R22 & R404a Multiplex Systems

[Rudi]

Good Day

I need Information on Multiplex Systems, One of my Clients has 3 Multiplex systems and I have found a couple of problems on 2 of the systems

Both Systems oil return pipe is leaking oil and needs to be changed however there is no shut of valve and I fear I might loose a lot of refrigerant if not done properly,

one of the systems has a sweat on TXV Danfoss, that has a broken cap tube and needs to be replaced, but both of the evaporators located in the butchery prep area are not working on of which has the broken txv. its just very strange that when you put in such an expensive system ( rarely seen in South Africa) that there is no shut off valves to isolate the evap's. It would make the job much easier if you were able to isolate a certain part and work on it.

my main question is, how do I replace this TXV, how do I pump System down, do the work and purge the system again? I need detailed information on Multiplex systems

Hope Somebody would be able to assist

Thanks In Advance

[mattym]

Could you not pump down at receiver tank and do the work that way and you would still be able to change tev