Hi,
Regarding my last posting as to my air con phoned garage to ask how much gas they had refilled the system with and was told they had put 1000g of 134a in and was told that the reason why the air con was,nt very effective in the rear was due to the fact that some of my valves were on the way out ,I did mention that i was under the impression that the system should take 1450g but was told that 134a gas was heavier than R12 and putting 1450g of 134a would over pressurize the system ,so needles to say i did,nt get any joy . Iwas wondering about having the system looked at by another air con firm and topping up if possible also does anyone think that the shortfall in gas at the moment is the reason for the air con in the rear and the cool box not being very effective any comments on the problem would be appreciated
regards
Mal

- (#2022) Mal, 30 Jun 05 13:21

Think about what you have written. Is 1450g of lead heavier than 1450g of water? 1450g is 1450g! We are talking weight not volume.

Valves on the way out? Do they leak or don't they?

I'm not saying there isn't anything wrong with your system but I do know that when my aircon is getting ready for a regas the first thing to fail is the coolbox (and I've had mine recharged twice now). It should run with only 1000g in it but it won't be efficient.

I would recommend you take it somewhere else and explain the symptoms and what has/hasn't been done. You can't trust someone who comes out with responses like that.

- (#2022) Ian Dunse (Derbs), 1 Jul 05 01:19

From the Archives:

" ... 20% less as R134a gas has ... larger volume for the same weight as R12. HTH regards Rob Drinkwater, 12 May 02"

Several other postings discuss this in Ace Answers > Aircon.

- (#2022) Dave Mason (Sussex), 1 Jul 05 02:31

Sorry to have to correct you here Ian, 1450g of lead takes a lot less room that 1450g of feathers, same principle with R12 & R134, one has a smaller & heavier molecular structure then the other. The smaller molecules of R134 also present another problem, I.e. you need a replacement control valve on each evaporator to reach best efficiency, additionally R134 is simply not as capable as R12 as a refrigerant, i.e. it doesn't have the same specific heat capacity so cannot carry heat away from the evaporator as well as R12.

Simple rule of thumb works here, if it should be 1450g, take away 15-20% for R134a, which is 1160-1235g.

HTH Rob.

- (#2022) Rob Drinkwater, 1 Jul 05 13:09

hi folks what it is iam thinking really hard bout getting a mpv for my nxt mode of transport i have never owned a mpv before i got my eye set on two but i can only choose one of course the townace or the previa i got about 1200 pounds i got four kids only young if a townace which ones best for economy space all round ability thanks any help in this matter would be greatful

- (#2022) david thorley, 10 Jul 05 17:41