Conversion to fully pumped - help!

Discussion in 'Plumbers' Talk' started by bart, Nov 6, 2003.

  1. bart

    bart New Member

    I have just installed underfloor (water) heating in an extension and need to connect into my CH system.

    The system is pumped rads and gravity HW. Unfortunately the pump is on the RETURN to the boiler and is situated up in the airing cupboard- is this a problem ? Where do I put my TRV's? I was planning on 3 off 2- ports for CH, HW and underfloor. Do I need to fit non return valves? And where? Any help very much appreciated.
     
  2. bart

    bart New Member

    Sorry - I don't mean TRV's - I mean where do I put the 2-port motorised valves (Duh!)
     
  3. SteveK

    SteveK New Member

    The pump being on the cold side of the boiler means that there will be less tendency to have problems on pump performance. The whole system is sealed from the pump discharge , through the boiler and around the system and back to the head tank connection. The connection to the head tank will be on the pump suction side. Any valves added must not isolate the head tank connection from the pump, but other than that carry on regardless.
     
  4. chtechie

    chtechie Member

    Is this a DIY system? I know Nu-Heat systems supply a specific wiring centre.
    However wiring should be faily straightforward - Assuming you've wired DHW & CH as a standard S plan in a 10 terminal wiring centre(WC). Connect your underfloor zone stat T1 to WC4, T2 to WC2, T3 to WC7 (or other unused terminal). Connect your zone valve Blue to WC2, Orange to WC10, Brown to WC7 (or same terminal as your stat T3), Grey to WC1, Green/Yellow to WC3. That should work fine.
     
  5. bart

    bart New Member

    Thanks for the advice.

    The existing system is an Olympic boiler (which works fine!)with 28mm grav primary and pumped rads.

    The u/f heating is supplied by Continental and accepts 22mm flow and return from boiler and has it's own pump, control box and thermostat around the manifold - I have fitted it myself - following their vgood instructions.

    The tricky bit is figuring out where to break into my main CH. I am planning on buying an S-plan pack (two 22mm valves, cyl stat, main stat, wiring box plus an additional 28mm valve for the return on the primary mounted close to the boiler input or tank output (ie. after the header connection). There will be two timers for the boiler - one for CH/HW and the other for UFH. In the end I should have controlled HW, Rad CH and UF CH albeit the HW will still be gravity.

    Does this sound OK?

    Thanks again
     
  6. bart

    bart New Member

    Note to SteveK - I have found the vent from the HW 28mm to the loft tank but no obvious vent from the CH side(22mm) of my boiler - is there likely to be one? In which case can I go right ahead and put my zone valves above the boiler output? Are they affected by heat? What about the bypass valve?

    Thanks again
     
  7. chtechie

    chtechie Member

    Well an S plan is fully pumped DHW & CH so you'll actually be installing a modified C plan. It's going to be a lot easier to convert to fully pumped! Is there a reason why you don't want to convert? Anyway assuming you don't you should only need to connected UFH wiring to L,N & E and your 'heat call' to WC10 on you CH wiring centre
     
  8. bart

    bart New Member

    I would love to convert to fully pumped but can't see how to do that and keep my existing boiler. The current boiler has seperate outputs for CH and DHW and the pump is on the return from the CH. I am unsure how to reconfigure pipework to achieve S plan. Any thoughts? I can't afford the new boiler just yet!
     

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