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Heating upgrade 28mm or 22mm pipe old house refurb

Discussion in 'Plumbing and Central Heating' started by d.o.n., 20 May 2021.

  1. d.o.n.


    24 Dec 2005
    Thanks Received:
    United Kingdom
    I've recently purchased a large old uninsulated house-im saying recently but owned it for 3 years.
    The existing pipework looks to be original and is huge i would say looking at it 3-4 inch in diameter.

    Its a single pipe system so the downstairs from the boiler room runs under the sub floor from the external boiler room in this size pipe then tees off in smaller pipework which then goes to each radiator-it looks to be threaded galvanised pipework,so this is partly heating an unused vented under subfloor which seems crazy.
    The upstairs heating pipework goes through the loft and consequently heating a cold loft.

    The heating is an old oil boiler-floor standing myson-looks at least 30 years old to me,after running for an hour the rads are relatively cool and after about 2 hours they get a bit hot but by this time its drinking oil like crazy so don't really want to use it more than twice a day at 2 hours otherwise it would go through a few hundred pounds worth per month easily

    I'm thinking of maybe trying to repipe in either 28mm flow and return and then reducing or would 22mm flow and return suffice.
    Also thinking of renewing boiler to something along the lines of a grant vortex.

    Would plastic hep20 be OK or copper or a mix.

    Also the house looks as if its got most of its original cast iron school type radiators.

    After 2 hours running the degrees roughly go up by 1 degree in the house,it runs approx 20 radiators shared between upstairs and downstairs.
    Heating pipework and rads look original to the 1930s build so you've got to give them credit that it still works,but I think it would of originally be ran by coal and then swapped over maybe in the 1960s-1970s to oil.

    Any help much appreciated
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  3. muggles


    28 Oct 2005
    Thanks Received:
    United Kingdom
    What size pipework you need depends on how much power you need to distribute and length of the runs. Have you done a proper heat loss calculation on the property? If not, that's the best place to start. www.heat-engineer.com will give you an accurate picture of what you actually need to heat your house, and from that the pipe sizing can be calculated.

    Might be worth considering ditching the Myson at the same time and getting a more efficient boiler. Again, Heat Engineer will assist with finding the correct output.

    Finally, consider increasing insulation levels. Insulation and draught-proofing are cheap and easy ways to reduce your heating bills
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    3 Sep 2019
    United Kingdom

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