multi zone split whistles, doesn't heat

wmgeorge · February 2022

And what’s to the right of the small line? A cap tube metering device. As such that makes the small line the suction line in cooling!

No its not really the true low side until it gets to the indoor coil, the 1/4 inch line acts as a partial restriction until it gets to that coil and the compressor low side pressure can help it expand. The LEV also acts as a metering device in the cooling mode, regardless if that line has frost you have an issue. In the heating mode the LEV is wide open.

When do you see AC evaporator coils with frost?

Regardless All my flared fittings I treated as I said above.

In the mean time the poor OP has his Thread hijacked again.

mthmlf84 · February 2022

hey no I like reading this stuff and trying to understand.
they sell this, it's expensive, it's basically loctite on a copper washer supposed to seal your flare, I'm tempted to try it as extra insurance while the system has zero pressure.
https://www.supplyhouse.com/Rectorseal-97220-3-8-Flaretite-Seals-Box-of-10

still leak testing my system, got all the big leaks plus a very subtle tiny one that was hard to notice. 3 of the IDU are in my attic and there's lots of crawling involved, I'm glad I wired lights up there before the insulation guys came. system holds 100psi of nitrogren no problem for 2 hours without moving at all but when I try to get to 300 and 500 pressures as per the manual, the cheapo valve core removers I'm using as access fittings start leaking! I don't have any other way of getting a solid connection to the 5/16 ports so I'll have to wait for the Appions I ordered to arrive. Annoying.

There's a bit of whistling sound coming from either the metering devince or the accumulator when I charge with nitrogen. Charging 2 ports at the same time, opening and closing the gauges slowly to give it time to take the gas. it's not a leak, maybe just the nitro going through a smaller component. I wonder if it's normal.

Also got some POE oil because I feel like i'll need to top up after extended leak testing an empty system? have not looked into that yet.

wmgeorge · February 2022

Would not worry about the oil. Interesting those "things" you posted for flare fittings have the same stuff I suggested.... Blue Locktite. I have no experience with what you posted on the flare "things" perhaps others do.

Frankly and repeating myself yet again, those flare fittings have no place on high pressure R410a, they might be fine on the R22 systems these first came out with years ago. Should be either silver brazed or Sil Phos.

ratio · February 2022

mthmlf84 said:
they sell this, it's expensive, it's basically loctite on a copper washer supposed to seal your flare, I'm tempted to try it as extra insurance while the system has zero pressure.
https://www.supplyhouse.com/Rectorseal-97220-3-8-Flaretite-Seals-Box-of-10

I've used these on a problem flare before. Be aware, you've still got to properly torque the connection, they'll compress & leak if you don't.

Also got some POE oil because I feel like i'll need to top up after extended leak testing an empty system? have not looked into that yet.

First, if no oil came out it's all still in there. Second, no guarantee it's POE. At least one brand (Mitsubishi) uses PVE oil, which is not hygroscopic (see e.g. https://www.idemitsu.com/en/business/lube/pve/daphne.html).

mthmlf84 · February 2022

put in nylog blue everywhere, put flare tite on all the flares except the main 3/4 and 3/8 which never leaked and I think were done right. torqued everything to spec, leak bubble test the whole thing at 100 psi. It's 100psi completely for hours, doesn't move at all. Waiting for the better quality access fittings and will do the high pressure test. If that works, I'll the lines, triple evacuate, and then I need to charge it properly, might need extra advice when I get there.

then I'll find out if the one time it tried to heat for 8 hours almost without any refrigerant damaged something or not?

wmgeorge · February 2022

If you have a good vacuum pump and a Micron gauge pull a good deep vacuum and warm the compressor with a heat gun / lamp or something to 100-150 degrees and keep the pump running. If you can hold 300-500 for an hour or so chances are you have the moisture out.

Be aware most gauge hoses will not be good for pulling a deep vacuum, we used copper tube but maybe the hoses are better now?

vtfarmer · February 2022

wmgeorge said:
Well if that's the case get an real education in H&C not just on here or You Tube and go in business yourself! I have tried and tried to get local younger folks interested in the trade, I had perhaps 230 in my two year full time class over the 12 years I was teaching. All but one or two had jobs waiting when they left including 2 or 3 girls.
Added, we used the Delmar textbook for most of it, I will try to find a link to Amazon.

This is the textbook we used, and gee whiz the price has gone up! Get your EPA Cert and this book study as you go and learn the correct way to do stuff. Yes this is an expensive trade to get into, or in my case back into!! I started out in 1961 in the USAF as a Air Craft Electrician and when I got out took classes to become a electrician and that really helped a lot when I decided to switch to HVAC and took classes for that also.

https://www.amazon.com/Refrigeration-Conditioning-Technology-Bill-Whitman/dp/1401837654/ref=sr_1_15?crid=OS54JLVGJPLE&keywords=delmar+heating+air+conditioning+book&qid=1645390072&sprefix=delmar+heating+air+conditioning+book,aps,93&sr=8-15

I have that book, it's awesome!! Very comprehensive HVACR material and it even covers (a little bit) of non-heat pump heating topics, too. Paid I think $12 for it used (looks like amazon still has used copies for sale), definitely worth the money and I should have thought to suggest buying it in my original reply.

