Psi rating for radient floor heat panel test???

Johnny Mac said

My NPT fittings have however nearly ALL leaked with soapy water. Some ptfe thread paste, some Teflon tape, doesn't seem to matter. Tightened to fear of cracking.... can't seem to hold more than 35 psi in 24 hrs. I have repaired/redone all leaks used soapy water. Still leaks down from 40 to 30 over night. Seems to really hold there continuously.

Click to expand...

If the pipe threads were overtightened from the start, the fpt side could be distorted to the point where it will never seal. All good advise above from Del & everyone. The pump has a pressure rating too, so the shaft seal should be accounted for. If the fittings are overseas, lots could be wrong - the angle of each thread, the taper, etc.

Sure you don't have British Standard Parallel threads?

https://www.engineeringtoolbox.com/british-pipe-threads-d_754.html