Hi,

My air con has been working ok for abit but not very cold.... Recently its started to make a hissing type noise....

Does this mean my air con is totaly knackered or do i just need a re-gas....???

Dan

 

Sounds like the system is short on gas. When the system is running as it should fully charged with gas. The gas is compresed above the ambiant temp then passes thought the condenser where it is condsed back in to a sub cooled liquid which passes thought the expansion device in to evaporater to be boiled of in to a gas again back to the compressor. This is the basic refrigertion curcit with out going in to much more detail. when you lose gas you loss that cycle and the expansion device only gets gas. Hissing is what you get when you Pass refrigeration gas at 130psig thought a tiny hole in expansion device.

 

Mine makes that noise also, not really a big problem.

Run the A/C then look at the A/C glass view hole if you can see something in the sight glass then your A/C will need a recharged.