hot water plastic piping

[rog]

Hi, I'm installing a central heating / domestic hot water (solid fuel Rayburn multiburner range) vented/gravity feed system. I intended to use plastic piping except for the 28mm circuit and hot water takeoff from cylinder, however on checking pipe leaflets max service conditions for them are 92deg c with short term overload of 114degc. Occassionally in the past with a former system the water in the pipework would be heard boiling during cooking, remedied by turning on the central heating to cool the water temp; because of this possibillity am I correct in thinking that plastic is'nt suitable either for hot water or c/h in this relatively uncontrollable situation?

[Lobster]

Doesn't sound like it... certainly, the last time I had a (gas) boiler installed it came with warnings not to use plastic plumbing within X distance of the boiler. Don't the Rayburn installation instructions or website have similar specs? Would be surprised if not.

David

[polly filler]

I would use copper for the gravity serks 28mm, but you should also have a "heat leak", normally the bathroom radiator to take all the extra "heat" that the cylinder cannot take. For the heating you need to come off the boiler in copper for a certain distance "might be 2mts" then you can use plastic but I personaly would use copper, as plastic looks horrible going up the wall and into the rads. Plastics ok where you cannot see it like in the loft or under floorboards, but also it can get you out of difficult pipe runs occasionally. You will need a class 1 flue, and if it's internal, fire breaks where it goes through the upper floors.