1. We are pleased to announce the 'Home Automation' forum. Click here to get involved!

Weird Heating System - How Do I Change To S Plan

Discussion in 'Plumbing and Central Heating' started by 3500P5BV8, 24 Jan 2010.

  1. 3500P5BV8

    Joined:
    11 Jan 2008
    Messages:
    66
    Thanks Received:
    0
    Location:
    Cornwall
    Country:
    United Kingdom
    It appears that my brother has bought a bungalow with an unconventional heating system, that doesn't fall into any category (eg. Y, C, S plan)

    Its like a C plan, but the single 2 port valve is on the heating flow. The HW has no control valve, so whenever the heating is on, the primaries on the cylinder are also being pumped from the boiler too.

    He wants to replace the ancient boiler. Can we convert to S plan, by adding a 2 port valve to the cylinder primaries? Obviously the wiring would need to change too, but what other changes are necessary?
     
  2. bellairaphon

    Joined:
    25 Jun 2008
    Messages:
    950
    Thanks Received:
    111
    Location:
    Yorkshire
    Country:
    United Kingdom
    Thats all you need to do add the valve repipe to the cylinder add a bypass and wire the thing up. might be worth while getting a full s plan kit. And if your changing the boiler i think that you might be putting it onto a pressurised system. so a pressure test of the system should be done.

    Nath
     
  3. marcr

    Joined:
    23 Nov 2009
    Messages:
    120
    Thanks Received:
    15
    Location:
    Bath
    Country:
    United Kingdom
    Agreed, apart from the pressure bit. Is it open - vented at the moment? ie header tank in the loft? A bit of prep work would be advisable. How do the rads perform at the moment? What's the state of the water in the tank? Could you introduce a couple of litres of gentle system cleaner for a couple of weeks?
    I would take the opportunity to get a full lifestyle pack, 22mm bypass (auto) and new pump with quality valves maybe. and new rad valves which can be easily swapped.
    Once drained down the existing zone valve should be swapped for new, tee in/pipe up hot water valve and bypass and upgrade wiring to new programmer with cylinder stat in series with new valve.
     
  4. 3500P5BV8

    Joined:
    11 Jan 2008
    Messages:
    66
    Thanks Received:
    0
    Location:
    Cornwall
    Country:
    United Kingdom
    Thanks for the advice.

    He wants to keep it vented, and change as little as possible as it works really well.

    2 more questions.

    1) Where would the bypass go? Between the primaries on the cylinder (obviously before the new motorised valve, which would be on the cylinder primary flow)?

    2) Would it be within regs to leave the system as it is, but just replace the boiler?
     
  5. 3500P5BV8

    Joined:
    11 Jan 2008
    Messages:
    66
    Thanks Received:
    0
    Location:
    Cornwall
    Country:
    United Kingdom
    Below is a sketch of the system, with the addition of the new 2 port valve for HW. Would this be the correct position?

    Also shown is the position where I think the bypass should go. Is this correct?

    If we were to have just the boiler replaced, without the other changes, would this be within the regs?

    (N.B. the feed and vent pipes aren't shown, but are above the boiler.)

     

Share This Page