gadolphus32
Member
I removed a hot-water cast iron radiator in my attic and need to cap the pipes, which are 1-inch black iron. As detailed in this thread, I can't get a black iron or galvanized cap to screw on, apparently because of issues with the threads on the pipes.
I was able to get PVC caps to go on and they seem to work (by which I mean they don't leak when the system is on) but I'm wondering whether I can trust them long-term.
I know PVC is rated only up to 140 degrees and circa 250 PSI. I don't know what temperature my boiler (installed in 1949) runs at, or how to check it -- but I don't think it is super hot because I can touch my radiators without burning myself, so I assume it's closer to 140 degrees than to 200.
I also don't know what pressure the system runs at because the gauge is broken, but from what I gather, a hot water radiator system should not be more than 30 PSI at the high end. I'm optimistic that the fact that the pressure on this system is well below the PVC maximum can help make up for the possibility that the temperature slightly exceeds the maximum.
Would you sleep comfortably with PVC caps on your radiator pipes? (If not, would you feel much better with CPVC, since it has a higher temperature and pressure rating? I haven't tried CPVC caps but I'm hopeful that they'd fit on, too.) And is this up to code? I can't find anything in the code about combining PVC with black iron; all I'm aware of are the maximum temperature and pressure ratings for PVC.
I was able to get PVC caps to go on and they seem to work (by which I mean they don't leak when the system is on) but I'm wondering whether I can trust them long-term.
I know PVC is rated only up to 140 degrees and circa 250 PSI. I don't know what temperature my boiler (installed in 1949) runs at, or how to check it -- but I don't think it is super hot because I can touch my radiators without burning myself, so I assume it's closer to 140 degrees than to 200.
I also don't know what pressure the system runs at because the gauge is broken, but from what I gather, a hot water radiator system should not be more than 30 PSI at the high end. I'm optimistic that the fact that the pressure on this system is well below the PVC maximum can help make up for the possibility that the temperature slightly exceeds the maximum.
Would you sleep comfortably with PVC caps on your radiator pipes? (If not, would you feel much better with CPVC, since it has a higher temperature and pressure rating? I haven't tried CPVC caps but I'm hopeful that they'd fit on, too.) And is this up to code? I can't find anything in the code about combining PVC with black iron; all I'm aware of are the maximum temperature and pressure ratings for PVC.