Is there a process to reline a 3/4" copper water line with 90's?

[Steven Rivers]

I have a customer with a high-efficiency condensing furnace in the attic above a third floor, installed with a copper line for the furnace condensate discharge. This line should have been run in PVC, as the combustion exhaust condensate is acidic. The line is inaccessible and buried in the walls or ceilings until it exits on the first-floor exterior. It is not blocked but has developed leaks, likely on the bottom of a horizontal run. The home is a townhouse with a very restrictive HOA that will not allow any alteration to the exterior of the building.

I believe there is a process that does not use a liner but may involve forcing an epoxy or resin product through the line to reline the tubing interior. The product is then blown out with compressed air before it is set. Does anyone know about this?

 

[Twowaxhack]

Install a condensate filter and pump then pump it to a pvc stack in the attic or wherever

 

[Steven Rivers]

Thanks for the suggestion! Yes, I'd hoped to do that, but the waste and vents are all cast iron. Using a neutralizer would help, but that requires periodic maintenance. Years from now, I wouldn't want any liability if there were a failure, as I can't imagine this being an approved solution if a lawyer gets involved. (The original installation was done 12 years ago and passed all inspections, so that company is probably in the clear now.)

Could a long tubing section be threaded through the existing line?

My idea is to use a vacuum at the outlet downstairs, tie a cotton ball (or something else) to a long fishing line, and suck the line from one end to the other. Use that line to pull a strong, fine-link chain through. Then attach the chain to some tubing (the tubing usually used with a condensate pump is probably too stiff), and pull it through the copper tube with mineral oil or other lubricant to help negotiate the turns. I'd do a test run before the attempt and see if 1/4" poly ice maker line tubing would make it through a few bends. The pump has a micro-switch that could break the thermostat wiring circuit if the float senses a failure.

My first idea of using epoxy or resin to reline the pipe was something another company would do, and I could turn this over to them. Over 150 townhomes were built in this subdivision, and this is not their first failure.