One common plumbing repair issue that homeowners or plumbers face is connecting a plastic pipe (PVC) to a metal pipe (galvanised steel). The two things to remember are to always have a good seal using Teflon tape over the threads, and to always thread the PVC into the metal pipe. These transitions typically occur in older homes with metal piping, in various sprinkler systems, or when repairing hot water heaters.
Remove any galvanised pipes as needed at the joint closest to where the PVC will be installed. Discard the unneeded section of galvanised pipe. Clean the threads of the galvanised pipe where the transition will be made, using the wire brush.
Wrap the threads on the galvanised pipe with the Teflon pipe tape in a clockwise direction, starting at the end of the pipe and wrapping the tape up the pipe until the threads are completely covered.
Connect one end of the female-to-female fitting on the end of the galvanised pipe. Tighten the fitting using the pipe wrench.
Cut the PVC pipe to fit as needed and remove any burrs or debris using the deburring tool. Apply cement to the inside of the slip end of the male PVC fitting and to the outside of one end of the pipe. Slide the fitting over the end of the pipe and twist it down until the end of the pipe abuts the inside ridge in the centre of the fitting.
Apply Teflon thread tape to the threaded end of the male PVC fitting, in a clockwise direction.
Insert the male PVC threaded fitting into the female galvanised threaded fitting and thread the two fittings together to complete the connection. Tighten the connection with the pipe wrench.
- It is always important to remember to thread a PVC pipe into a galvanised pipe, rather than vice versa. Threading a metal pipe into a plastic pipe can cause the plastic pipe to spread, leading to unforeseen leaks.
- Avoid over-tightening the PVC fitting into the galvanised fitting as this could strip out the plastic threads.
- Avoid direct breathing of the cement fumes as this could cause serious internal injuries.