Circulator Power Consumption

Steamhead (in transit)

you should be able to pump less water. These have zone valves on them, right? I've pumped similar systems with Grundfos 15-42 or Taco 005 or 007 single-speed circs, listed in order of increasing capacity, selection being made according to loop length. The Grundfos 15-58 3-speed mentioned above is a good choice if you like to experiment. All four units would draw less than the Taco 0010.

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jim post

watt's up

We have recently begun to trim our electrical consumption. We are down to about 2Kwhs overnight after unplugging TV, Computer, Refrig and any other obvious potential power users. We have a couple of circulators on our bb heating system. One little red B&G pump that runs continously from our Tarm Wood Boiler and one B&G Series 100 that cycles on and off as our 3 BB zones call for heat. The draft fan on the Tarm also cycles on and off as needed. How can I determine if 2 kwhs is reasonable for my heating system consumption overnight? Thanks for any insight you care to share.

jp

Brad White

All aboard..... Night Train!

If by overnight you mean say the 8 hours between 10 PM and 6 AM and you use 2.0 kWH, (2,000 Wasss-uuuuppps), that is 250 Watts per hour.

If your circulators draw 75 watts each (a reasonable guess, could be 85 or 100 or even 45) that leaves another 100 Watts intermittent for the draft fan. (Just a guess, have not looked it up). That is probably not 100 Watts, probably more like 150 or 200 but intermittent. Check the nameplate Wattage of each (or amperage multiplied by voltage to get Watts if not otherwise listed) and figure that against your assumed run time over night.

Overall it does not seem unreasonable but it does underscore the costs of moving water.

Uni R_2

Watts Up

There's a 190 - 200 watt draw for the B&G Series 100 when it's running. A Grundfos 15-58 would draw far less (60, 80 or 87 watts depending on the speed). There would also be some draw for the zone and boiler controls - although there is not much you can do there to do reduce that.

Boilerpro_5

That series 100 is energy hungry....

as suggested, a little Grundfos UP 58 fc pump or equvilant would cut that power down. If you really want to cut your power, look at the Wilo brand ECM motor pumps. They could replace both pumps and probalby get your peak use for pumps down to 50 or 60 watts.

Boilerpro

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Steamhead (in transit)

But

if you need the B&G 100's capacity, try the Taco 0010. It's still 109 watts, but that's better than the B&G 100.

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jim post

I'm bummin'

That circulator load is gonna prevent us from getting our elec consumption as low as we were hoping. Thanks for info...I had assumed the circulators were more efficient than that. The little red pump is labeled 125 Watts. The LP boiler is 40 years old and the B&G 100 is probably original. I've swapped out the motor mounts and coupling at least once. I'm not sure I "need" the B&G 100, but what determines the "need"? It serves 3 zones of 3/4" bb.

JP

hot_rod

Why does

the circ on the Tarm run continously? You should be able to cycle that circ with a heat or storage tank call? That would save some power.

I'd bet both circs could be replaced with a 15-58 on speed 2, possibly speed 1 on the baseboard loops.

There is not much pressure drop through a Tarm speed 1 would provide 8 gpm at a couple feet of head.

It all depends on how you have things piped.

hot rod

jim post

Tarm Piping

No Storage, so the Tarm is fired 3 times a day varying the fire size to meet the expected 8hr heating load. The pump on the tarm is set up to run anytime the water temp is 140 or more...pretty much always with our firing schedule. We have a side arm heat exchanger on our electric H2O heater which dropped our usage 5Kwhs...but these circs are killing us...probably an equivalent load to our electric water heater daily. Ouch.

Thanks for the info.

jp

hot_rod

If you can get your hands on a...

Grundfos Alpha Pro prototype, maybe check with the local Grundfos rep, they are trying to get some in the field for testing.

I have 3 installed and find they consume about 1/2 the power of the typical wet rotor circs. Generally between 17- 20 W is what I see on the display.

You might pump that Tarm with 10- 15W!

Laing and Wilo have or will have their ECM circs on the shelves soon.

hot rod