Central heating

Discussion in 'Getting Started FAQ' started by BootsieB, Jan 13, 2021.

  1. BootsieB

    BootsieB New Member

    Have fitted new central heating pump and is pumping into header tank and out through overflow
     
  2. terrymac

    terrymac Screwfix Select

    Why did you fit a new pump ?
    Was the same thing happening with previous pump ?
     
  3. BootsieB

    BootsieB New Member

    Old pump was knackered.Have had 2 pumps in45 years and this has never happened before.All pipework is clear and pump is on lowest setting
     
  4. terrymac

    terrymac Screwfix Select

    Blockage on feed pipe , possibly. Run a magnet down the pipe from F&E . If it's blocked the magnet will be attracted to the pipe.
     
  5. BootsieB

    BootsieB New Member

    No blockages in any of the pipework
     
  6. Joe the Plumber

    Joe the Plumber Screwfix Select

    Is the direction of flow (arrow on pump body) the same on the new pump as the old one was?

    If it's back to front, it might cause the problem you're having.
     
  7. BootsieB

    BootsieB New Member

    Pump is in correct direction etc to create
     
  8. Severntrent

    Severntrent Screwfix Select

    I have a similar problem and after running central heating and DHW in various different modes with radiators isolated, pump at different speeds, DHW and central heating separate or together, (various quantities of overflow being observed) I have decided that there is a restriction/blockage at point x. If there was no blockage the pump would pump flow around at ? l/s and be able to suck water from point x at ? l/s equilibrium being maintained and there would be no excess flow to be pushed up the expansion pipe. Since there is a restriction at X the pump cannot be supplied the necessary ? l/s and therefore it makes up the shortfall by taking it from the header tank fed pipe, this in turn means that all the flow of ? l/s arriving back at point x is not required by the pump and the excess discharges up the vent pipe, flow is then constantly circulated through the header tank and back towards the pump suction pipe, equilibrium now being maintained i.e. ? l/s in and ? l/s out.

    I attach a simplistic configuration diagram showing point x and a photo of the actual layout of my possible restricted area which I believe is within the air separation chamber. I'll put theory to the test when the cold weather has stopped and the wife lets me turn off the heating, Watch this space. Screenshot (541).png Screenshot (543).png
     
  9. BootsieB

    BootsieB New Member

    Thanks for that .Will give it a go
     
  10. BootsieB

    BootsieB New Member

    Thanks for that .Will give it a go
     

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