The Circulator Experiment, Continued (Steamhead)_

Steamhead

that I've been trying out different circulator capacities to see what effect they have on a gravity-converted hot water system. I have concluded that it doesn't pay to go much below the capacities in the chart (see http://www.heatinghelp.com/newsletter.cfm?Id=125) since doing so may cause inadequate circulation at the ends of the system on mild days (yes, we actually have had a few mild, 50-degree days in Baltimore in the past week or so). And we know that overpumping any system will impair the heat transfer.

Here are the specifics:

System capacity: 545 square feet EDR

Boiler: Burnham V-14 down-fired to 0.75 GPH

Inside temp: 62 degrees

Capacity of B&G NRF-9 at 3.5 feet of head: 7 GPM

GPM per square foot EDR using B&G NRF-9: 0.013

Capacity of TACO 005 at 3.5 feet of head: 15 GPM

GPM per square foot EDR using TACO 005: 0.027

Capacity of original B&G 100 at 3.5 feet of head: 27 GPM

GPM per square foot EDR using B&G 100: 0.049

GPM per square foot EDR recommended in 1940 B&G Handbook: 0.023 (from calculations)

GPM needed for 545 square feet EDR based on B&G's flow recommendation: 12.5

The 005 is slightly over the recommended flow, but not by much. But the NRF-9 is way under- by almost 50 percent, and the original B&G 100 is over twice as big as needed. The 005 hit the sweet spot on this system.

All this effort to prove that the old B&G Handbook was spot-on!

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[Deleted User]

and to think i got a copy

of the b&g handbook on ebay for 5 dollars from someone who didn't know what they had. i sliped a copy of your chart into the book at the appropriate page cause yours is easier to read than theirs. hope to put it to use someday.

Steamhead

I have three versions-

1940, 1949 and 1954. There are more and bigger diagrams in the newer ones. But I almost threw 1954 in the fire cause it mentioned converting steam systems to hot water, which I have never agreed with!

Thanks for the kind words on the chart. That's why I put it together- to be used.

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Boilerpro_3

Say, Steamhead....Intermitant or continuous circ?

And did you try balancing the rads with the smaller pump? Also, how close is the boiler capacity to the design heat load? The closer it is, the longer the pump run time if you are running it intermittantly. I'd expect continuous circulation would probably more closely resemble the flow of the original gravity system and I bet that smaller circ would work then. Of course, it would be real nice to add TRV's at this point. If I remember right, B&G's formula is to calculate the radiation output at 150 btu/sq ft (180F), assume a 20F delta tee and multiple that flow amount by 50% or....Just figure the flow rate of 150 btu/sq ft radiation at a 13.3F delta tee.

Boilerpro

Steamhead

Intermittent for now

which around here has more real-world application than continuous. But I'm not getting rid of the NRF-9, the next part of the experiment will be constant-circ with reset.

I still haven't gotten around to running a heat-loss on this house, but I think the current boiler configuration is rather close to the load. I had some nice long run-times with single-digit outdoor temps.

See you at Wetstock, BP!

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