Hello, I was offered a position to do warranty work for an LG and Samsung authorized partner. I’ve been a tech since April of ‘24, but never did much with the sealed system portions of fridges beyond diagnosing bad compressors or restrictions.
I understand how the system works, like what the compressor, condenser, evaporator, dryer, Yoder loop and capillary lines do. Depending on my knowledge I’ll be able to keep the job or get let go, which I would hate as this would be life changing for me. The steady pay check with volume beats gambling my income between repairs and service calls.
I’d like to ask if you always fill the system with nitrogen after replacing a component, or do you use your vacuum pump? The way they were doing it during training was remove components, replace components, draw vacuum, refill system, then test for leaks at the lokrings.
They work with r134a and r600. I was told those have different operating pressures with the inverter compressors. I should expect to see anywhere between 5 to -5 on inverters with r600a on the low side, and between 55-70psi on the high side.
I wasn’t given pressures for r134a, but from my experience, between 0-5psi on the low.
My questions are-
1. What would be the proper procedure for replacing sealed system components?
-They would just cut and vent the refrigerant, sand the connections, then slap the lokrings on. AFAIK you’re supposed to recover it.
2. How can you diagnose a restriction without looking at the evap coils?
-The 2 techs I was training with knew without looking at the coils.
3. What pressures should I expect to see on the system using an inverter compressor depending on the refrigerant used?
4. Do you always use nitrogen through the system, or is it just to get rid of a restriction/pressure test?
4a- Do you always pressure test when replacing components or not?
5. Any other things I need to ask or know for this?
Any advice related to this would really help. Wednesday I’m supposed to speak with the head of the company and depending on how that goes I’m let go or kept to do hass training and then start work with them
That’s exactly what I thought and what I asked the trainers. It was OJT, so I shadowed them for work. They said it wasn’t the case. They’d cut the lines of the unit off and move forwards with the replacement
Regarding nitrogen, I dont do any SS work yet, but Ive heard that you run nitrogen when brazing to keep the system from developing some kind of a contaminating oxide that creates a restriction.
I would hope they would send you to a technical school for two weeks to get your 608. The manufacturers want to believe that with R600 out in the world, there's no need to have a 608 - " just use LokRing." Nonsense. Class will teach you how to work safely, braze pipe, recover refrigerant, and troubleshoot properly.
Now, knowing that 80-90% of LG calls will be dead compressors does not foreclose the idea of troubleshooting. They have been known to blow garbage into the condenser...
No sir, it was do you know enough to work with us? The 2 techs I shadowed don’t have certs but knew how to do the work. LG only uses lokring anyways, but I’ve had a small amount of experience brazing actually. The fact they didn’t send me to any tech school is why I’m asking here actually
Also, all compressor replacements include a dryer and condenser replacement when done for LG.
With R134 coming up at $1500 a tank, and the serious health risks to you and customer's pets, I would not be cavalier about working with the stuff. Recover whenever possible. With R600, pull a vacuum after venting and flush with nitrogen if you can.
The only thing I hate more than LokRing is to scrape lacquer off the Korean's systems. Brazing is more reliable in my book.
Jesus it’s that expensive? They provide the refrigerant for us but lord that’s pricey. That’s even more reason to recover it and not just vent it.
Thank you for the advice on r600. You would pull the vacuum after replacing components and then flush out the crap with nitrogen? Or would you flush first, then replace components and finally vacuum before refilling?
I also agree with what you say about brazing. Lokring just feels like the easy way out
I vacuum immediately after venting R600, and flush if I think there is a restriction - then I will braze. Not going to risk touching off residual gas. Use a RobinAir kit to hook your manifold to either process stub and it goes quickly.
That’s exactly how I was thinking of the process. And I was actually going to ask about that. They had a kit that allowed them to connect the manifold to the capillary lines and also the Yoder loop. I saw a robin air kit for it but it was only the top part, they had it connected to a quick connect at the bottom where you would connect the gauges at. It looked like this picture
I carry their 12458 kit in my sealed system gear. R600 jobs start with me slicing the end off the process tube, hooking up a RobinAir adapter and vacuuming it down.
Yes, I was originally trained by pressures but now I do by weight. Everyone, even the trainers however, said lokring was crap long term. How come you think it’s better?
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u/zipchuck1 23d ago
Failing to recover can lead to a fine directly you to. And a fine to the business you are operating under. That was part of your ODP training