Re: DIY Air Conditioning Recharge
I know this thread is old but summer is coming again.
I don't agree with most of the posts for topping up your own A/C.
Crit71 and Felix are the only ones with the right idea.
The Halfords pressure gauges are next to useless, If the A/C has enough gas to run the compressor then the pressure in the low side (the one you are measuring) is regulated to approx 2 bar regardless of if the system has too much or not enough gas! Not only that but the pressure in the high side (condenser and smaller pipes) is totally dependent on the aimbient air temp.
Incidently, the static (i.e. switched off) pressure can be anywhere between 3 and 6 bar (ish) again depending on ambient temp.
The ONLY way to accurately fill the system is to use a charging station which weighs the ammount of gas that goes in, i.e drain the system, vacuum for at least 20 mins then re-charge.
If the system doesn't have enough your fuel comsumption will increase because the A/C has to work harder to get the cooling effect, worst case is the compressor will overheat and sieze due to lack of oil (carried around the system by the gas)!
Too much gas and, again, the compressor has to work too hard (too much pressure) high fuel consumption and lack of cooling. Overheated compressor and possible siezing.
Admittitly these are extremes but I've seen it all before.
There's no subsitute for a professional service/repair, trick is finding someone you trust to do it properly!