If your boiler and central heating system require condensate or overflow pipe then D4S Heating and Plumbing stocks pipe suitable for this requirement. The special pipe needs to be used for both condensate and overflow pipes and the diameter for this needs to be 21.5mm. Buy single pipes or in bulk.
21.5mm x 3 Metre White Condensate Pipe
Bulk 21.5mm x 3 Metre White Condensate Pipe (x10 Lengths)