Heating System Problem!!!

Discussion in 'Plumbers' Talk' started by Sparkyjumper, Dec 14, 2009.

  1. Sparkyjumper

    Sparkyjumper New Member

    I have a potterton 80 which has been playing up. Water has been coming out of the discharge pipe into the garden. I have been told there is a possible faulty with the expansion vessel. It have also been suggested to fit X200 which I bought from ScrewFix which I have done, now making me have to reduce the bar pressure of 3 down to 1 by removing three cups of water from the radiator system three times in seven days. Am I correct in doing this and approximately how long will I have to countinue reducing the 3 bar pressure?
    If this doesn't work, how difficult is it to fit a expansion unit to the potterton 80 as looks like the expansion unit is located behind the heat exchanger etc? or is a external one easier to fit and how?
  2. Slap Dash Harry

    Slap Dash Harry New Member

    Check the filling loop, sounds like it is leaking by valve and pressuring the system,
  3. doing a bit

    doing a bit New Member

    if the system pressure is constantly increasing either your filling loop is open partially or the hot water heat exchanger is allowing cold mains into the system therfore increasing the pressure , drop off the system pressure and check the charge pressure in the exp vessel , should be about 10psi , suspect leaky heat exc though
  4. PTFE

    PTFE Member

    Before you start trying to replace parts you need to find the cause of the pressure rise.

    From what you say this is likely to be:
    - your filling loop may be allowing mains pressure water into the central heating system. Disconnect it and see if the problem persists
    - you may have a pin hole in the heat exchanger allowing mains pressure water into the central heating system.

    So try disconnecting the filling loop (don't just turn it off cos maybe it's not shutting off properly), actually disconnect it.

    As for the X200. Who suggested you use that and for what reason? Do you suspect your boiler is scaled up?
  5. PTFE

    PTFE Member

    wish I could type faster! :)
  6. doing a bit

    doing a bit New Member

    ditto :^O
  7. Sparkyjumper

    Sparkyjumper New Member

    t the
    thanks PTFE and others. i completely disconnected
    the filling loop and since 15th December yipee no rise
    in pressure - it remains at 1 bar and no water from
    expansion pipe into garden.

    my original fault was losing pressure via the expansion
    pipe right down to zero pressure. i was told that there
    could be a problem with the expansion unit in boiler
    because afer running a bath the rsdistor in the bathroom
    got hot - after fitting the X 200 there has not been any
    water coming out of the expansion pipe so the X200
    must have got rid of some of the limescale

    any thoughts you may have
    regards Sparky jumper
  8. doing a bit

    doing a bit New Member

    after the boiler has run for a while on hot water only heat will build up in the exchanger , this has to be dissipated through the system, your bathroom rad is probably the one with no trv so will allow heat through constantly and dissipate whats built up , pump overrun basically

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