Coroded Compressor Suction Line

rioan28 · Apr 1, 2016

Hello all,
I am new to the hvac world and would like an opinion on how you might solve this problem.
I have a customer with an Manitowoc QM30A ice machine who lost all its refrigerant through a pinhole in the corroded suction line right at the compressor.
The compressor still works so I was thinking about trying to braze on top of that pinhole to cover it up and also braze all around but I don't know if the brazing with Stay-Silv 15 will stick to that corroded surface. I have use a brush to clean it as much as possible.
The other option would be to cut the compressor's suction line closer to the base, where I still have good metal and braze in a new line there, but not sure how to that would affect the compressor.
I have included two pictures showing the problem.

Any advice would be greatly appreciated.

Thank you,
Rob

ga-hvac-tech · Apr 1, 2016

BAD brazing...

Not particularly corrosion.

I would try replacing that section.

Be SURE to pull a thorough vacuum.

Good luck...

Pictures of your repair please... grin!

kamersoutdoor · Apr 1, 2016

Try to unsweat it, and see what you got

pecmsg · Apr 1, 2016

Please put a small magnet on the bad section and see if it sticks.

craig1 · Apr 1, 2016

The compressor stubs are steel plated with copper. It looks like someone at the factory overheated it and burned off the copper plating

To fix that you will need to get it very clean with a wire wheel or brush, use flux, and 45% brazing rod.

rioan28 · Apr 1, 2016

craig1 said:
The compressor stubs are steel plated with copper. It looks like someone at the factory overheated it and burned off the copper plating

To fix that you will need to get it very clean with a wire wheel or brush, use flux, and 45% brazing rod.

Thank you guys for your help.
Craig, do you think it would be a better idea to cut the compressor suction stub closer to the input, where I still have it copper plated and try to braze a new line there, or should I try to braze on top of it with %45 silv? BTW i tried using a wire wheel to clean it, and the pictures show how it still looks like after cleaning.
About the brazing rod, I haven't used any 45%silv yet, only 15%, is the 45% a must?

Again, thank you very much for your help.

pecmsg · Apr 1, 2016

You need to find out what material it is then decide what solder.

joejax · Apr 1, 2016

45% is a whole other ballgame, material has to be dead clean and flux is a must.

craig1 · Apr 1, 2016

You could try cutting it back to the painted area and then cleaning off the paint and brazing to the copper underneath

itsiceman · Apr 1, 2016

ga-hvac-tech said:
BAD brazing...

Not particularly corrosion.

I would try replacing that section.

Be SURE to pull a thorough vacuum.

Good luck...

Pictures of your repair please... grin!

It's corrosion from the insulation holding water on the steel.
I'd go over the top and cut the insulation away from that area.
Found that a couple of times.

itsiceman · Apr 1, 2016

That's a tough one for a new guy
Good luck

joejax · Apr 1, 2016

itsiceman said:
It's corrosion from the insulation holding water on the steel.
I'd go over the top and cut the insulation away from that area.
Found that a couple of times.

And don't you love the old steel king valves, too?

Bazooka Joe · Apr 1, 2016

IMO, Cut closer to compressor, being careful to remove paint to the copper and staybrite, using reducing coupling or something similar. Less chance of peeling the thin copper plating off of the steel if using braze or silver

2sac · Apr 1, 2016

Looks to me like it was replaced at some point in time and someone coupled the joint and brazed over the entire mess

rioan28 · Apr 2, 2016

Thank you very much to everyone for your professional help.
I will un-braze the connection and see what I will find. I am very tempted to cut down the compressor stub pipe to the point where it still has the copper plating and then use stay bright 8 to braze a new line since it is the low pressure line. Please let me know if this is a bad idea.
I will be taking pictures along the process and will post them.
First I will have to take the ice-maker apart since I have only couple of inches around the compressor.

Again, thank you all very much for your help

yaytech · Apr 2, 2016

i would cut closer to the compressor, cut that whole bad section out, find a coupling to fit the comp stub to pipe size and use 45 percent, and as stated CLEAN AND FLUX...

yaytech · Apr 2, 2016

that section of pipe ain't gonna get better...

The_Sale · Apr 2, 2016

You could just replace that little fella. But I'd paint it up with a stick of 56FC. Make it real ugly.

rioan28 · Apr 12, 2016

Does anyone know what kind of oil I should use to compensate for the oil lost through the leak? There was a 3" oil spot right under the leak. It uses 134A refrigerant.

Thank you for your time.

fridg · Apr 12, 2016

This is from using flux on a steel to copper connection , when using flux you should always clean your flux off & paint the brazed section to stop the air reacting with it. As you know 2 dissimilar metals & a liquid can create an electrolytic solution like a capacitor.

We always painted this type of weld in our manufacturing plant for this very reason to stop pitting.

Coroded Compressor Suction Line

rioan28

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