To the OP: the EPA class I took at a community college had a lot more actual training than just passing the test, which is why I suggested it, but it looks like between the certification you took, the advice you're getting here, and some new tools you're getting much closer to solving your problem. Good luck and this will be so much more rewarding when it's up and running.

mthmlf84 · February 2022

vtfarmer said:

wmgeorge said:
Good luck and this will be so much more rewarding when it's up and running.
If that thing ever works I can't imagine the feeling I'll get, haven't had normal heat all winter, it's a been a journey, my wife's been really patient, etc. Really appreciate you guys spitballing and giving advice. I found the book for 11 bucks used! The EPA cert isn't much but it was nice to learn something in a more structured way with the threat of a test, as opposed to picking up bits of info on youtube at will.

George what does warming the compressor do? I understand it's useful when you're recovering refrigerant but I don't understand this use of it.

SuperTech · February 2022

Warming the compressor helps release refrigerant from the oil in the compressor. Without doing this when it's cold outside it will be almost impossible to pull a proper deep vacuum.

The vacuum hoses available today help make the process easier. Copper tubing to the pump works great but isn't always practical. It's a best practice to avoid evacuating through a charging manifold. 1/2" or 3/4" dedicated vacuum hoses from the pump to the core removers is the way to go. Put a little Nylog on the hose connections for best results.

ayetchvacker · February 2022

pecmsg said:

wmgeorge said:

The metering device is in the outdoor section. The small line is low pressure liquid and frosts.
Never. To help you understand I have attached the flow diagram, The Liquid does not frost its warm or cool unless its a charge issue. The Stop valves are the ones on the outside unit.

And what’s to the right of the small line? A cap tube metering device. As such that makes the small line the suction line in cooling!

The LEV is the metering device in this diagram. You are correct tho that in cooling mode on any system with the metering device in the outdoor unit (mini split) both lines are suction only in cooling mode, although specifically the small line in cooling mode is an expansion line since it’s carrying saturated refrigerant. In heating mode the small line is the liquid line. I know you know this already. Just hoping to clarify so OP doesn’t get confused. Also since his specific unit used a branch box the lines may actually be liquid/suction.

Cheers

wmgeorge · February 2022

Not sure of the quality of the hoses today for deep vacuum work, I would guess they are way better. I retired in 2007 so I had to purchase a new name brand gauge set for my Mini split job.
When I worked on cascade ultra cold freezers - 130 F I used copper tubing to hold the deep vacuum required.

ayetchvacker · February 2022

mthmlf84 said:

the rol air one looks nice! I nitrogen purged a little bit and am now leak testing like I should have done the first time. started with 50 psi because I know there's a leak, lost 20 psi of nitrogen over just an hour. found a few leaks already, most of which I corrected. mostly on 1/4 lines, a lot of them weren't torqued to spec at all! way looser than they were supposed to be, 6 ft lbs ish instead of 14-19, ridiculous. lots of them fixed. continuing. starting to have hope that the main problem (aside from stupidity) was just loose flare fittings and that I lost all my refrigerant through that before even turning the system on the first time. that would be really nice.

You’re making great progress! Eagerly waiting to hear the results of your pressure test!

You mentioned you didn’t see any oil at the flare connections. If the system leaked while it wasn’t operating you probably won’t see any oil. The oil mixes while the compressor is operating. Typically I find oil, sometimes a lot, in leak on R410a systems but not every time. Don’t forget to soap the flares while under pressure and check carefully for bubbles.

wmgeorge · February 2022

What He

said /\ I was assuming that he OP was soaping the flare... but any way be sure to wash off that soap solution with hot water as left on it can cause corrosion.

GW · February 2022

You pulled the charge? You didn't weigh what you took out? Without knowing 100% sure you had the controller/settings/wiring nailed?

You said your vac was good. Unless you had a gusher, the system should have started and made some heat for a little while. IF you had a gusher, you would not have been able to pull any vac numbers (and held them) . Sure would be a bummer if you yanked the charge for nothing

wmgeorge · February 2022

You pulled the charge? You didn't weigh what you took out? Without knowing 100% sure you had the controller/settings/wiring nailed? GW you need to keep up he said the system was dry.

mthmlf84 · May 2022

hey I just wanted to come back here and say thank you very much for the help and advice.

I was trying to feed 7 units with one 60K outdoor unit and the total amount of indoor unit BTU ended up being over the 130% outdoor capacity allowed so we had to split the system in half over two compressors, one upstairs, one for downstairs, run lines accordingly, etc. The one downstairs with 4 units is the one happily running for over a month, upstairs system still doesn't pass the standing pressure test at 550, it's a very very very slow leak probably coming from one of the RLS valves, I hope anyways.

If someone is going through an epic install of a larger LG multi max system I might be able to offer some advice. Definitely still not a pro but I learned a few things about the system. We're running mostly low static ducted units with dry contacts going into ecobee thermostats. It works great.

Anyways thank you again.

multi zone split whistles, doesn't heat

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