Grunfos Alpha Pump Does the Trick

Paul Pollets

Yesterday we changed the original circ pump on our shop radiant system to a Grundfos Alpha variable speed pump.  The attached pics tell the story.  Before the changeout, we tested the original pump (Grundfos 15-58 3 speed) which was running at Speed 2 (.59amps or 69 watts) The system was calculated at 5' head so the original pump was pushing 10GPM.  The Alpha pump leveled out in 3 minutes at 14 watts and 2 GPM.  Changing the pump, including adding an outlet for the Alpha pump took 20 minutes. It helps to have isolation flanges...



I wrote an article in Contracting Business Magazine back in 1997 after returning from ISH detailing these pumps.  I'm glad they finally made it to N. America.  The energy savings by using these variable speed pumps has vast implications for hydronic design.

ChasMan

How does this compare..

To the Wilo? It is certainly a cheaper than the Wilo. It appears to have some additional features as well. I'm not big on that cord but I supose one can just lob the plug off and go into the panel. The installation instructions say not to modify the cord in any way. Is there a fuse in the plug or something?

Paul Pollets

The Plug

Cutting off the plug end will void the pump warranty. I've heard they may re-design the electrical to include a hard wiring option.



The Wilo Stratos  has similar performance curves.

bob_46

Alpha

Paul, What parameter is the Alpha monitoring ?

Devan

cord

I was told by Grundfos that you can cut the end of the cord. What they don't want you to do is not use the cord set pump end and rig in some other type of connector to the pump itself.Either way sweet pump, I just replaced a 15-58 in my house to an Alpha , drawing 13 watts for a full house of radiant.

Paul Pollets

ART shop

The shop (600SF) has 3 loops of 1/2" Uponor Multicor embedded in a a 4-6" concrete slab. The pump alternately displays watts being used and flow rate every 3 or 4 seconds in real time.

hot_rod

very accurate

the flow rate is accurate to within .5 gpm or 1 watt in any of the auto adapt positions. A little less accurate in fixed speed three. I have connected a flow meter to the circuit to check the actual flow rate to the read out.

wrigley

nice comparison, i did it with a taco and got better SAVINGs

had 5 zones of circs, 4 007 (85 watts each) and 1 0010 (120 W). replaced with 5 Grundfos Alphas and had TOTAL of 75W when ALL 5 were running. Surely e overrode the system to get all five running at once to simulate a COLD day and ALL people, all cicuits calling (baseboard/kickspace/convector system). but those are HUGE savings!

WOW!!!



Now, i do work for a rep that sells these things but if you don't believe me, ask dave martineau at bell simons in methuen as these are installed at his house! he is sharing kwh data as the heating season rolls into New england.

wrigley

by the way...

i saw a you tube post linked from this site a few weeks ago and had a video showing these savings, why did heating help take the post down????

as far as i see it, the truth spoke for itself.....???...??!?!?!

DanHolohan

I took it down

because it was an unfair and very misleading comparison of apples to oranges. The good folks at Grundfos agreed with me. The poster removed the video from YouTube.