Guys my Aircon has been hit and miss the last 2 summers...  It works then it doesn't work somebody mentioned previously about a possible valve sticking on the air con unit 

 

Can anybody let me what the valve is or part number 

1st off have it regassed

 

£40 ish

 

 

Theres a pressure valve that stops the pump running if the gas is low

 

 

the A/C man can check for leaks

Got regassed last year no leaks will have a look at pressure valve