# plastic pipe for central heating



## rog (7 May 2011)

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?


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## villa 1 (7 May 2011)

Definitely no polythene/plastic pipe between the solid fuel boiler and the hot water cylinder(Gravity primary circuit) and none in the hot press area. I've seen this pipe completely collapse and disintegrate under boiling water conditions. As you said use 28mm copper for the primary circuit and as much as possible on the heating circuits.
This is ugly pipe in exposed locations and has killed the skill levels in domestic Plumbing. It will take pumped circuits as used for radiators but is best hidden. It is prone to airlocking, especially in open heating and domestic hot water circuits.
Advantages is that it is quick to install and is less prone to corrosion in soft/acidic water supplies.


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## DGOBS (7 May 2011)

+1. awful stuff, mice love it!

why do you think it is more prone to airlocking that copper? (because of undulation?)


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## villa 1 (8 May 2011)

Absolute disaster on low pressure systems whether it be heating or domestic hot and cold supplies.
Your right about the undulations as even the slightest amount will give poor flows to radiatiors and hot and cold outlets. Handymen love the stuff.
My pet hate is plastic/polythene connected directly to radiator valves and even worse is the tie-wrapping of supplies waste pipes in wash hand basins. Best of Cetlic tiger stuff


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## DGOBS (8 May 2011)

See even worse, right onto boilers and cylinders (should be 1.5m of copper at least!)
but your right, its rubbish


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