LG LMXC23746S Fridge not cooling

[6010fd12]

[Vance R]

Look good 

[6010fd12]

Ok so I setup my nitro on the low side with both valves off but didnt feel it coming out of the high side. I thought because it was coming out of the evap but looking back now I think my 3 way was on the wrong setting. Anyways, I brazed the suction side first and everything went well and at the cap I was very conservative with my braze and after I was done I could hear squealing and bubbling. The nitro was escaping out of the braze I made through a pin hole. I reheated my braze while it was still hot just enough to dab a little bit of silv onto it to cover the hole and now I see no hole and heat no nitro escaping out of the evap. Should I still be concerned or is it all good?

[6010fd12]

Sorry. It deleted my message when I posted the pic so I head to retype it. Hate mobile.

[Vance R]

1 hour ago, 6010fd12 said:

Should I still be concerned or is it all good?

Yes. When your done with the system you can pressurize whole system to lowside test pressure. Check all your joint with bubbles, touchup as needed.

[6010fd12]

3 minutes ago, Vance R said:

Yes. When your done with the system you can pressurize whole system to lowside test pressure. Check all your joint with bubbles, touchup as needed.

Gotcha. So now I assume I need to replace the filter drier. I hate to ask but could you run me through the the steps of how I can remove and install a new one? The new one I ordered already has a service valve attached to it. 

[Vance R]

Kinda like the evap - decide if you want to unsolder or cut tubing.  The highside tubing is steel and you'll need to use 45% silver and flux. The 3-way valve tubing is copper so you can use 15% silphos.  Protect the yoder tubing at the cabinet and the 3-way valve from heat just like the copper to aluminum transition on the evap.  it you are concerned about the drier you can use heat trap paste or wet towel on body of drier. I prefer to remove the valve core on the drier to prevent pressure build up. There should be an arrow on drier body to indicate refrigerant flow direction.  Fit the drier in place, flux the steel side and braze in place.  I try to have torch tip on the compressor side pointing out . This way you don't have to worry about the flame tail burn things in the machine compartment. Some guys don't like torch pointing at their face so stay alittle off to the side of flame. If you point the torch into the machine compartment the compressor will take a fair amount of heat, but the tags burn. 

PS: do not over heat the steel tubing, it is cheap recycled garbage. It will glaze and make it hard to get a good joint. Watch your flux really close. As you heat the flux it will dry out as moisture evaporates, then as it start to melt it will look wet. When it starts to look wet you are about correct temp you can back the torch away alittle to prevent overheating. No bright red glowing! Tap the solder on to the joint to see if it melts.  Bend a 1"  leg into your solder to aid in not using too much solder in the joint. 

BTW - the evap job is way harder to solder because of the tight space and plastic all around.

Edited June 14, 2020 by Vance R
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[6010fd12]

I dont have any flux. I will have to go out and buy some. Will this work? Also I assume I will need to run nitro from the low side to the drier. How do I open up the 3 way to let nitro flow from low to high?

[6010fd12]

Also I forgot to ask, when everthing is done and I get to the part where I add refrigerant will this work? I know my system is a r143a that takes 4.76oz but I read online that you cant mix automotive and appliance refrigerant due to oil differences. I know the can says for mobile use but I'm pretty sure this is pure refrigerant without any oil or dye additives. I still want to make sure just to be on the safe side.

[Vance R]

Couldn't get either link to work. Homing the 3-way valve there is 2 ways. 1. plug in unit for 6 seconds and unplug, you can feel the valve vibrate. 2. plug in and push the daig button once on the main board and wait a minute and unplug. If you have already done this and haven't plugged the refrig the valve will stay in last position.  As long as your r134 has no dye or oil or leak stop it will be ok.  The flux i like stay-silv for brazing by harris. 

[6010fd12]

And both of those options would put it in fridge mode correct? When I'm going to pull a vacuum on the system how do I access the freezer evap?

Also the links didn't work for me either for some reason, here they are.

https://www.menards.com/main/tools/torches-soldering-tools/stay-silv-flux-6-5-oz/sswf7pop/p-1470101956864.htm

https://www.homedepot.com/p/12-fl-oz-Canister-Refrigerant-R134A/302287969

[Vance R]

Those links work, both look good.

By homing the 3-way valve you are putting it in the position where it is open both evaps at the same time. This position allow you to recover, vacuum and charge the system. The evaps are in parallel and most of the time the 3-way feed just one evap at a time. LG will feed both evaps on initial on start up then it will give preference to the refrig evap. Also in the force mode step 1 it will drive the compressor to full speed and turn on all fans and feed both evaps for about 5 minutes.

[6010fd12]

Are you sure the left side of the drier is steel? It looks like copper

[6010fd12]

Just tested it and the line is not metallic on both sides

[6010fd12]

Ment magnetic sorry. I dont know how to edit my comments.

[6010fd12]

The braze on the very far left is where the yoder comes out of the cabin is magnetic but nothing else from that braze all the way to the 3 way is magnetic. So I'm thinking maybe cut the tubing coming out of the cabin close to the drier that way I can just use regular 15% silphos on the copper tube for both sides.

[Vance R]

Opps was clear enough, but you figured it out. The tubing is steel and that where 45% silver and flux is needed for copper to steel joint. The copper to copper the 15% silphos will work. Nice idea to cut next to the drier to have a copper to copper joint.

 

Just more info. The condenser and yoder loop are both steel tubing.  The compressor stubs are also steel, but usually are clad with a layer of copper. 

Edited June 15, 2020 by Vance R
Add info.

[6010fd12]

Gotcha so just to confirm the tubing coming from the cabin is steel and the tubing from drier is copper while the tubing coming from the 3 way is also steel? Is this correct or do I have it mixed up?

[Vance R]

3-way valve is copper.

[6010fd12]

The drier is copper too? and the pipe from the cabin is steel then correct.

[Vance R]

Yes

[6010fd12]

Ok thank you. So then I should be able to get away with brazing this pipe that I cut off from the old drier into the new one with just regular 15% no flux or anything. 

Sorry if I keep asking these redundant questions I just tried to do that yesterday and I don't know If the settings on my mapp were wrong or maybe the flame had no where to escape while I was brazing(i am using a custom shield on my torch) but my rod did not want to melt/flow and I ended up with this. I ended up carefully grinding the drier pipe off with a dremel to not damage the interior pipe. I'm going to attempt it again tonight with maybe a different angle where the flame can exit without being trapped so close in between the drier and cabin. Good thing I bought 2 driers.

[6010fd12]

Ok got it I think. Idk what went wrong last time.

So now all I have to do it purge the system, pressurize it, vacuum it, then fill the system correct?

[Vance R]

Nice braze joints and yes.

[ECtoFix]

Brazing with MAPP is a challenge since they changed the formula several years ago.  Too much torch time on the lines can damage other components.

Looks like you did good.