Grunfos pump impeller direction?

Discussion in 'Plumbing and Central Heating' started by toxycbob, 20 May 2011.

  1. toxycbob

    toxycbob

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    Hi new here and would appreciate some advice. My central heating failed recently. After reading a few forums I checked the pump( Myson) at the bleeding point the spring loaded screw wasn't turning so purchased a new Grunfos pump and fitted. The system now fires up pump is running but after a minute or so boiler overheats and cuts off. Again after reading another post suggesting pump flow direction should be pointing down because pump is connected to upper outlet of boiler so done this still same problem. My concern just now is when I removed the head to check that the impeller was turning it looks as though it is running in reverse e.g not a scooping action. Is this correct. I have wired it as instructed L to L ,N to N and E to E. When it overheats the pipes at the pump are not hot yet but with conduction eventually heat reaches pipe going into pump at top first. Any suggestions please.
     
  2. weareleeds

    weareleeds

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    Depends on system type etc which way pump should be pumping ie gravity fully pumped etc need more info but it may be just air-locked is the system full of water at rads and circs at cylinder etc
     
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  4. D_Hailsham

    D_Hailsham

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    The arrow on the side of the pump must always point in the direction of flow. So if the pump is on the flow pipe it will point away from the boiler and if on the return it should point towards the boiler.

    Ideally the pump should pump downwards, but the pipe layout may prevent this.

    Did you drain down to change the pump?

    Did you make sure all motorized valves were in the Man position when refilling?

    Have you bled the pump and all radiators?
     
  5. toxycbob

    toxycbob

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    Thanks for the reply guys. It is a gravity system just after I posted this question I turned the speed of the pump up to full and tried again and it has been running for the last hour is this common that the pump is at position 3 as the Myson was always at 2? Everything that bleeds has been bled so I hope problem solved. "Her indoors" was for strangling me last night! Browny points today maybe...
     
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