I noticed my air con was blowing hot air so yesterday I took it to a "specialist" who pressure tested and re-gassed it but it was still not getting cold.

He then plugged it into his computer which I got charged for and the result was there is no electrical faults. His diagnosis was there may be a block in the system somewhere and he would have to replace bit by bit to find the problem which would be very expensive! There must be a easier and cheaper way to find the problem? The compressor works - the pressure gauge on his machine was going too high then the compressor cuts out?