Hitachi airconditioning problem

[mlaauwen]

We have a problem with our airconditioner it is a Hitachi although it is an old one it works fine when it works.
Our problem when we activate the airconditioning the compressor makes a terrible noise. We had 2 times a mecanic looking at the system but none solved the problem one thought the Neutral was loose or made a bad connection and the other added 1,5 litre of oil into the system. The problem stays and comes and goes. I now found out when the noise commenses and i switch the remote control on the wall from cooling to heating and directly again to cooling it works fine and we don't have any problems for the whole day. For me it sounds like a valve which isn't working well but again I am not a specialist in airconditioning. Can anybody give me some advise? It is a Hitachi on the outside unit on the unit it says something with a UzuQ but the type isn't readable. It is a system 380V I think moreless 20 years old.

Please help

[martinw58]

sounds like a lot of oil to top up a system with
you may have a faulty 4 way valve in the out door unit

[coolarse]

20 years old, doesnt owe you anything, i think its time to put your hand in your pocket and invest in a new one

[mlaauwen]

Is it possible to replace such a valve without loosing the refrigant gas? I was already thinking about this valve because the first mecaninc said the i believe the high pressure side was very high and the filters where clean and the fans outside were working. I am going to check which valve is inside and if itreasonable to make the guess to replace it. Should it be welded hard? or would silver do?
Thanks for your help

[bill1983]

please please please don't attempt any repair yourself. Even if you feel you are reasonably competant with pipework/welding/brazing/soldering, you will probably cause at the very least, injury to anyone near the system if you don't understand the processes you are going to have to carry out. Far better to employ a reputable a/c engineer to correctly diagnose and quote for any repairs he deems necessary. it may seem cheaper to attempt the repair yourself but you will still need an engineer to recommission the system.

[kathysierra]

Hi, in my opinion you should go for a change.
Though it may be repaired but it may create problem again.There must be some parts worn out as it is too old one.
You can try air conditioning Services or AC Repair Florida ,if residing there.
Invest some bucks and be happy with new unit.
Good Luck.

[lomb]

please please please don't attempt any repair yourself. Even if you feel you are reasonably competant with pipework/welding/brazing/soldering, you will probably cause at the very least, injury to anyone near the system if you don't understand the processes you are going to have to carry out. Far better to employ a reputable a/c engineer to correctly diagnose and quote for any repairs he deems necessary. it may seem cheaper to attempt the repair yourself but you will still need an engineer to recommission the system.

Listen to this advice, the units operate at high pressures and can cause frostbite, loss of eyesight and death if something comes loose under pressure.