Leaky mini split maybe NCG

ChrisJ

I'm helping someone that has a bunch of mini splits he installed him self a few years ago. As far as I know, they weren't pre-charged linesets....

The system leaks, and I'm going to assume has been full of NCG because he didn't know what a vacuum pump was.

This being the case, after I fix the leaks (I assume bad flares) what can I do to improve this and get him by for a while? Can I add a drier to these anywhere? Is there an acid neutralizer that can be added? They run 410A.

It would be great if I can just fix the leaks, pull a vacuum and refill but I've got a bad feeling that's not going to be the case.

ChrisJ

@GW @ratio

Any thoughts?
I realize the right thing to do is to tear it all out and start over, but I'm trying to help him out the best I can.

ratio

If it were me, I'd just fix the leak, vac it down, & recharge it. Let it run a while & then check for acid & water; treat if necessary. If there's significant damage you don't want to spend too much effort on it, if it's good enough to run, well, there it is.

Check what flavor of oil it has in it. IIRC Mitsubishi is using some synthetic that doesn't react with water, maybe this one is too.

JUGHNE

Does anyone ever add a bi-flow filter drier in the "small" liquid? line of a minisplit.

If no, what is the reason?

ChrisJ

JUGHNE said:

Does anyone ever add a bi-flow filter drier in the "small" liquid? line of a minisplit.

If no, what is the reason?

I thought about that, but it almost seemed like using a suction line drier would be less intrusive.

That "liquid line" is after the EEV, so it's on the boiling side of the system, no? I don't know how that would behave.

EBEBRATT-Ed

@JUGHNE
most mini's use the liquid line as part of the metering device at least they used to. Could always put one in the suction line. Heat pumps more difficult

ratio

Most|all of the systems I've worked on (Mitsubishi, Carrier, Daikin) (mini splits & VRF both) don't have filter-dryers at all. A fine mesh screen is all they use, fine enough to get plugged by the oxidation if you don't purge with N₂.

GW

sorry i don't have any experience with what you're asking (buggered up mini install)- if you vac and hold under 500, i think that's the best you'll do or can hope for. never ever heard of a dryer on a mini.