Hi all

I have just put in my first MHI split unit, which went well overall, but I have a few questions which I'm not going to find in the documentation, so thought I'd keep them all together in one place. Apologies if they are a bit random or daft.

1) In the evacuation process I had my digital gauge inline inbetween the manifold low-side and service valve, and the pump in to the centre port of the manifold. I had to see positive pressure when releasing the gas before I could remove my gauge, and lost some gas in the meantime. What is the best configuration and process to use when evacuating? (idiots guide). Should I have my gauge tapped into my manifold instead just using one port on it (ie not 'inline')?

2) Related to the above... I was seeing 300 microns with the pump running, but isolate the pump and that quickly rose (within 1 minute) to 1000 where it settled and didn't rise. I evacuated for another 3 hours and this was still the same, so figured it was fine, as it was a lengthy pipe run. I was careful to keep the caps on the pipes when installing and it pressure tested fine. Is this normal behaviour, or have I been too hasty in releasing the gas?

3) I know it will change according to many factors, but roughly what pressure should I be seeing on my manifold low-side when all the gas is released into the system? Just as a peace-of-mind check.

4) I couldn't find imperial sized insulation. For 1/4" (6.35mm) and 3/8" (9.52mm) copper I ordered 6mm and 10mm armaflex. The 6mm fits great, but the 10mm is pretty loose on the pipe. A bit concerned it will not be effective !?

5) Insulation again - how far up into the indoor unit do you insulate with armaflex? My indoor unit came with both pipes held loosely together in some sort of foam. I installed it as-was and then stripped what I could off the pipework that was external, and replaced with armaflex up to the hole in the wall, but the internal pipe is still just loose in the original stuff.

6) Last one - I did have to re-do the flare a few times to get it to seal. Eventually I just nipped it up a bit extra on the torque wrench, and this worked. Especially on the 1/4". I have the proper eccentric 410a tool and oiled the outside of the flare, but when the tool completes a flare it leaves 'ridges' in the copper at 180 and 360 degrees, where it snaps off when it is done. Could this be causing a problem? Or do you generally just need an extra turn on the wrench (18 & 42 nm I think it was).

Cheers

Reptile