The correct diameter depends on required flow, pressure, run length and system design. A plumber should calculate larger heating and supply runs rather than relying on a rule of thumb.
Copper Tube and Jointing Parts for Plumbing Runs
MacBlair stocks copper tube in common plumbing diameters, including 15mm, 22mm and 28mm, plus chrome-plated 15mm tube for visible runs. The range also includes end-feed elbows and connectors, solder-ring reducers and tees, and push-fit Tectite fittings.
Pipe size should be based on flow, pressure, run length and the connected appliance, not simply the nearest existing tube. Use compatible pipe fittings with clean, round tube ends and support the run at the spacing required for its position.
End-feed and solder-ring joints need careful cleaning, flux control and heat protection. Where a flame is impractical, compression connections or an approved push-fit system may be considered. Gas work remains restricted to a properly qualified Gas Safe engineer.
Insulate hot pipes to reduce heat loss and protect vulnerable cold-water runs from freezing. Complete heating work with the specified system cleaner and inhibitor, then test all new joints before concealing the pipework.
Copper Pipe FAQ's
Yes. Approved compression and push-fit fittings can join correctly prepared copper tube. Check the fitting instructions and pressure rating for the service.
Use a pipe cutter that produces a square cut, then remove internal and external burrs without reducing the wall thickness. Keep swarf out of the system.
Yes, with a compatible transition fitting. Fit the plastic manufacturer’s pipe insert and follow the stated insertion depth and jointing method.
Insulation reduces heat loss from hot-water and heating pipes, limits condensation on cold runs and helps protect pipes in vulnerable spaces from freezing.