Welcome, Guest. Please login or register.
Did you miss your activation email?

Username: Password:

Author Topic: Grundfos 15-58 now too small  (Read 2433 times)

Ridge

  • Training Wheels
  • *
  • Offline Offline
  • Posts: 38
    • View Profile
Grundfos 15-58 now too small
« on: August 13, 2016, 10:24:32 AM »

What would the next size pump be, looked at a 26-99 but that's like double the flow, would like something in middle, we added 2 zones last year for a total of 6 and now added another.
Logged

mlappin

  • Fabricator Extraordinaire
  • Global Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4140
  • OWF Brand: homebuilt, now HeatmasterSS
  • OWF Model: Martin Steel Works Gen 1 then, now a G200.
  • North Liberty, Indiana
    • View Profile
    • Altheatsolutions
Re: Grundfos 15-58 now too small
« Reply #1 on: August 13, 2016, 11:46:03 AM »

A three speed 26-99 running on low is roughly a step above a three speed 15-58 running on high.
Logged
Stihl 023
Stihl 362
Stihl 460
Sachs Dolmar 112 and 120
Homemade skid steer mounted splitter, 30" throat, 5" cylinder
Wood-Eze model 8100 firewood processor

HeatmasterSS dealer for Northern Indiana

RSI

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3100
  • OWF Brand: HeatMaster
  • OWF Model: G200 and B250
    • View Profile
    • RSI
Re: Grundfos 15-58 now too small
« Reply #2 on: August 13, 2016, 05:27:50 PM »

You could get something like a 26-96 but really no point not going with a 26-99 and running on a lower speed.
Logged

Ridge

  • Training Wheels
  • *
  • Offline Offline
  • Posts: 38
    • View Profile
Re: Grundfos 15-58 now too small
« Reply #3 on: August 13, 2016, 06:09:46 PM »

What is the power draw differance from the 15-58 (mine is a single speed) and a 26-99 on low?
Logged

RSI

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3100
  • OWF Brand: HeatMaster
  • OWF Model: G200 and B250
    • View Profile
    • RSI
Re: Grundfos 15-58 now too small
« Reply #4 on: August 13, 2016, 06:20:39 PM »

According to the ratings, a 15-58 is 87 watts on high and  26-99 is 150 on low and 197 on high.

You could just get another 15-58 and put it in series. Could probably run it on low or medium and get the same flow.
Logged

Ridge

  • Training Wheels
  • *
  • Offline Offline
  • Posts: 38
    • View Profile
Re: Grundfos 15-58 now too small
« Reply #5 on: August 14, 2016, 05:14:13 AM »

What about the alpha pump, it looks like it moves more gpm? And looks like it would use less power, with as many zones as we have the pump runs alot, always one needing heat
Logged

RSI

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3100
  • OWF Brand: HeatMaster
  • OWF Model: G200 and B250
    • View Profile
    • RSI
Re: Grundfos 15-58 now too small
« Reply #6 on: August 14, 2016, 11:42:24 AM »

The Alpha is just slightly smaller than a 15-58. You could use one of them in series with your existing pump.

You need to look at both head and GPM ratings.
Logged

mlappin

  • Fabricator Extraordinaire
  • Global Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4140
  • OWF Brand: homebuilt, now HeatmasterSS
  • OWF Model: Martin Steel Works Gen 1 then, now a G200.
  • North Liberty, Indiana
    • View Profile
    • Altheatsolutions
Re: Grundfos 15-58 now too small
« Reply #7 on: August 14, 2016, 07:25:28 PM »

My two cents, step up to the 26-99 and keep your 15-58 in case of a emergency, the slight step up in watts used shouldn’t break the bank.

Another good option, and I wish Grundfos would offer it, put replace the 15-58 with a Taco Delta T pump then no matter how many zones are calling for heat, you can always keep your Delta T where you want it. I’m running one for my house at the moment, heat load can very wildly, any combination of DHW, heat, snow melt, or all three at the same times can drastically vary how much flow is actually required, so far the Taco Delta T has worked neater than a skeeters peter.
« Last Edit: August 14, 2016, 07:34:29 PM by mlappin »
Logged
Stihl 023
Stihl 362
Stihl 460
Sachs Dolmar 112 and 120
Homemade skid steer mounted splitter, 30" throat, 5" cylinder
Wood-Eze model 8100 firewood processor

HeatmasterSS dealer for Northern Indiana

juddspaintballs

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 640
    • View Profile
Re: Grundfos 15-58 now too small
« Reply #8 on: August 18, 2016, 06:48:07 PM »

I'm running a 26-99 on low.  I don't notice much difference in my electric bill in the winter.  It is more flow than I need right now, but it's what I had and it works.
Logged