A/C service

wotme

wotme

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From new when would you expect to have the first air con service carried out. I imagine this question applies to any vehicle and not a particular make or model, probably wrong about that but as a general rule what do you think?
 
I was told by Dometic that the hab aircon is not serviceable - that is there is nothing to service unless it breaks. Mine is now 13 years old and still works okay.

The engine-powered aircon would only need regassing when it's no longer efficient - but it should be taken to a proper servicing agent as technically they're supposed to empty the system of gas, then check for leaks before recharging. However most places just stick a refill bottle on until it gets to the right pressure - fine if there is no leak but otherwise a waste of time and money as well as not good for the environment.
 
On house A/C you just clean a filter that slots into the indoor unit, probably once a year, also give the outdoor condenser fins a brush. Don't know if vehicle habitation A/Cs have filters ?

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I think they are supposed to be regularly run as it lubricates the seals even in winter. I also heard that it can dammage the system running them when the refrigerant gas is too low.
Whether its true or not who knows I do know a new heat exchanger and compressor costs bigtime! When we had air-conditioning installed years ago at work and I asked the engineer about regassing he said domestic units shouldn't need it as the engines vibration and movement causes a certain amount of small leakage a home one doesn't have the same problem.
 
TerryL said:
I was told by Dometic that the hab aircon is not serviceable - that is there is nothing to service unless it breaks.
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It's definitely worth taking the cover off every now and then to clean all the leaves and bits out and give the condenser / evaporator fins a clean plus make sure the drain holes are clear of debris.
Also wash filters accessible from inside.
 
The Wino said:
I think they are supposed to be regularly run as it lubricates the seals even in winter.
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A very common myth.


The Wino said:
I also heard that it can dammage the system running them when the refrigerant gas is too low.
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It's certainly not ideal running them when low on refrigerant, it doesn't damage them directly, but the suction can be in negative pressure which can suck air or even worse, water in. Electric compressors can overheat too because they rely on cool superheated gas coming back from the evaporator.
 
Okay this is what I've learnt from a guy who's job it is to know about these things. Ideally the A/C should have attention every two years. Over time bacteria builds up and causes unpleasant odours, when this happens its definitely time for re-gassing. So I think I'll wait until it stinks or becomes inefficient before I shell out £130. Of course when that time comes I need to find out what particular gas I need
 
If it's the cab air con you mean then it can't be serviced. If it's not cooling very well then a regas is worth trying, this also includes lubricating oils in the refrigerant. It's worth changing the filter/drier as part of the regas but I don't know of any high street garages that will do that.
If the pressure is to low the system won't work so hard to do much damage ( pressure switch prevents magnetic compressor clutch activating).

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wotme said:
Over time bacteria builds up and causes unpleasant odours, when this happens its definitely time for re-gassing.
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The bloke should be taken out & shot. There is nothing whatsoever connecting any type of 'smell' to the actual refrigerant. If there was it would all disappear in a few seconds as in a leak.
the only thing that would cause a smell would be any type of filter on the outside air intake possibly getting muck on it. That can just be removed & changed . certainly not costing that sort of money.
 
wotme said:
Okay this is what I've learnt from a guy who's job it is to know about these things. Ideally the A/C should have attention every two years. Over time bacteria builds up and causes unpleasant odours, when this happens its definitely time for re-gassing. So I think I'll wait until it stinks or becomes inefficient before I shell out £130. Of course when that time comes I need to find out what particular gas I need
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That's expensive for a regas.
 
dunnah01 said:
this also includes lubricating oils
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No it doesn't ☝oil has to be put in by a styrup pump and is rarely needed. When the refrigerant escapes it leaves the oil behind as the oil doesn't evaporate at atmospheric pressures ?

Edit: a tiny bit of oil does come out with the refrigerant, hence why we look for oil when a system has lost it's refrigerant, but it's very negligible ?

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For cab Aircon the garage will just connect the machine to high/low pressure lines and then turn it on, the machine does the rest. First part is to evacuate all remaining refrigerant to a safe cylinder, second part will pressure test system, then last part will refill with new refrigerant and gloppy oil stuff. No human intervention is possible unless it fails at some point.
 
Richard and Ann said:
A very common myth
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I’d appreciate some confirmation of this. I’ve always thought that the system needs to be run in order to keep the seals lubricated and effective at...sealing!

