge. Do not take out the switch untill you have the replacement to fit immediately. Do not leave the system open to air.
For information, there is also a separate low pressure switch in the system to detect loss of refrigerant.
HTH
Roger
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Good post there Big R. Very informative. :y
Something to bare in mind, especially if your foolhardy enough to use one of the DIY re-charge kits on the market, any person found guilty of knowingly releasing controlled refrigerant to the atmosphere is liable to a fine of something like £30,000.
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30k :o nice one roger, :y
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roger thx for the corrections, as you all can see i'm from croatia and some things about car i don't know to say it in eng. correctly :-/ but i'm trying .
hope now everybody understands what i'm talking about :)
my system was opened to air for some 6 months or so, when the car was at mechanic, is that a big error or what.
what can be if the system was opened to air for that long after that i just refilled the system :'(
thx again
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i think it gets to much damp in the dryer, have heard this can cause the silicon chrystals to degrade and block the ac pipes! Is this correct, anybody? Dryer is beer can size canister in front of the radiator/condensor, i would be changing that i think, others will confirm. Hope helps.
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just to inform you all problem with radiator fans is solved after many months.
the problem was in hi pressure switch.
thx all of you for giving any clue's and answers
now i'm a little bit happier :)
just few more problems to sort it out and i will have a CAR :)
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Hi Stjepan,
Very pleased to hear you have at last found the problem with your radiator fans.
Re your query about having AC system open to air.
First, the oil in the compressor is not oil as we know it, it is a Poly Alkyd Glycol fluid lubricant, PAG for short. It is very hygroscopic, that is it absorbs moisture very easily from the air. This spoils it's lubricating properties, turning it into an emulsion much like the "mayo" you get in normal engine oil if water gets in that. It also makes it acidic so it attacks the metals in the system.
Second, in the system there is a filter dryer unit. This has hygroscopic crystals in it, and its job is to extract and hold any small amounts of moisture that may get into the system. If the system is open to air for very long these crystals will become saturated and spoilt so that a normal vacuum dry out will not work, and the canister will need replacement.
Third, If having been open to air, and the filter drier is not replaced, and an extended vacuum not done to dry the system to remove all the air, and the remaining contaminated PAG, and it is just filled with R134a, then all the acidic mixture with water and oxygen circulating will soon ruin all the moving parts and rot the system. Also as the mix goes into the gaseous stage in the evaporator, the moisture will freeze and block the system. This will cause the low pressure to trip until it thaws out and this cycle wil continue until the low pressure switch fails.
Before you use the air con system, have it checked out by specialist to be vacuumed for extended time and old oil out and fresh oil in and 950 grammes R134a put in.
Roger