Grundfos (Danish pronunciation: [ˈkʁɔnˀfʌs]) is the largest pump manufacturer in the world, based in Denmark, with more than 19,000 employees globally.
The annual production of more than 16 million pump units, circulator pumps (UP), submersible pumps (SP), and centrifugal pumps (CR). Grundfos also produces electric motors for the pumps as well as electric motors for separate merchandising. Grundfos develops and sells electronics for controls for pumps and other systems.

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  1. C

    Grundfos Alpha 2 Wiring Connector

    Hi, I note that the Grundfos Alpha 2 requires a special plug to connect the electric wiring. Are those plugs reusable if rewiring is needed? It's an expensive plug, costing as much as a used Alpha pump. Suppliers of refurbished pumps don't supply a plug. Fine if it is a Grundfos like for...
  2. N

    Grundfos Alpha v UPS sorry cross post

    Hello, I have just had my 15year old Grundfos UPS 15 50 replaced with an Alpha 1 and the Alpha 1 seems quite a bit noisier than the the old one, I have a new UPS3 sitting in a box and I am thinking of changing the Alpha 1 for the UPS3 if I understand it correctly, Alpha1 v UPS3 1. Alpha 1 is...
  3. G

    Booster Pump Needs Reset Daily

    Hi, I am currently using a Grundfos Booster Pump. This pump is fed by 2pcs of 1,000 liters water tank. Normally the pump would stop working only when there is no water in the water tank. But, recently for the past week, in the middle of the night, the pump would stop working even though the...
  4. B

    Heating not working - Grundfos pump issue

    Hi all, I have an old Combi boiler for which the heating has stopped working. The hot water is fine, and I think I've isolated the problem to the pump. The pump is a Grundfos Alpha2, and it has usually has two numbers, but it is instead showing two dashes ( -- ). I think the propeller isn't...
  5. C

    Grundfos UPS3 setting

    Hello I have a gravity fed system with a header tank in the loft, a water cylinder and a 3 way valve. The header tank in the loft is OK and has water in it. When the 3 way valve is in the mid setting the pump and pipes are quiet, and in the CH setting all is quiet. But when its in the HW...
  6. B

    Grundfos UPM3 pump won't turn despite being clean

    Hi there, I've got a stuck Grundfus pump again, but this time the usual tricks don't work. I took it out, cleaned it, still won't turn. Hand pressed against the rotating bit, screw pressed in, no movement. Tried the same both plugged and unplugged. The black propeler thing won't budge. Is it...
  7. notsure

    Grundfos Pump Domestic, Speed control

    I'm making my own replacement for a boilermate 2000 controler. I need more electical information on the pump so I can work out how to control the speed on it. does anyone know where I can find detailed electical info for this not just "on off" it looks like the original controler used PWM to...
  8. S

    whats a more powerful pump then a grundfos ups 25-50 130

    Hi i have a grundfos pump 25-50 130 p/n 59525418 radiators downstairs are cold and upstairs hot after an 1-hr 2 hrs then the downstairs gets hot i think the pump i have is too weak would would be a more powerful pump to help with this ? thanks
  9. S

    Grundfos ups3 pump issue

    Ups pump issue Fairly recently, say 12 months ago, we had a new pump fitted. It's a grundfos ups3 15- 50/65 130. (We have a small expansion tank next to the large tank in the loft. So not a sealed system) After it runs normally for several hours it just stops working. The radiators obviously...
  10. WayneWindsor

    Grundfos Alpha2L issue

    Good afternoon we have recently had a grundfos alpha2L 15-60 130 pump fitted to our central heating system and we're experiencing an issue. Once the pump is on its working fine but for the first "cycle" in the morning the "Power on" light comes on but the pump doesn't start. I have to then...
  11. R

    Is Britherm pump a better choice than Grundfos

    Is Britherm pump a better choice than Grundfos for Vaillant ecoTEC Plus 400 15kW Heat Only Boiler Wiring is SPlan and the intention is to install Grundfos UPS3 15-50/65-130
  12. N

    Grundfos pump irregularities

    Hi everyone, We have had issues with our Grundfos UPS3 15-50/65 130 ever since installation. The builders created 3 sections in one space. Two in the kitchen and the third in the living room. The 3 sections have never worked in unison so one was disabled to leave one for the whole kitchen and...
  13. S

    Why won't my GRUNDFOS UPS3 pump stop running?

    Hi everyone Some very helpful people on this forum (hi John.g) sorted me out with some issues with a faulty installation of a Grundfos UPS3 back in Oct/Nov 2021. My CH system has been running like a dream ever since. Until this evening. For months we have been switching heat and/or water...
  14. D

    Grundfos noisy oil central heating

    Hi. We have a wolf oil central heating system, with a grundflos alpha 2 circulation pump. Sometimes it makes a tinkle noise ( like metal to metal) and sometimes not. With and without burner running. I removed pump and impeller is ok and clean. Bled system through. Nothing helps.
  15. dilligaf

    Grundfos Central Heating Pump Weak?

    Do central heating pumps lose their strength over several years and is it worth taking it apart and servicing it? Are the two seals either end 1 1/2 inch or 1 1/3 inch? What's the latest central heating pump should I need to replace mine (photo) like for like?
  16. duckbert

    Grundfos MQ3-45 - Weird Noise

    I have a Grundfos MQ3-45 feeding my domestic water from a ground level tank (filled from an RO system from the well). The pump is about 4 years old, with normal-heavy household use. Today it started making a bit of an awful noise - see the attached video. I disassembled the hydraulic end of it...
  17. Jonnyh88

    Help with setting Grundfos pumps.Single Pipe CH heating system.

    I'm trying to get to grips with a system I have inherited as a new home owner. I know that single pipe systems are crap and should be replaced, but that's not an option right now so I have to make sure what I do have is set up correctly. My bills are astronomical - £6-700 a month right now, and...
  18. C

    Old(ish) Grundfos proportional pressure control circulator

    I'm trying to set up a Honeywell DU145 ABV with an ALPHA 15-60 130 (Model number 59526443) and work out the speed setting. The pump has one variable dial (no C1/2/3 ect). Grundfos support have no info on the pump as its from circa 2001, so unable to help. Its running 5 rads in a small 2 bed...
  19. S

    Grundfos Pump UPS3 Head

    Hi Guys, Got a knackered Grundfos UPS 15-60 130. Have a replacement Grundfos UPS3 15-50/65 130. Is the UPS3 pump head compatible with the UPS 15-60 body so I can just replace the pump head, or would I need to fit the UPS3 body as well? Thanks
  20. D

    Grundfos Default setting

    Hi everyone. Bit of a daft question but I’ve just had the pump replaced by the housing group where I live. They’ve fitted a Grundfos UPS3 15-50/65 and the fitter has left it on the default constant curve 3 which is a bit noisy and seems overpowered for the property, they’ve also snapped the...
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