With regard to more information for Ray, i can only give you more background on the fault, as i have had previousl engineers go to this site and carry out works as per Diakin Technical. The original complaint is the same, fault E4 occours intermittantly. Going back to the begining it all seems to start from a leak on caplillary line, which was repaired and recharged accordingly. Several calls to state the system was not working, on arrival the cutomer had reset the system and got it back working, making it difficult for us to pin point the fault. It then went out on code F3 after several checks Daikin suggested a fault with the internal valves of the compressor and the discharge pipe sensor. Unfortunately i was not convinced and went for the cheaper option of the discharge sensor. We then managed to find out that the receptionist was arriving in the morning and feeling cold tunred it on full heating then once warm tuned it down to Cooling to the original setting, this was an ongoing problem until she was told not to touch the controllers.
Again the fault re-occoured so we opted for the compressor replacment as per daikins advice. They then suggested a Tattle Tail to be installed on the Lp switch which we did and left for some time, this did not give us any further information except it didnt blow.
As suggested previously i think (bearing in mind i am not a A/c engineer) but as frank suggests LOGIC it must be either a PCB or Lp switch fault.
This is based on Discussions with Ray, but what do i know------------Not alot i can tell you
Obvioulsy changing the compressor and discharge pipe sensor on Daikins recommendations has proved that it wasn't that.
Thanks for all the advise being given i am very appreciataive of all the help.
Cheers
Cooling-Guru