Strange leak. P.I.T.A. To fix

[GenesisRefrig]

Old, small grocery store. Low temp rack low on charge. Walked to store with my leak detector and it goes nuts in the walk-in freezer. Narrowed down to the evap coil that’s leaking, pulled panel on end with TXV and start checking with bubbles… no leaks. Check all joints, no leaks. Thought I heard gas escaping, but couldn’t narrow it down so I got a young employee and borrowed his ears. He says it’s coming from the fins in the back. He takes a Sharpie and circles the area for me.

I start pulling the aluminum fins out, and this is what I find.



Only this one tube, and only in this one evaperator. I’m guessing that at some point in its life, a buildup of ice caused this damage, what do you think? Anyone else ever run into this?

[GenesisRefrig]

Oh yeah… The fix

[pecmsg]

Repeated freeze ups crushed the tubing.

[R600a]

That's an odd one.

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"Is this before or after you fired the parts cannon at it?" - senior tech

[ehsx]

Repeated freeze ups crushed the tubing.

What he said. Inadequate defrost cycles.

[BALloyd]

What he said. Inadequate defrost cycles.

X3....what they both said.

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[Str8Texan]

It could have been ice. I can't imagine how an outside force could damage that tube and leave the tube beneath it unscathed??

[Poodle Head Mikey]

Yes. It was ice. Pump down and isolate the evap, cut back the fins to find round tubing and add two 90's, two street 90º, and a short length of tubing to replace the flattened areas.

PHM
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Old, small grocery store. Low temp rack low on charge. Walked to store with my leak detector and it goes nuts in the walk-in freezer. Narrowed down to the evap coil that’s leaking, pulled panel on end with TXV and start checking with bubbles… no leaks. Check all joints, no leaks. Thought I heard gas escaping, but couldn’t narrow it down so I got a young employee and borrowed his ears. He says it’s coming from the fins in the back. He takes a Sharpie and circles the area for me.

I start pulling the aluminum fins out, and this is what I find.



Only this one tube, and only in this one evaperator. I’m guessing that at some point in its life, a buildup of ice caused this damage, what do you think? Anyone else ever run into this?

[Poodle Head Mikey]

Oh. That is not what I would have done. How many passes were disabled by this repair?

PHM
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Oh yeah… The fix

[Poodle Head Mikey]

I have always puzzled about that - it doesn't seem that ice could 'crush' by encircling. It seems like it would have to be reacting Against something in order to push inward. But if that was the case - how come the other thing isn't also crushed? <g>

The coils that do this seem to have had the fins clogged in the area of the crushing. Sometimes a piece of paper that remains stuck to the coil. I project that maybe a clump of residual ice clamps to the fins so tightly that that ice itself becomes the 'backstop' for the inward-crushing ice's force.

But I'm not really sure - I just pondered the 'why' of it at times.

PHM
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It could have been ice. I can't imagine how an outside force could damage that tube and leave the tube beneath it unscathed??

[GenesisRefrig]

I disabled 3 passes. There are three evap coils. I wasn’t confident I could braze an ell so close to the end plate with tubing that was still out of round.

[Poodle Head Mikey]

You're a good man Gen. But you must always strictly discipline yourself to avoid over-caution. It is a weakness that must be beaten back. Stop doubting yourself.

PHM
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I disabled 3 passes. There are three evap coils. I wasn’t confident I could braze an ell so close to the end plate with tubing that was still out of round.

[GenesisRefrig]

LOL

[Out in the cold]

This one brings up some memories for me. As a kid (15 or so) I used to work on hundreds of GE ptac units in the shop that were in warranty. They were heat pumps for hotel rooms. Some of the early ones-zoneline 4000's and 5000's - I think didn't have a drain valve in the pan for condensation draining. Water stood in the pan and then froze collapsing the bottom 2 ir 3 rows of outdoor coil tubing exactly like this. My fix was pulling the return bends and the tubes and then sliding in some new 5/16 tubing and reinstalling the return bends. If you were careful the return bends could be reused, otherwise I'd pull a few off scrappers to be reused. I may indirectly be responsible for the invention of the thermostatic drain valves they use today. I charged many thousands of $ to GE for warranty work over that and other problems!

[R600a]

This one brings up some memories for me. As a kid (15 or so) I used to work on hundreds of GE ptac units in the shop that were in warranty. They were heat pumps for hotel rooms. Some of the early ones-zoneline 4000's and 5000's - I think didn't have a drain valve in the pan for condensation draining. Water stood in the pan and then froze collapsing the bottom 2 ir 3 rows of outdoor coil tubing exactly like this. My fix was pulling the return bends and the tubes and then sliding in some new 5/16 tubing and reinstalling the return bends. If you were careful the return bends could be reused, otherwise I'd pull a few off scrappers to be reused. I may indirectly be responsible for the invention of the thermostatic drain valves they use today. I charged many thousands of $ to GE for warranty work over that and other problems!

I'm pretty sure Amana heat pump PTAC units shut off below 35° or something like that. I wonder if that's to help prevent too much problems with ice?

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[Out in the cold]

It actually didnt matter if it ran or not. Once water was in the pan from running in a warmer ambient it froze as soon as the temperature dropped a couple days later. No time to evaporate.

[R600a]

It actually didnt matter if it ran or not. Once water was in the pan from running in a warmer ambient it froze as soon as the temperature dropped a couple days later. No time to evaporate.

I didn't think about that.

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[causa]

I repair that type of failure with soft copper slightly largerand a install a Swede in the ends to pitch to size and weld it up.

Had to do it on many a condenser.

[TechmanTerry]

You're a good man Gen. But you must always strictly discipline yourself to avoid over-caution. It is a weakness that must be beaten back. Stop doubting yourself.

PHM
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X2 & X3