When exactly are you supposed to use a poly liner? Seem to have a few in my box of water fittings but unsure when to use them.
Philmac Poly Liner MDPE, 32mm (1″) – Pack of 10, 78004 - Buy at H.P.W.
Philmac Poly Liner MDPE, 32mm (1″) – Pack of 10, 78004 available to buy online, with fast tracked delivery. Heating Parts Warehouse the specialists in plumbing and heating parts and spares.
heatingpartswarehouse.com