Wastewater refrigerant lineset failure / alternate materials

[jswin]

Got called out to look at some refrigerant lineset failures happening at wastewater building on split 410A DX, under 5Ton. Leaks at joints. Liquid and suction lines are field fabricated from copper and have turned black. Still tying to find submittal to see what they used to braze. Not a corrosion guy, but suspect hydrogen sulfide attacked.

Spec called for closed cell insulation with pvc jacket for both lines. Obviously somebody missed that part.
Here are my questions
- for those who have used copper lines in this type of environment, any suggestion on coating or other to protect from happening again.

- Anybody used an alternate material for lineset. Maybe 304L stainless? What about material for joints?

Thanks for your help

 

[trashcanman]

Copper should not be used where there is presence of NH3 (ammonia). NH3 can be present at a wastewater plant (byproduct). Refrigerant piping should be steel as a precaution.

You might check to see if NH3 is there. If so, it will attack CU and brazing (CU is in the brazing material).

 

[gscrivener]

stainless will work but very expensive and almost impossible to find any clean enough for refrigerant lines. I have seen very good results using epoxy coatings in corrosive environments.

 

[jswin]

Yeah, haven't had much luck finding ACR stainless steel. I have found polyethylene coated copper with field wrap joints by one manufacturer. Do you have a link to a source for epoxy coated? I assume joints are field applied coating.

 

[gscrivener]

We have used a brush-on product in corrosive agricultural environments but I can't remember exactly what it was. I've also done work on a job where it was professionally applied and I think it was the same epoxy coating as the floor... but I can't confirm that.