RLS refrigerant valves

mthmlf84

I'm installing a new LG multi max system at my house, two outdoor compressors each going into one distributor branch box and serving 3 (the other one 4) indoor units.

Since it's so many units, I decided to spend the extra money for ball valves in case one unit needs servicing down the road so I don't have to recover the whole refrigerant, etc.

When I first installed, the system passed the 550psig standing pressure test for 24 hours, held 420 vacuum for another 24.

Upon commissioning the system, I got an error message because the total capacity of the indoor units I installed exceeded the the capacity of the outdoor unit by more than 130%, so I had to unplug the communication wires for a few units and run the system that way for a while. It worked beautifully, really great.

Then I had to cut my system in half so to speak and add a second compressor, pump down and recover the refrigerant, reroute the linesets (one outdoor unit for upstairs, one for downstairs) and close the ball valves to lock the refrigerant in. I have them right outside the distributor box on the liquid and gas lines.

back to square one with the standing pressure test. The half of the valves are leaking from the nut underneath the handle. one of them is now leaking from the shraeder (it wasnt before). replaced the shrader, tightened the nuts.
To make a long story short I've been unable to successfully conduct a standing pressure test and have been at it for like 10 days. Found some areas where the torque was just a little under on the fittings and tightened them up to spec but I'm still leaking 0.1 psi per 5 minutes at 550 psi, and i've let it go down to 508 over a few days, accounting for the changes in temperature, it's leaking. I can't prove they're the culprit, but I don't trust those valves! They feel junky, I don't understand the design really, turning them on and off feels like taking a huge risk. Anybody have any tips on how to make sure they don't leak? shraders are tight, caps are on, nut above is tight.

otherwise here's what I've done:

- charge 410a into system until I reach 10psi, then nitrogen up to 550, sniff test with electronic leak detector on everything including the coils, inconclusive

- soap bubbles on every nut at 550psi nitrogen in the system, valve, shrader, RLS crimp (my linesets are crimped, RLS zoomlock, from the branch box it's direct but from the outdoor unit there's a few 90 deg elbows to get into the house cleanly). Can't see any bubbles anywhere after 3 times very thoroughly.

-checked torque on every nut, tightened

- eliminated all fittings except one hose and one digital pressure meter I'm measuring at the valve in my attic (where the temperature is more stable throughout the day

I'm losing my mind. Tempted to eliminate the valves altogether.

EBEBRATT-Ed

It could be your refrigerant hoses as well, your gage manifold or any of the zoom lock fittings.

It's a small leak for sure. A refrigerant tester will be needed most likely. The bubbles may not pick up a small leak

mattmia2

Are there caps that go over those ball valves? I would install them for the pressure test, the caps are to seal the stem completely. I would also use flare caps for the access fittings rather than those o ring caps, that o ring can leak a little bit.

Ironman

What model leak detector are you using?

mthmlf84

Ironman said:

What model leak detector are you using?

I'm using this, which is pretty low end chinese-made equipment, didn't serve me too well. I intentionally released a mixture of 410a and nitrogen to see if it would pickup and it's very irregular. In the end it did lead me to the general area where my leak was (the nut on one of the ball valves). I tightened all of the nuts on the valves and suddenly the leaking stopped! after days of confusion.

The initial vacuum went well, down to 290 microns very quickly, 2 minutes, everything was very dry from days of pressure testing I imagine. held 530 solidly. broke it with nitrogen and let the pump run for an hour while running an errand to pull a deep vacuum. came back to a pump that had overheated and stopped, probably sucked some oil and humid air in, I feel like it's going to need a lot of purging, but there's hope!

Still don't trust those valves and wondering if the uncertainty they bring defeats the purpose of having them as part of the system in the first place. Would almost feel safer without them. Anybody ever use them happily?

mattmia2

I would not trust valves that do not have flare caps that go over the valve stems and over the access valves to hold the refrigerant in the system long term.

Ironman

I don’t think the valves are faulty, but as @mattmia2 said, the caps need to be on them.

Also: don’t take the caps off or attempt to operate the valves while they’re under a vacuum.

mthmlf84

I just wanted to update and say I managed to get the leak, I guess I misunderstood how the valves worked initially and have found a way to make them do what they're supposed to do. Couldn't find any instructions anywhere. I tightened the nuts on top completely, then loosen them just a bit so it's possible to operate the valve (with the brass cover and locking nut not pictured above. Then tighten the securing nut to hold it all in place. Still not convinced about the design. I wonder why it's not more like a conventional ball valve!

PC7060

The high vacuum load requirement is what drives the design.  I’m sure standard ball would fail under those conditions.