Posting a message to the forum will remove the above advertisement
  1. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss New Danfoss oil pumps / bypass screw in the Oil and Solid Fuel Forum area at

  1. Gazzt

    Gazzt Active Member

    Just to warn oil boiler engineers, new danfoss oil pumps come setup for a two pipe system, so you have to remove the bypass screw for single pipe installation. It will save you time cleaning soot out and potentially damaging the new pump.
    • Informative Informative x 2
  2. Best

    Best Trusted Plumber

    I must look out for that! Most boilers are still single oil pipe and oil hose
  3. johnf

    johnf Active Member

    I can't see any logic in doing that as most oil boilers run off a one pipe system as Best has said. Thanks for the heads up though. Good old Danfoss!!
  4. Gazzt

    Gazzt Active Member

    I know its really annoying, i have went to quite a few jobs handymen have fitted a new pump and it left a sooty mess.
  5. heliotrope

    heliotrope Plumber GSR

    Probably to save the cost of the little plastic bag that they
    packed the screw in.;)
  6. Theboilerman

    Theboilerman New Member

    Is it just the 21's? The 11's you have to remove the horseshoe washer so I'm assuming that is still the case. But will defo bear in mind!
  7. Inverness

    Inverness Plumber GSR

    Can you explain further... if I buy a new danfoss oil pump you say it's set up for a two pipe system so I need to remove the bypass screw? Where can I get the instructions so I can further my learning.cheers
  8. Last Plumber

    Last Plumber Plumber GSR

    Most pumps come with a screw in a little bag that you insert if you need to run it on a two pipe system. This is because you are using two ports on the pump and the internal by pass is not required, so you use the screw to close it off.

    I have (as mentioned above) come across one recently with the screw in place. I am pretty sure that was a Danfoss Pump (Odd thing to do in my opinion, I cannot see the logic).

    If you run a pump on a one pipe with the screw in place, it can damage the pump.

    The pump I bought came with no warning that the screw was inside the pump already.
    Last edited: Oct 19, 2017
  9. heliotrope

    heliotrope Plumber GSR

    I hope this is not a wind up but ok I will bite.

    The instructions for the pump will be packed in
    the box with the pump.
    • Funny Funny x 1
  10. Last Plumber

    Last Plumber Plumber GSR

    Not in the one I bought, no.
  11. Gazzt

    Gazzt Active Member

    It seems to be in the bfp21, it isn't clear in the instructions, i was warned by my plumbing merchants also about this problem.