Coil gas leaks with R410a

[Bestseed]

excellant letter on recent rash of coil leaks with R 410a at this link Coil Corrosion

I for one have great hesitation on installing any R 410a system until this is honestly explained and resolved in a believable way by all manufactures. This is my primary concern and worry that I too will be hit with $500-$1000 repair bills even with warranty covering parts and I would have no heat or AC for days or weeks with a R 410a leak. Tin plated U bends, e coated coils , forget it, has not helped. Find the real cause and a real long term solid solution or No Sale.

[Mark Custis]

I heard the same stuff when we went from R-12 to R-22. One needs to practice good refrigeration practices no mater what refrigerant a system uses. I like propane and CO2.

The big issue I see is the oil required for a R-410A system will absorb water. Water and refrigerant will produce acidic situations and cause perforation of the system. Since the coils contain the thinnest tubing, that is where the leaks form first.

A good vacume and a new filter dryer is a must for any service, or manufacture work.

Mark

[urthbuoy]

Indoor air has changed with the mechanical ventilation nowadays vs. leaky house of yesteryear.

[StevieB]

When I worked at Heil-Quaker aka Tempstar aka ICP, I spent a great deal of time studying formicary corrosion.
This was the early to mid 90s. We and the bulk of the industry suffered from the outlawing of triclorethylene in the coil cleaning process. Process oils were left on the copper. We also dropped the wall thickness to, I think, .013 from .015 inches. This was also the time rifled tubing was becoming the norm. When the expander was run thru the copper to get contact with the fins, some of the fins split. This split would hold moisture during cooling. When it dried a crystal was formed that began the corrosion. When it got wet again, the corrosion took over where this crystal was. This process repeated over and over. The reason the path wandered thru the copper was this crystal would develop in different places in the corrosion path and the corrosion would follow that path. This entire issue was caused due to the change in the cleansing during our manufacturing. Any problem now could be driven by external factors.
When I first found this problem, I would bag one of the bad coils overnight with about 250 psi nitrogen / R-22 mix. When we could find the leaker, we would dip the coil under water. I stripped off the fins and that's when the cracked fin collars became obvious as the starting point. I potted the fin in plastic and ground it down to reveal the path. We replaced 1000s and 1000s of coils. It seemed the slab coils were the worst with the A coils coming in second. Interesting stuff when I was in my other life. As most know, ICP went to Carrier. Carrier took the label maker to Texas. I went to work for Siemens.
It has been a while since I gave this much thought. But that's my .02.
Side Note: I have a 2T Climatemaster with a 9/25/11 date code. So far all is well.