Holding a vacuum is the direct opposite of the way a/c works, which is under pressure.
DIY Aircon top up.
- Thread starter Mottie
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Holding a vacuum is the direct opposite of the way a/c works, which is under pressure.
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I never turn my a/c off - it's a climate system, so I just leave it to get on with it. It is almost essential in my car, which quickly steams up in winter, to dry the air.
I’m sure I’ve read in the owners manuals of new cars we’ve owned that says the a/c must be used for at least 30 minutes per month, even in winter. Some cars have the a/c on by default and you have to turn it off. When you do that, the switch remains illuminated to let you know it’s off just like the traction control or start/stop systems. I found that out to my embarrassment when I once returned a Merc A class back to the Alicante hire desk soon after picking it up and having a rant about the a/c that wasn’t working. 
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That one worked for me. A 15 second burst and you’ll be sorted.
It's interesting to compare that with the automated drain, measure, vacuum, refill, new oil, test
£60 at places like kwikfit.
and if it doesn't work, no charge.
I'm told that the new automated machines remove the risk of clumsy or unskilled work or corner-cutting.
I ask for the printout so I can check how much oil and gas has been lost - if a lot I know I have a slow leak.
my BiL is an aircon and refrigeration engineer in Oz, mostly on yachts, and tells me that the vacuum is essential to remove water vapour traces.
£60 at places like kwikfit.
and if it doesn't work, no charge.
I'm told that the new automated machines remove the risk of clumsy or unskilled work or corner-cutting.
I ask for the printout so I can check how much oil and gas has been lost - if a lot I know I have a slow leak.
my BiL is an aircon and refrigeration engineer in Oz, mostly on yachts, and tells me that the vacuum is essential to remove water vapour traces.
perhaps it's recirculating.
I've seen people make that mistake in the Rockies, where temps can be -40 but the outside air is bone dry.
That is more than I paid for a mobile a/c guy to come to me and top mine up.
Yeah, but it's cheap and quick and it gets rid of the water vapour!
Why not a pressure test first, followed by a vacuum? (I don't know, just curious)
I've used one of those before. It should work, if there's nothing else wrong with your system, other than a lack of gas. However, it's only the same price as getting someone to do it for you at KwikFit, using a proper machine! (And then, only if you get your £10 deposit back). Of course, you still get your charging valve and gauge assembly to go with it, which you can use in future. I got one too, but the rubber seal in the bit that screws to the bottle got attacked by the stuff in the bottle and turned to jelly! Quite what that says for the stuff in the bottle and your car's seals, I'm not sure. Hopefully, the seal in the gun is just ordinary nitrile rubber so that's why it melted. I replaced mine with a green o-ring, suitable for R134a and I'll see how that fares!
That's the downside of running the aircon all the time. Your heater box is always full of condensation. Eventually, it'll start to smell damp and cave-like. Most systems (whether they're switched on or not) don't actually work when the temperature gets below about 5 degrees C. They nearly all have a means of shutting off power to the compressor if the evaporator core gets close to freezing, because then all the condensation on the fins turns to ice and no air can flow through the evaporator. If you drive around with your aircon on, at outside temperatures around freezing, the compressor won't be running anyway.
I know there's not much in it but I get the hose and gauge and hopefully it will do more than one top up, and I'll find out for myself once and for all whether they work.
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It turns out my car has the older R134 gas in it instead.
I took it down to the local Ford garage I got it from (It's a KA+) and the owner looked at the spinny thingies and said the AC clutch is not engaging so no wonder its only delivering warm air.
Likely due to a loss of gas.
So it's booked in for an FOC regas (seeing as I only got it from them a couple of months ago) so YAY! for me.
The wifes needs it also, but she never claimed under the warranty so I'll try find somewhere cheaper for it. (The garage over the road from work gives work a discount so Ill try there first)
Regarding what has been said, about refilling - not to fill to x pressure but until it provides cold air - when filling the engine is turned off so how can you tell? keep turning it on and off while adding a little more? lols
I took it down to the local Ford garage I got it from (It's a KA+) and the owner looked at the spinny thingies and said the AC clutch is not engaging so no wonder its only delivering warm air.
Likely due to a loss of gas.
So it's booked in for an FOC regas (seeing as I only got it from them a couple of months ago) so YAY! for me.
The wifes needs it also, but she never claimed under the warranty so I'll try find somewhere cheaper for it. (The garage over the road from work gives work a discount so Ill try there first)
Regarding what has been said, about refilling - not to fill to x pressure but until it provides cold air - when filling the engine is turned off so how can you tell? keep turning it on and off while adding a little more? lols
With the DIY cans, you do it with the engine running.
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