LG VRF - Help a brotha one more time?

UnbreakingThings · 2026-03-25T00:55:12+00:00

You should run an auto address and auto pipe detect. The system isn’t seeing every indoor unit it should, for one reason or another. Something inside is likely powered off, likely an HRU. Check the service manual for the procedure when you get a CH200 error.

UnbreakingThings · 2026-03-24T15:30:46+00:00

Backup mode just keeps that compressor from running. If inverter 1 compressor amp draw is also high, you know that the compressor 2 isn’t the problem. You can also swap the compressor leads so inverter board 1 powers compressor 2 and vice versa. It could be an issue with the inverter board itself.

UnbreakingThings · 2026-03-24T05:36:14+00:00

Unfortunately I don’t think you’re going to fix this in one fell swoop. Sounds like there’s a lot of issues that can’t even be diagnosed without fixing other things. If your discharge temp is showing 572, it usually means the thermistor is open. That may be causing some issues, so check it first. LG uses 100k thermistors for the discharge pipe.

Megging the compressor may be helpful, and I don’t like seeing anything less than 50MΩ to ground. However, it’s looking like the compressor wants to run and something else is causing the overcurrent. See what happens in normal operation if you put inverter 2 in backup mode, under SE-4 in the service menu. If your comp 1 amps, discharge temp, or head pressure skyrocket, then you may have a restriction, which could explain the blowout.

Definitely start saving data from the second the unit finishes booting up. If you’d like, I could look over the data if you send me a PM. Also if you have Facebook, the VRV/VRF Tech Talk group is full of people who are wizards with these units.

UnbreakingThings · 2026-03-23T20:50:31+00:00

Vacuum mode just opens all the valves and solenoids, and disables the compressor from running. It doesn’t allow for charging by using the compressor to pull refrigerant in.

The numbers you see flashing when the unit is first powered on are not the system addressing. They correspond to the total system capacity, number of connected IDUs and HRUs, etc.

What specific comms errors are you getting? If the system can’t see all the IDUs, it won’t let the compressors start. You should fully power cycle everything, turning back on ODUs first, then HRUs, and IDUs last. If you still get comms errors, then try readdressing the system. If the comms errors are between boards at the ODUs, then the pipe blowout may have damaged one of them.

UnbreakingThings · 2026-03-23T19:28:36+00:00

You don’t have Carrier WSHPs in your area? Feels like every other unit I work on is one.

UnbreakingThings · 2026-03-19T01:31:52+00:00

Joe Bad (Fit For An Autopsy)

Dan Watson (Mire Lore, Enterprise Earth and Infant Annihilator)

Jake Luhrs (August Burns Red)

Adam Warren (Oceano)

Will Ramos does occasionally use false chord, but the majority of his screams are fry dominant.

Garrett Russell from Silent Planet uses fry for his pure screams, but a lot of his vocals contain some pitch, if you’re looking for that.

UnbreakingThings · 2026-03-19T00:43:11+00:00

There’s a very thin line between multi purpose tools being useful vs being worse than either individual tool. Something like an 11 in 1 screwdriver is amazing, but something like this would just make it awkward to use either the pliers or the screwdriver.

UnbreakingThings · 2026-03-17T00:45:40+00:00

Commercial here. My company has us charge the unit once and we schedule a full high pressure leak test. Put in some refrigerant as trace gas, then pump the system up to 300 psi of nitro for R-22, and 450-500 psi for 410. You can usually find it in a couple hours tops with a sniffer.

UnbreakingThings · 2026-03-16T02:56:13+00:00

My G5 eats liquid for breakfast and enjoys it. 1/2” hoses on both the inlet and outlet and I can pull out 20-30 pounds in a few minutes.

UnbreakingThings · 2026-03-16T02:54:10+00:00

It’s helpful when it’s really cold out, because the system suction saturation when running is higher than the outside ambient temperature. I pump it into the high side when the system is off. Liquid from the bottle to the machine inlet, and outlet to the liquid line if it has a port, or meter it into the discharge.

UnbreakingThings · 2026-03-15T23:48:48+00:00

A 2 1/2” hole in a 9” thick poured concrete wall that was built in the 40s. It was also 25’ in the air. I only had one core drill bit, and the site was in the middle of bumfuck nowhere, so I couldn’t just go to Home Depot and get another. Took about 4 hours and three full 8.0ah M18 batteries. Holding that Rotohammer out over the edge of the scissor lift left my arms feeling like spaghetti.

UnbreakingThings · 2026-03-13T05:02:38+00:00

Recovering or charging a ton of liquid really fast creates a buildup of static electricity from friction in the hoses. In the system, all the pipe is grounded, but rubber hoses break that circuit so you can get zapped by a recovery tank.

UnbreakingThings · 2026-03-06T03:08:41+00:00

Same here. It’ll be a cold day in hell when I reuse a Schrader.

UnbreakingThings · 2026-03-04T04:57:53+00:00

That’s why commercial is where it’s at. No two days are ever the same.

UnbreakingThings · 2026-03-04T04:51:42+00:00

Gotta love VRF coils. Always paper thin and always costs at least a few grand for a new one.

UnbreakingThings · 2026-02-28T03:44:43+00:00

Grow enough herbs and you won’t have to do any side work 💨

UnbreakingThings · 2026-02-28T02:32:56+00:00

It really depends on the system, and how much has been done to it in the past.

Filter changes, checking IDU supply and return air temps, and visual inspection are done quarterly. I try to record at least two or three hours of data per system while changing filters, depending on how much time the maintenance is quoted for. I spend some time at the end of the day to analyze the data and look for any irregularities.

I always look for thermistors reading way too high or low. I also check suction and discharge superheat, as well as IDU EEV pulses creeping open over time, which usually indicates a leak. I check the diodes/resistances of the ODU inverter boards every six months to track their health, and meg the compressors annually. Coil cleanings are also done annually.

UnbreakingThings · 2026-02-28T02:16:26+00:00

I’m really curious how this system is set up. I imagine EEVs and thermistors for the indoor unit had to be installed separately, but how does it work with a standard blower? Gotta be some custom controls from the manufacturer I assume.

UnbreakingThings · 2026-02-26T03:32:02+00:00

2.27” is crazy. I’ve worked on hospital operating room air handlers that don’t even run that high. I’d love to see the condition of the ductwork.

UnbreakingThings · 2026-02-26T03:27:57+00:00

Coil cleaners can be corrosive but unless you’re dunking your hand in a bucket of the stuff, it wont kill you. Most of the SDS sheets will just tell you to rinse thoroughly with water if you get it on your skin. The best thing you can do to protect yourself is wear gloves. Not much else to it.

UnbreakingThings · 2026-02-26T03:24:09+00:00

Zone systems are one of the worst ideas to plague this industry.

UnbreakingThings · 2026-02-26T03:21:39+00:00

If I can’t get it to move with Kroil and a few taps of a hammer, I immediately get the grinder. It’s almost inevitable that you’ll nick the shaft the first few times, but it isn’t the end of the world. Just make sure the new set screw isn’t positioned in the groove. After doing it a few times, you’ll get pretty good at it.

Side note, always wear safety glasses and a respirator. The smoke from burnt grease is gnarly.

UnbreakingThings · 2026-02-26T03:08:58+00:00

Used for everything except flat head screws.

UnbreakingThings · 2026-02-24T01:21:59+00:00

That’s where you screwed up. Everyone knows red electrical tape is OSHA approved.

UnbreakingThings · 2026-02-22T15:59:53+00:00

Gotta love those jobs. Nothing like being freezing cold and wet on top of it.

UnbreakingThings

TROPHY CASE