Unused legs in a central heating system?

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Apologies for the rather cryptic title...


I am in the middle of creating an open-plan kitchen/lounge/dining area and cannot with certainty decide where best to put the radiators. Indeed, I can envisage that the 'best' position might well change over time if/when the more mobile elements of the room move around.


I was wondering, therefore, if there would be any issue with me piping up a couple of areas to cater for the potential alternative siting of radiators at a later date? In keeping with the rest of the system I'll be using 10mm plastic piping run down from the ceiling behind the plasterboard so it'll be a straightforward job to do at this stage of the construction (the ceiling is currently down). The exit points are are at socket height (behind where the radiator would be) so I would just cap off the pipes in a back box and cover them with a blanking plate.


Once my project is complete there will be limited access to the ceiling space so I was planning on connecting all the radiator feeds up to the manifolds now hence the unused ones will likely be sitting there for a long time with either air or water in them. Does anyone anticipate any potential issue(s) with this?

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No issue at all - in effect an unused leg is just the same as a radiator on the circuit which is off. 


Water cannot move in it and you will not waste any heat. 


As with any plumbing setup the more connections and stop ends and valves and taps the more likely there is to be a leak, but I think it would be worth it if it enables a "perfect solution" in the end. 


I would however cap them all, fill the system and test or pressure test them. I made up a testing system with some push fit stop ends and one with a Schrader valve on it. I put some water into the pipes then pressurised the pipes with my compressor to about 3 bar and left it like that. You could use a bicycle tract pump or little car tyre compressor.

Edited by Carrerahill

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That's good to hear, thanks.


I'll be doing the plumbing work shortly and with the rest of the construction work likely to take some time (sigh!) there'll be plenty of opportunity to spot any leaks and the system should be well exercised given the heating season imminent. It's a sealed system so I've got the benefit of an always-connected pressure gauge to alert me to any small leaks that might otherwise be difficult to detect, although it wouldn't be going much above ~1.5 bar.

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