Grundfos TF110 blowing fuse

Discussion in 'Plumbers' Talk' started by Knowsome, Nov 2, 2018.

  1. Knowsome

    Knowsome Member

    Hi my daughters Grundfos TF110 circulator has blown its fuse. The CU is a fuse wired 1960 model. The pump was OK earlier today but blew its fuse later on when switching on via the room thermostat. The central heating boiler shares its own fuse which powers some lights in a utility room and the boiler "cupboard". I replaced the 5 amp fuse and it lasted 12 seconds before it blew. Some water had been getting in from a leaking valve. I tightened the valve and dried out any water I could see. I used a hot air gun to dry out the electrical connection box and replaced the fuse, to no avail. I am wondering whether the capacitor has failed?

    NB the house needs a replacement CU and I doubt that the boiler can provide enough heat in the future especially as she is thinking of extending the building to include loft rooms. The capacitor although old is not showing any signs of failure. It was warm to the touch - the upper part.
     
  2. spirits are real 2016

    spirits are real 2016 Active Member

    was the lights on and the boiler at the same time. If she is thinking of adding more rooms it sounds like a complete house rewire is needed
     
  3. Knowsome

    Knowsome Member

    Yes I know that. But my query is about the heating pump.
     
  4. terrymac

    terrymac Well-Known Member

    Which fuse is blowing ? The supply to the boiler / programmer / pump / and central heating wiring junction box would normally all be protected by the same fuse . what tests have you done to establish the pump is causing the fuse to blow .
     
  5. Knowsome

    Knowsome Member

    Thanks terrymac. the fuse supplies the programmer, room thermostat, utility room lighting and the lighting in the small boiler room. As some water had crept into the pump electrical connection box I have assumed it is the pump that has a fault. I replaced a light bulb as sometimes fuses blow when a light blows. The next step I think is to disconnect the supply to the pump and see if the fuse blows. And put a plug with a 3amp fuse onto the wire supplying the pump.
     
  6. terrymac

    terrymac Well-Known Member

    Is the pump in the same location as wiring centre ,had water got in there or onto / into any three port / two port valves ? It could be the pump or any number of other faults.
     
  7. heatyman

    heatyman Well-Known Member

    When faced with a problem like this, I isolate all the feeds, and reconnect one by one until the culprit 'owns up'. However, if the pump has got wet, just isolating this should give you the chance to meter it out. There is a multiplug type connector between the connector box and the windings, and you stand no chance of drying it out without disconnecting, and even then it is often unsuccessful.
     
    Knowsome likes this.
  8. Knowsome

    Knowsome Member

    No the only water had come from a slightly leaky valve above the pump.
     
  9. Knowsome

    Knowsome Member

    Thanks heatyman.
    If I do to have to replace the pump does the Grundfos UPS2 15-50/60 replace the TF110?
     
  10. Pollowick

    Pollowick Well-Known Member

    Is TF110 the pump or the temperature spec that it meets? Can you post a pic of the pump showing the full label?
     
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  11. Knowsome

    Knowsome Member

    Hi Pollowwick. Thanks it seems I have supplied the number on the capacitor not the pump. The pump is a UPS1550 No 403. No wonder I couldn't find it on Google. I note that if necessary I can buy the UPS2 as a replacement.
     
    Last edited: Nov 3, 2018
  12. Pollowick

    Pollowick Well-Known Member

    TF110 is the temp spec ...

    As for pumps, look at the Alpha 2L - a step up from the 15-50/60 but a direct replacement in terms of connections.
     
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  13. The Teach

    The Teach Well-Known Member

    iirc TF110 is Temperature of Fluid being circulated not to exceed 110°C but temporary over shoots are allowed.

    yes thats the replacement :) dont worry about the TF number.
     
    Knowsome likes this.
  14. Knowsome

    Knowsome Member

    Thanks Pollowick if necessary I'll follow your advice, its only a tenner more from Screwfix
    mbers' Talk.
     
  15. terrymac

    terrymac Well-Known Member

    Have you determined that the pump is the problem now ?
     
  16. Knowsome

    Knowsome Member

    No not yet terrymac. I will get onto it tomorrow.
     
  17. terrymac

    terrymac Well-Known Member

    Ah ,ok. Good luck with it ,do let us know how you get on
     
  18. Knowsome

    Knowsome Member

    Yes thanks once again!
     
  19. Knowsome

    Knowsome Member

    Hi terrrymac. I disconected the pump supply and the system works OK now. leaving the boiler on I hope to dry out the pump. Tomorrow I'll reconnect it. If it doesn't work its a new pump. I did try to find out whether the pump had seized, it did a week or so ago. It is free to turn, and turns easily.
     
  20. Knowsome

    Knowsome Member

    Yes thanks, isolatimg the pump enables the system to run fine. I have left the boiler on the hot water should dry out the pump. Tomorrow I'll reconnect it. If it fails I'll buy a new pump.
     

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