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Central Heating

Replacing back boiler system which is in the front room for new condenser boiler in the kitchen.

One fitter has said all floorboards from back room above where boiler is to be fitted, to the bathroom where the water heater is, have to be lifted up so piping can be fitted to supply hot water to the bathroom and kitchen and another fitter has said boiler can be connected to existing hot and cold pipes under sink in kitchen to supply hot water in kitchen and bathroom , I am now really confused and need some clear advice.

Thank you

2 Answers from MyBuilder Heating Engineers

Best Answer

your existing boiler or back boiler needs to have old pipe cut and capped off, the more you can remove the merrier, the new boiler if it is a combi can be connect virtually any were the hot and cold pipes are for potable water ( in this case you will be removing the Attic tank cold water supply and becoming a mains system) and tied back to flow and return on the central heating. if its a standard hot cylinder set up then it goes any were also within regs of the boiler flue and pressure relief plus condensing line ,there are regs that apply to placement for any boiler regardless of its style, it just needs to be tied back in too the flow and return lines for central heating that are left and existing, (in a nut shell). I hope that helps figure it out for you.


Answered 30th May 2011

Hi, your central heating pipwork has to be re-routed from under the boards to the new boiler position.

With regards to the hot and cold water supplies to the new combi, the cold mains supply to the combi may be taken from the kitchen, as may the hot supply.

I would however advise that the hotnd colda be re-piped in 15mm to the bathroom as your 1st engineer has suggested, the reason for this is because, your existing hot water system will utilise 22mm pipework, this can cause pressure loss within the pipework. Its not really a problem if your only feeding a bath however it can be a prob if you are also feeding a mixer shower for example.

Hope that clears things up.



Answered 31st May 2011

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