Hi guys, just joined the forum all though have been reading it for a few months,i have a question or two on repairs to domestic R600a units.

just some background I'm an independent engineer that does some contract work to the large Italian Manufacture, been doing the electrical for years but iv been doing refrigeration for about 2 years with them and there is an few issues that are bugging me

We seem to see a lot of R600a units with no or low gas symptoms, we vent then evacuate and hold for 1 minute to check for leaks, they always generally pass the hold on this test, short of acut pipe they normally do hold vac, on the system pipework there is a anti condensation fed that runs around the front where the doors are to prevent sweating, this is fed directly from the high side before the condenser.

Recently we have been told that if we have a unit where there is no signs of leaks on the vac hold test we should cut and bypass the anti condensation circuit, this is due to that pipework being steel and are known to rust through on the lower corners, annoyingly will always pass a vac test though, its a simple 5 minute job as the feed and return are all next to each other.

now i'm not a fan of this as its 90% the customer will be calling back complaining after a month when they see water around the door however my main concern is charge weight, obviously R600 has very low charge levels, most domestics are around 40g, i was also taught that r600 has a charge accuracy of 1g so it must be correct,

The question no one can seem to answer is should we not be reducing the charge when bypassing this anti condensation curcuit ? it a large length of pipe work, its got to be equal to the condenser in length.

its bad enough with these systems that you go in, diagnose no or little gas, do a full test system and not really find an issue, do a full system repair and walk away with fingers crossed it wont recall a week later.

Sorry for the long post but wanted to try and explain fully and its really bugging me now

thanks in advance