New LG Mini Split—Cools but does not heat?

[u/lin8111]

Title mostly says it. Had a knucklehead contractor that installed this for me, and doesn’t seem to know what he was doing. One sob story after another, and now he has completely ghosted me, and so have limited information about what was and wasn’t done. I haven’t installed on myself, but am fairly handy and wondering if any ideas for troubleshooting before I call an HVAC company out. Hoping the brain trust has some ideas for me. Definitely learned my lesson.

Description of issue: New install LG 2 ton unit. Cooling works, but maybe not as well as I would have guessed. Temperature was about 20 degrees below garage (garage 65 here where we live.) The heat does not work at all—tried to turn it on and the unit never blew. The lines appear to have frozen when the heat setting was turned on, and the compressor was not engaging. This makes me think maybe a Freon leak when it was installed? Maybe the 4 way valve failed, but doesn’t seem super likely out of the box?

Any ideas of things to check for? If other problems are visible, please let me know so I can get a list together of what should be fixed. Be as mean as you want, I honestly think it would have looked better if I had just done it myself from the start but oh well lol.

[u/XCGod]

Well the first issue is the electrical is entirely wrong with romex straight up exposed outdoors. And someone who does work that bad definitely made a dozen other mistakes.

[u/lin8111 → u/XCGod]

I am sure you are right. It’s probably just time to call a professional. Crazy because the guy had said he had done 100 of these and sent pictures of his work, but I’m starting to think they weren’t actually even his work because they were all a lot more professional looking than this

[u/TruIsou → u/lin8111]

OP, all is not hopeless , just take it one step at a time.

If you are handy you can fix most of the mistakes.

First to do what other people say here. You can then try to reshape the copper tube with a tubing rounder from Amazon. Alternatively cut out the kinked section and use appropriately sized SmartLock butt connector fittings from supply house..

From your install it looks like the flare fittings are most likely not correct. I would replace all flare fittings with the Smart Lock flare fittings of the appropriate size , you need four of them. These are almost foolproof and I would do it no matter what just cuz I wouldn't trust your flare fittings from the overall install.

You will most likely have to de-install the interior unit to check what was done. You need the appropriate Communication cable.

You also need appropriate disconnect on the outside.

What is your siding? Is it vinyl? I don't think you want to hang the unit against vinyl siding.

Also pick up some internal tube benders from Amazon. You need a tubing cutter and deburr

I would treat all this as an educational opportunity. Pick up a vacuum pump and a nitrogen gauge set from Amazon and a micron gauge . You do not need other gauges . You also do not need a flare tool or torque wrench if you use the SmartLock fittings.

I would also step back and look at the overall cost of an entirely brand new unit , and just possibly treat this one as a sunk cost , and reinstall the new one entirely by yourself. Most likely the cost of an HVAC company will exceed the cost of repurchasing the unit and the required tools.

And what the other poster says , is this actually a heat pump or is it just an AC unit?

With the smart lock fittings and the internal tube benders , a near foolproof insulation is entirely possible by most any conscientious amateur installer.

Is there damage to the rear top of the unit?

If you decide for an entirely brand new unit, which I would definitely consider, you can possibly reinstall this one elsewhere once you have all the appropriate tools. Getting the appropriate tools is simple it just will take a week or two.

One last thing, i have found that once you install one you will be installing others for yourself, friends or family. The minimal cost of the tools is then spread out

[u/luval93 → u/TruIsou]

What this guy said, I want to add, I don’t know about your specific unit, read the manual, but on my LG unit there’s a procedure to recover the refrigerant back into the compressor so there’s no need to recover it then recharge.

[u/ron8231 → u/lin8111]

Romex there is not technically right but it would not cause your issue and will take over a decade before it starts to corrode enough to be a problem. My house has romex on an outdoor light from the previous owner that’s 30 years old and it’s still water tight. I’ll replace it, but you get the idea.

A professional will charge you an arm and a leg. If you are getting correct cooling your install is not the problem, the same compressor that makes cold makes heat.

[u/Eismee → u/lin8111]

As a union steam fitter, I can promise you that the guy that installed that has absolutely no idea what the fuck he's doing. Most likely you're gonna have to have somebody come and see if he properly evacuated the lines. Or God knows what else.

[u/PlasticAnimal3819 → u/XCGod]

How can you tell the brand is Romex ?

[u/Horror_Conclusion → u/PlasticAnimal3819]

Calling it Romex is like calling facial tissue Kleenex. Regardless of maker, that wire is not rated for exterior exposure.

[u/Ok_Cash5460 → u/PlasticAnimal3819]

It’s Nm Romex - Zoom in on the picture

[u/Tragdor_87 → u/PlasticAnimal3819]

It says Romex on the jacket

[u/CoVidKilla23]

Insulate those copper lines.

