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Viessmann pump replacement

Harman009
Harman009 Member Posts: 8
Hey guys I have a viessmann 100 vitodens b1ha

The pump within the boiler grundfos ups 15-78 has failed which is kinda odd. Checking everything and don't know how it could just stop working. No garbage in pipes or nothing. I don't think its air because it worked fine until it didnt? 

I could simply replace the head as I could've gotten a defective unit. But I figured I would upgrade it because the boilers circ is almost always on. (Still working out ODR setpoint and curve) 

I have a grundfos alpha 2, and noticed it sips power compared to the ups 15 78.

Could I find an alpha 2 head and install it within the ups 15 78 body? The body is different but it has the same 4 screws to remove the pump. 

I'm having trouble finding single parts so I may just have to get the whole alpha 2 pump and then use the head from it. (IF it's compatible)

Some info about my system is a 3 story house with floor heat. The boiler also heats an 79 gallon indirect. 

Comments

  • Sometimes those Grundfos pumps have a different electrical plug.

    Unusual for the pump to go bad. Can you meter how many amps it's drawing? Maybe see if it even has any power going to it. It may not be the pump.

    I would only use the same pump as a replacement.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
  • hot_rod
    hot_rod Member Posts: 18,195
    I would remove it, power it up with a cord, see if it spins

    The 15-78 is an OEM pump, I think it is still available, NTI still uses it. You can switch just the powerhead

    If you can find the 15-78 curve deep in the Grundfos website, a 15-58 speed 3 may be close

    In Grundfos terminology the 15 is the ID of the inlet opening, the second number is shutoff head in metric units

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Harman009
    Harman009 Member Posts: 8
    I don't have an amp meter but a simple test light lol. 

    There is voltage to the head, I'm not sure if I can test the capacitor somehow but it isn't spinning or making any sound at all. It's like theres a break in the connection goinf to the actually motor internally

    I figured instead of replacing it with the same style, I could give it an upgrade. 
  • hot_rod
    hot_rod Member Posts: 18,195
    Check and see the voltage on the pump, early Viessmanns 
    were 230 V and had step down transformers
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hot_rod
    hot_rod Member Posts: 18,195
    It’s a fairly high head circ, probably to work the plate HX for DHW. It runs on speed 3
    You would need to find a union body ECM to fit that spacing, possibly a Alpha 2 26-99
    Not so easy to find union body circs in the US unless it is an OEM replacement

    Plenty if online suppliers for that 15-78, and a wide price range!
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Harman009
    Harman009 Member Posts: 8
    Thank you guys! I replaced the pump with another grundfos ups 15 series pump