Last update:

08/03/2005

 

Recharging the AC

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Recharging the Air Conditioning

A brief spell of very hot weather found the Climate Control struggling to cope with very high ambient temperatures and when I checked I found with some surprise that it had been four years since the last regas. This was twice as long as recommended by Pete C on the AirCon page - so the system needed a check over. I tested the Vent Temperatures, and found that in an ambient of 23 C the temperature at the vent was only 12 C at 1500 RPM.

I tried to contact the guy I had used before, but his franchise had ceased trading, so it was back to a search. In a field where there are many cowboys I needed a guy whose advice could be relied on. A search revealed Aircon Direct, with an advice page here and they specifically mention some points which indicated to me that they knew what they were talking about. These included:

bulletNoisy compressor "You need a new compressor, guv."
bulletRecharge, not a 'top up'
bulletDrawing the system into deep vacuum to remove moisture

I rang for an appointment for a home visit.

In the meantime, there was a job I had been meaning to see to - upgrading the sticker for the AC capacities from the 740g to 1000 grams of gas. I collected this from my Ford Main Dealer (cost 1.49) so that the car was ready for the aircon guy - without the sticker he wouldn't put the new recommended amount of gas into the system: the 740g fill is virtually standard for all Fords, with the possible exception of the Ka.

I left the car in the garage in case it rained, and Mark, the son of the proprietor, duly arrived. I helped him bundle the heavy machine out of his van into the garage - normally, on the roadside the machine stays where it is, but it was threatening to rain and I wanted us to stay dry - and then it was plugged in.

Aircon Direct use the latest, computer controlled equipment to recover the gas, clean it and then recharge the system. Below, the Sun MRC334 machine. On the right, a view of the 134a gas bottle. This stands on scales which the machine uses to weigh off the correct amount of gas.

 

 

The machine is plugged into the mains and the gas connections are made, one each to the pressure line and to the receiver/dryer.

Mark now dials in the procedure he wants the machine to adopt. The length of time taken to draw the system down into vacuum, the length of time to stay in vacuum and the amount of gas with which to recharge is all programmed in. Then Mark starts it, and we can relax. Time for tea, two sugars.

The low and high pressure hoses from the air lines on the car terminate in this gas block, with a dial for each. The centre connection is to the machine, which draws out the gas back into a recuperator. Below, the bottle separator on the front of the machine. In my case, there was so little gas left that it didn't show here.

In the middle of the procedure, Mark measures out the extra refrigerant oil which Ford states is necessary for the new gas level, 60 ml. He takes off the gas line from the block and the vacuum sucks it up as soon as he opens the tap:

Then the machine continues, and the gas is withdrawn from the tank together with the 210 grams recovered from the system, and you can watch the measurement on the machine as the gas is sucked into the vacuum. It stops at 1000 grams.

Excellent. We finish our tea and let the system settle for a while, then we run the engine and watch my digital thermo through the windscreen. Remember, previously the vent temperature was 12 C at 1500 RPM.

Without touching the throttle, we watch the temperature fall. Within seconds it's gone lower than I've ever seen it, then still further. I managed a shot here,

2.6 C - and this at idle. The AC was cycling, and the next cycle showed the vent temperature stop at 2.1 C, while the ambient in the garage was quite warm because of the engine, 23 C. At this temperature a vent temp of 3.8 would have been at the low end of specification, and only at 1500 RPM, while we had not touched the accelerator at all!

Next, Mark checked the system for leaks, both visually and with a detector. The magic Wand is very sensitive and a slow scan at all the joins and the condenser revealed nothing - but we didn't really expect any. If there had been a leak after four years there wouldn't have been any gas left at all.

Aircon Direct charge a standard 60 for a recharge, plus VAT. They can replace parts as required and point out that they can supply a part for fitting much cheaper than a Main Dealer.

For older systems, like Granadas (I know some members also own them as well), there is a substitute for the now-banned R12 refrigerant. This is called RS24, and Aircon Direct undertake this work. They can also convert an R12 system to 134a, but this is a bit more involved, needing the replacement of the receiver drier and some seals which may not be compatible - but you can contact them for good advice.

In this field it's good to find some good, straight guys who do a proper job. If you need your car recharged and you live in the Southeast you should bear them in mind. For other areas, John is compiling a list of proper technicians who you can call upon - check out the site for this info.

Thanks to Mark

Aircon Direct 01474 832941

EricR

 

 

 

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