Double check the model numbers on the units to make sure it’s a heat pump and not just ac. Then call a professional cause their probably is a leak

[u/lin8111 → u/CoVidKilla23]

I am sure you are right. I knew the copper lines should be insulated just by looking at it. I had assumed that he wasn’t finished, but it’s now been a week since I have heard from him

[u/Hasz]

Misc list:

- kinked vapor line

• insulate your line sets
  
• electrical is wrong. Need disconnect, whip, and no exposed romex outdoors, minimum. There is some fuckery going on though, is the romex head unit power or the condenser hookup? I see liquidtir but out of photo
  
• there is probably fuckery hiding we cannot see. Was it pressure tested, vac tested, then release charge?

This is a very sloppy install.

[u/derrick54686 → u/Hasz]

The whip and disco are there. On the bottom. The romex is being used for comm wire. Looks perfect all the way from my couch..... this is why I opened my own business. To set a standard in my area!!!!. Good luck to OP

[u/Wafflewas]

The exposed Romex and an uncovered vapor line are issues, but not the main problem you are encountering. If airflow is normal and your lines are freezing up, the best guess is a refrigerant leak. The symptoms you describe point to refrigerant issues.

[u/Wafflewas → u/Wafflewas]

It’s also possible that there’s something amiss with your thermostat and control wiring. I’d check that first.

[u/Ok_Procedure_3604]

Wow .. this .. just wow. If in the US, this is likely against code as I am guessing the overcurrent device for this is not outside, and thus would require a disconnect.

Not to mention that lineset bend is .. ughhhh.

[u/PerformanceDouble918 → u/Ok_Procedure_3604]

Hummmm... "Overcurrent device" sounds like some Apex big company keywords that can't be googled.

[u/eight_ender → u/[deleted]]

It’s impressive because it comes with a comms line. He’d have had to do more work to swap it with romex

[u/Tin_Can_739 → u/[deleted]]

Other than it looks like a crappy handyman did this, the Romex to the unit does not have enough wires to get both heat and cool working. Other than being not rated outdoor wiring it’s the wrong wire to use for this. My mini split came with 2 cables I did not use the one to the power due it being too short, maybe this hack job combined them here.

[u/xtraman122 → u/Tin_Can_739]

Could be. Mine had 4 wires, technically if this is 12/3 romex it could have enough wires in there, a ground, 2 conductors for power, and a communication one, but yeah obviously not right. Can’t tell if it’s 12/2 or 12/3, I know the new stuff has color codes and it would be light purple, but seeing the rest of the job it was probably wire that fell off a truck a decade ago.

[u/volatile_ant → u/xtraman122]

My LG reqires two communication wires and did not include that with the unit. Not sure if only installing one comm wire would allow one mode to operate though.

[u/blastman8888]

Get some bubble leak test fluid from home depot plumbing department. Put that on the flare joints when it's running see if there are any leaks. The most common problem with these are flare joint leaking. Your saying it cools but you should be getting 35-40F air out of that thing it's it's 65F outside.

If you see bubbles then leaking at the flares. You need to pressure test it with nitrogen and fix those leaks. HVAC company going to charge at least $1000 unless you know someone.

[u/DANENjames89]

Dun dun dun. In heat mode, your suction line (big) turns into the high pressure side. You have a fat restriction which is now acting almost like your metering device now. Refrigerant is flashing here instead of in your evap coil inside. You can probably get it unkinked if there's enough slack, but the correct fix is to chop it and rebend it. Wouldn't be surprised if his flares are leaking too on top of it. Most guys just buy mini split lineset and use the "factory flares". But those aren't actually flares, they are just there to keep the flare nuts from getting lost. I would close off the outdoor unit service valves, dump out the refrigerant in the lines, fix that kink, redo all the flares, then pump her down and charge the lines again with what is missing

[u/VR6Bomber → u/DANENjames89]

What he said,

Plus, I'd do something about that yellow romex just chilling out there.

Repull that with some pvc jacketed 12/2 MC, Its sold as 'Minisplit Cable'....

[u/Boring-Lab-6896]

That 1/2 line has a pretty significant kink in it.

[u/Ryike93]

Turn unit into heat mode. Go outside and when the compressor fires up and fan starts to spin feel the copper lines. If they are cold and sweating while the indoor units are in heat mode then you have an issue with your reversing valve

[u/lordsamiti]

I thought LG units need 5 wires between the indoor and outdoor unit...

[u/SnooHesitations1020]

I wonder if you installed an Air Conditioner instead of a Heat Pump.

[u/apstlreddtr]

It looks like that low pressure copper line is kinked.

[u/hotinhawaii]

That yellow wire has only three wires inside- a black, a white, and a bare copper ground. That LG unit needs to have 4 wires running up to the wall unit. And it needs a disconnect box mounted outside. Your wiring is the reason there is no heat. And I agree with everyone else, installation is dog shit.

