1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Change in behaviour from unvented HW system

Discussion in 'Plumbing and Central Heating' started by orallyman, 19 Feb 2008.

  1. orallyman

    orallyman

    Joined:
    19 Feb 2008
    Messages:
    3
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi all

    My system was upgraded to an OSO 210 litre unvented cylinder on a new Grant Vortex oil condensing boiler with an S plan arrangement.

    All has worked well and I am overall very pleased with it. Until recently the HW has produced amazing pressure when first turning on the tap which has gradually reduced after a minute or two. I guess that this is due to the expansion vessel.

    In the last few weeks the system has altered; now when a tap is turned on there is a momentary surge of pressure (literally half a second or so) and then for a moment the pressure drops right down then up to roughly mains pressure.

    There also looks to have been some evidence of water coming from the tundish pipe outside the house (although I haven't actually witnessed any flowing).

    I am thinking that maybe the system needs 'repriming' (I don't know what the correct term is!)

    Any thoughts anyone?

    Thanks in advance.
     
  2. orallyman

    orallyman

    Joined:
    19 Feb 2008
    Messages:
    3
    Thanks Received:
    0
    Country:
    United Kingdom
    By the way the system was installed last July.
     
  3. Sponsored Links
  4. Nixt

    Nixt

    Joined:
    14 Dec 2006
    Messages:
    829
    Thanks Received:
    0
    Location:
    Essex
    Country:
    United Kingdom
    Problem with expansion. If separate vessel have it checked, if air bubble have it re-charged.
     
  5. orallyman

    orallyman

    Joined:
    19 Feb 2008
    Messages:
    3
    Thanks Received:
    0
    Country:
    United Kingdom
    It's an air bubble type. There is a procedure on the side of the cylinder involving opening taps/valves etc. Is this what I need to do?
     
  6. Sponsored Links
  7. Nixt

    Nixt

    Joined:
    14 Dec 2006
    Messages:
    829
    Thanks Received:
    0
    Location:
    Essex
    Country:
    United Kingdom
    Yes. If in doubt call someone in. Your unvented cylinder should be safety checked annually in any case.
     
  8. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page