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Old Amana Frig with oxide on main copper line

Dave Savanna

Premium Member
Joined
Aug 1, 2020
Messages
5
Location
California
Model Number
TV18R3W
Brand
Amana
Age
More than 10 years
Owned this since new. Frig wasn't cooling well only to 40° a while back, but the freezer cooled fine. On a whim I changed the condensor fan & it now cools the frig perfectly. Old fan must of been weak from age, but old fan ran & sounded fine? It blew into frig, but new one blows harder
My question today is the lower copper line from the compressor up to the freezer has oxide along it. Can I clean this off or should it be left alone? Is this from condensation on line or someting else. It's been there for many many years when I clean back there annually & the frig works perfect & always has.
Any suggestions would be appreciated
 

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Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
2,840
Location
Canada
Dave Savanna said:
Can I clean this off
Yes. Steel wool could be used. No need to go crazy cleaning it off though. However, the cause needs to be found and corrected (like when it frosts right back to the compressor).


Dave Savanna said:
Is this from condensation on line.

Yes, but it shouldn't.

That is suction line. Above it (under the insulation) is the "heat exchanger". A capillary tube (skinny tubing) is welded onto the side of that suction line to creat a heat exchange between the two lines. Sometimes the weld between them fails and those lines separate and no longer produce the heat exchange it's designed to, causing frost to accumulate on it instead. Each time the compressor stops running, that frost melts and drips down to cause the oxidation. It could even frost all the way back to the compressor which is very bad.

I suggest someone open that insulation (probably best to replace it afterward) and inspect the lines underneath. Let us know their condition and/or post some pictures of it. If it's separated, it can be repaired reasonably well.

If separated, it shouldn't be left that way. It will hamper proper cooling ability and in extreme cases it can damage the compressor (like when it frosts all the way back to the compressor).


Dan O.
 
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Dave Savanna

Premium Member
Joined
Aug 1, 2020
Messages
5
Location
California
Appreciate your help
There's no moisture at all currently on the line with compressor running or afterwards? That line feels mildly cool to the touch, but not cold in any way. If you notice in pic the bottom is clean like new under that line with no old dust grime buildup like the rest of back? Probably from dripping moisture down like you mentioned.
I open the back yearly & blow it out not paying attention to much. The oxide came to my attention a few years back, but it has probably been there much longer.
If the lines are separated how would I repair them back together to work properly do their job? Also any specific type of insulation to be used when replacing or just general?
I'll attach photos when I attempt job soon for guidence
Thanks Much
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
2,840
Location
Canada
If the heat exchanger has separated, both tubing needs to be cleaned up as well as in between them. Emery cloth works best for the latter area. If you have it, a heat sink compound spread between the separate pipes (although not absolutely necessary) and then the cleaned copper lines wrapped tightly together with electrical tape or similar, from end to end wherever the original solder was.

Example Heat Exchanger
heat_exchanger.jpg

Any pipe insulation would be fine to cover it after the repair as long as it's not overly loose. If the original insulation isn't breaking down too badly, it could be reused if necessary. Perfect insulation is not absolutely critical. You can tape the insulation back together at several points along its length if necessary.


Dan O.
 
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Dan O.

Appliance Tech
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Joined
Oct 9, 2004
Messages
2,840
Location
Canada
Dave Savanna said:
If you notice in pic the bottom is clean like new under that line with no old dust grime buildup like the rest of back? Probably from dripping moisture down like you mentioned.

Looking more closely at the image, it doesn't look like that is the whole reason. The tubing closest to the compressor is above the rest of the tubing.

image.png

The moisture shouldn't have migrated to that point if just running down the heat exchanger. And I don't see any evidences from dripping directly from above. Maybe that line only frosts in the winter when the house is cooler or when it's been running for an extended period like after a large order of food?


Dan O.
 
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Dave Savanna

Premium Member
Joined
Aug 1, 2020
Messages
5
Location
California
We live in the mountains where it snows so it gets really cold here. We also usually leave for a month during the winter and turn the heater down so pipes don't freeze. Maybe that's it like you say. I cleaned the lineup easily today with vinegar and baking soda. It looked worse than it actually was but like you said shouldn't be there at all & especially by the compressor.
After your reply I guess I'll put off removing the insulation & will check back there in the winter for moisture and compare line to current pic.
Before I replaced the freezer fan on this one we bought a brand-new pricey whirlpool to replace it. Frig only got to 40 degrees after 24 hours recommended. Turn it all the way up and it finally got the 38 after 12 hours on high. They wanted to replace it & I was so disgusted I just sent it back for a refund. They sure don't make them like they used to. This old dinosaur cools from warm to temp in 2 hours. The fan is it's only lifetime repair. It also uses more electricity than the newer ones LOL
Thanks Much Appreciate
 

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Dan O.

Appliance Tech
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Joined
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Messages
2,840
Location
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Dave Savanna said:
After your reply I guess I'll put off removing the insulation & will check back there in the winter for moisture and compare line to current pic.

I wouldn't. It's not a difficult repair and if it is frosting back to the compressor as I suspect, you might be forced to go to one of these new refrigerators whether you like it or not.

Even it it's just taping the exchanger and putting the old insulation back, I'd suggest someone doing it before it leads to more problems.

JMO


Dan O.
 
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Dave Savanna

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Joined
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Messages
5
Location
California
I opened the lines up & both are attached all the way down. Compressor had just turned off & line had a bit of condensation on top 8". Bottom of insulation had some oxide dust. Going to clean line up & cover back up
 

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Dan O.

Appliance Tech
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Joined
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Messages
2,840
Location
Canada
You're right but they are also pretty oxidized too.

Has the freezer motor ever failed to blow? It failing to turn might cause the evaporator to frost up excessively and that frost migrate down the heat exchanger.


All I can suggest for now is to rap it up good and check the operation of the freezer motor. Keep checking it and the heat exchanger periodically. Hopefully you'll eventually catch what is happening to cause the oxidization.

Dan O.
 

Dave Savanna

Premium Member
Joined
Aug 1, 2020
Messages
5
Location
California
Thanks for all your help Dan
It's 26 years old & works like a champ & still looks good. We've never had any issue with it since new except recent freezer fan change when the frig wasn't getting lower than 40 & running longer. The fan was just a wild guess & I got lucky there
I'm amazed it's lasted this long & we'll keep it for whatever time is left in it. They sure don't make them like they use to.
Take Care
 
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