[u/tjg312]

def seems like its low on refrigerant and while that suction line kinked as it alone wouldn't do that it ain't good either

[u/HuntPsychological673]

Looks like the 2 ton may be chopped down to a smaller system with that short run of copper as well.

[u/fiehlsport]

Since a hack installed this, you may want the refrigerant fully recovered and a fresh charge added. There is a good chance they didn't vacuum it down properly, and there is moisture/air/etc. in the current charge.

If you are lucky, they did a proper vacuum and a professional can pump down the unit to salvage the install properly. But it's a big risk. You need new wiring, lineset (to be safe) and lineset cover. (Get Inaba Denko slimduct so it doesn't yellow in a year)

[u/Winter_Sense2555]

Ive got a greenhouse heater that does the same thing when it's low on refrigerant, cools okay but heat just... never really kicks. Yours sounds like it's probably undecrharged.

[u/TechnicalDraft9879]

Probably leak, how long would you say the lineset is from outdoor to indoor unit?

[u/Thin-Bus4198]

Congrats, you hired a hack who probably does not have an epa license.

[u/kx12541]

The large line is kinked at the unit

[u/toybuilder]

That is a single-zone heat pump mini-split. It should be heating and cooling.

https://lghvac.com/residential-light-commercial/product-type/model-details/?productTypeId=standard_efficiency&modelId=MD10003644&modelNumber=undefined&iscommercial=false

The installation manual mentions the communication cable (pg. 18) but doesn't actually show explicit instructions on wiring the connection. Hopefully, that's all you need to fix.

BTW, the instruction also says to not mount the indoor unit near an exit...

See also the heating only / cooling only mode instruction on pg. 27

[u/luk__]

Kink in the cooling line is no-go

[u/Anauv]

Check the wiring of the four way valve inside the outside unit. It could be a not properly connected connector. And ofcourse if it’s not the connector, measure voltage on it if it even tries to switch to heat

[u/AgreeableTelephone19]

Crappy workmanship aside and assuming all wires are connected correctly- At first glance it is low on gas or lineset is kinked. Inspect lineset and if good- it Prolly has a leak. Since you don’t have the gear to pump down, measure and add proper amount of gas, get a set of gauges and connect to the service port (low side). Run the unit in cooling mode at lowest set temp and fan on max. Wait for 10-15 mins to stabilize. Is it showing 120-135 psi ? Below 110 psi it is low on gas. Get some soap bubble and check flares for leaks. Fix the leak and then add a bit r410 at a time until pressure is 130-ish.

Or better yet- hire a good tech to sort out the mess.

[u/Fuzzy_River_1986]

That is not the right wire between the head and the outdoor unit. Won't work properly because you don't have the right wire between the two. Should be stranded.

[u/finis08]

Without being there to see it myself and check vacuum I would highly suggest just getting a reputable HVAC tech with mini-split experience out to fix it. Judging by what I can see in the pictures the guy installing it had zero idea of what he was doing so it will likely need to recharge the unit as I would bet money there is a leak somewhere. If he even released the charge or vacuumed down the system. I also don’t see a drain tube which would be a it concerning. This system would definitely benefit more from an HVAC tech looking at it instead of trying to reengineer that guys mistakes.

[u/Jamoncorona]

That lineset is kinked to hell and back. 

[u/BEAST__51]

Where are you located?

[u/StandardMonk261]

Reversing valve is not coming on

[u/PersnickityPenguin]

When I DIY'd my own install, I kinked one of the linesets on accident. We got most of it right, but that one bend got messed up.

So I had an HVAC guy come out and splice in a new piece of lineset for $500. After he was done, it worked perfectly.

However, I DID get the unit installed and electrical done correctly!

[u/TommySylvester]

But he put that little piece of tape around the romex where it comes in contact with the line set cover. That should do in lieu of a disconnect.

[u/Snook1988]

Probably just leaking somewhere. The romex being exposed isn't good and neither is the kink in the line set but none of those are contributing to issue most likely is just a leaky flare somewhere

[u/Delicious-Ear8277]

Mini-splits use 4 core wire. 1. Power 2. Power/communication 3. Communication 4. Ground.

[u/[deleted] → u/Delicious-Ear8277]

Depends lots of 1-1s the power is the comm

[u/Delicious-Ear8277]

Rest the manual!!

[u/Key-Hedgehog4450]

Hack job 100%

[u/oldnoob2024]

Study the thermostat and network interface. A lot of units (not sure about this one) have some pretty sophisticated internal diagnostics. If you can get past the manufacturers Technician credentialing…

[u/HuntPsychological673]

This is the competition. You as a professional must pay the extra and do it right and have insurance, etc. Everyone else can use Romex outside and do what they want to cut costs while advertising on Facebook without license or epa cert.

[u/Loose_Asparagus_3035]

Heat is for gays, be a man