I’ve been a bit concerned that the A/C has not been run for 6 weeks or so, yet don’t want to keep running the engine at idle for fear of causing damage.

Richard and Ann Do we not need to worry about the A/C system not being run then?
 
Richard and Ann said:
No it doesn't ☝oil has to be put in by a styrup pump and is rarely needed. When the refrigerant escapes it leaves the oil behind as the oil doesn't evaporate at atmospheric pressures ?

Edit: a tiny bit of oil does come out with the refrigerant, hence why we look for oil when a system has lost it's refrigerant, but it's very negligible ?
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Are you talking about normal vehicle air con or hab recon? Modern vehicle air con machines will dose everything automatically. You can't remove the refrigerant and leave the oils behind so the machine does it all for you. Hab air con I've no idea what it is or does.
 
dunnah01 said:
For cab Aircon the garage will just connect the machine to high/low pressure lines and then turn it on, the machine does the rest. First part is to evacuate all remaining refrigerant to a safe cylinder, second part will pressure test system, then last part will refill with new refrigerant and gloppy oil stuff. No human intervention is possible unless it fails at some point.
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I'm not familiar with the automatic machines... How does it get the oil out then?
 
Richard and Ann said:
I'm not familiar with the automatic machines... How does it get the oil out then?
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It has to come out with any remaining refrigerant as it is against the law to release air con gas to atmosphere.

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dunnah01 said:
It has to come out with any remaining refrigerant as it is against the law to release air con gas to atmosphere.
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But how does the machine extract the oil if it's just on the suction and discharge service ports? The oil will mostly be in the compressor sump ?

Of course it's illegal to release refrigerant to the atmosphere "blasting off" as we used to call it 30+ years ago ?
 
The oils are mixed with the refrigerant. There is no compressor sump in normal vehicle systems
 
TeeMyob said:
30 years plus experience

run regularly
Spray with enviro coil or similar
Change pollen and cab filters
Check condenser for stone chips

18 years old Audi with climate control that automatically switches on a/c each time engine is started, recharged once at 17 years old.
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+1 - although not sure what enviro coil or cab filters are. Any failure I've seen is condenser stone, broken pipe or just old age wasteage of gas
 
Whether or not to run AC systems "to keep the seals lubed" is not provable either way, I've googled it and talked to other engineers, some believe in it, some don't.

Me? I don't, if a system leaks (usually from compressor shaft seal) it requires repairing.

Edit :Leak from condenser stone chip or rot is also quite popular ?

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dunnah01 said:
+1 - although not sure what enviro coil or cab filters are. Any failure I've seen is condenser stone, broken pipe or just old age wasteage of gas
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some cars ha e internal cab filters.
High end cars have charcoal filters
Envirocoil is a brand of evaporator cleaner
 
Richard and Ann said:
Whether or not to run AC systems "to keep the seals lubed" is not provable either way, I've googled it and talked to other engineers, some believe in it, some don't.

Me? I don't, if a system leaks (usually from compressor shaft seal) it requires repairing.

Edit :Leak from condenser stone chip or rot is also quite popular ?
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from experience, cars that do not automatically deviate to a/c when engine restarted (compared to manual systems). Rarely need recharging.
 
TeeMyob said:
from experience, cars that do not automatically deviate to a/c when engine restarted (compared to manual systems). Rarely need recharging.
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Somebody once told me R134a molecules are in long thin chains and once one gets into an escape route it drags all the others out with it. How true it is I don't know but maybe running the engine would break the chain? But the escape route shouldn't be there in the first place if the system was in tact.
 
R134a definitely is peculiar stuff, I used to work on Nottinghamshire coop systems so got used to a lot of the fridges peculiarities . Sometimes they would leak out refrigerant in a few weeks and could I hell as like find the leak, so I'd recharge it and never hear from it again ? odd stuff.
 
Richard and Ann said:
Somebody once told me R134a molecules are in long thin chains and once one gets into an escape route it drags all the others out with it. How true it is I don't know but maybe running the engine would break the chain? But the escape route shouldn't be there in the first place if the system was in tact.
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The molecules of R134a are definitely smaller than R12 which is why the liner on flexible ac hoses is different for different refrigerants but I don't believe they have chain form. If there's a leak it comes out whatever as you say.

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