central heating pump flow direction

Discussion in 'Plumbing and Central Heating' started by jake47, 28 Oct 2010.

  1. jake47

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    Hi ime not a plumber so go easy new here .Due to lack of finances ime fitting a grundfoss central heating pump myself as the old one died on me,stupidly i forgot to take note of the arrows on the original pump re the correct direction of flow.The pipework i can see is some way from the back boiler and is horizontal and i am unable to see which pipe is the flow and which is the return.So my question is how can i tell which way round to fit the pump ?should the arrow go from right to left if the right pipe to the pump heats up first or is it the reverse@help as ime worried about knackering the system. sorry if this is maybe a stupid question ,.
     
  2. stratovarius692

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  3. D_Hailsham

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    Although most systems have the pump in the flow, some manufacturers will allow it in the return.

    Maker and model of boiler?

    Was the previous pump a Grundfos?

    Can't you remember which way round it went from the physical location of the cable, controls etc?
     
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  4. kevplumb

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    won't help if the head's been turned tho :cry:
     
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  5. jake47

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    Hi again thanks for your replies i took the head off to check the seals etc the boiler is a Baxi Bermuda 51/5 (back boiler)installed about 6 years ago .The pump is in a cupboard about 10 foot away and the pipes disapper under the floorboards.Oh and the pump ive replaced is identical its a Grundfos Selectric type ups 15-50 130 pn59525609 if thats any help.
     
  6. Agile

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    Whilst modern practice is to fit the pump in the flow, when most bacl boilers were fitted many were in the return. It sounds as if yours was a replacement BBU so the pump could have been either way round.

    A little trick is to look at the dust on the old pump which would indicate which way up it was.

    If you really cannot decide then you could fit it either way and see what effect that has. However, thats potentially dangerous and really my advice would be to get a boiler engineer to advise.

    Tony
     
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  7. jake47

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    Thanks for the links, however if i dont know and cant see from the pipes which is the flow and which is the return i cant know which way the direction of flow should go.

    XX update ime still not sure but i think the direction of flow out of the pump is towards the return so i have put on the heating water and rads and fired it all up and as of now the rads are warming up starting with the upstairs, the pump itself is not making any strange noises so fingers crossed its ok , ime still not %100 and wonder if it was incorrect would everything warm up ok and there be no flashing light at the boilers electronic control which at the moment is showing a constant green light whilst the boiler is lit.
     
  8. Agile

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    Whilst you may not be able to notice the problem if its wrong then the boiler stat will not control the flow temperature correctly and would need to be set very low to achieve a sensible flow temperature.

    You would also find that for the first minute of starting from a cold system the boiler stat would not turn off the boiler as its turned down.

    But there is a 50% chance its correct.

    There is also a 50% chance that its incorrect.

    Tony
     
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  9. kevplumb

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    cobblers

    how in the h ell is it dangerous

    just won't work right

    ---------------------------------------
    do you have any of these ?
    :?:
     
  10. D_Hailsham

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    Do you mean that the arrow on the pump is pointing towards the boiler?

    The 51/5 installation instructions only show the pump on the flow; no mention is made of having it on the return. The arrow should point away from the boiler if it is on the flow and towards the boiler if it is on the return.

    Can you see any of the pipes connected to the boiler? If so, the upper is the flow and the lower is the return.

    Can you get access to the boiler connections? If so tap the pipes with a hammer and see if you can feel the vibration at the pump connection.

    If the lower connection has a Tee connection immediately adjacent to the boiler, then your system has gravity circulation for the hot water.
     
  11. Agile

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    I appreciate that you are only an armchair adviser who reads information but dont actually do practical work yourself.

    However, whatever the installation instructions say there is no reason to believe that any boiler has been correctly installed unless you check it on site. We cannot assume anything. In any case the OP has said that he has lost touch with how the pump was fitted before he touched it.

    I also appreciate that you may not be aware of how BBUs are arranged. That means that without dismantling gas parts, its not possible to see the flow and return pipes.

    Connecting the pump wrongly means that the boiler is not correctly controlling the flow temperature and that could cause the system water to exceed 100°C and boil.

    Tony
     
  12. Jake1886

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    OP maybe some photo's would help with us trying to identify the flow and return for you.

    Cool name by the way ;)
     
  13. kevplumb

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    kettle calling the pan black mister you know jack about the real world

    this from the man that has been shot down that many times he wears asbestos skids

    dave might be an armchair advisor
    but he will admit when he is wrong

    last time you did ????
     
  14. Jake1886

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    :LOL: :LOL:
     
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  15. jake47

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    Thanks guys armchair and otherwise it all helps and your quick feedback is appreciated :) .As the left pipe is coming from the direction of the boiler and the pump should be sited on the flow (according to the instructions)and it should pump away from left to right :arrow: ,thats what ive done and it seems to be ok .I think i would have to take up the floorboards to be 100% ,but all the rads are working and seem ok.So thanks again and btw jake is a cool name ,jakes united i say :D .[/u]
     

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