bioler pump advice

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lotawood

Member
Dec 11, 2011
78
montana
I am getting a new to me boiler up and running. I found a leak in the pump that goes from the boiler to storage. That was with an air pressure check. The pump leaking is a B&G series 100. I'm thinking a seal kit, new impeller, flange gaskets, maybe their oil, coupler, body o-ring. About $47. Or I could get bearing assembly with impeller and flange gaskets for $112. This pump was installed in about 1983 on the old wood boiler system, a memco 100.
I saw a wilo 21 that was close to what the Dumont boiler manual suggested, 16 gpm on a 130k boiler. I have 4 feet of head on paper for my boiler to tank loop. So the wilo 21 3speed is on the light side, but not out of the question. It sure looks like a low amp draw. www.pexsupply.com/wilo-4090765-star-s-21fx-3-speed-cast-iron-star-series-circulator-1-12-hp
I ran across a taco pump. www.pexsupply.com/taco-007-vdtf5-007-variable-speed-delta-t-cast-iron-circulator-pump-115v
Would this be a good pump to put on a boiler to tank loop? There is a setting for reverse delta t. In other words, in reverse mode, the pump speeds up as the supply and return delta t gets higher. (water heats up, pump speeds up)
The three options I see are: 1) rebuild the B&G. 2) Taco 007 variable speed delta t pump 3) wilo 21 with maybe not enough flow at full burn.
The wilo is right at the curve for my calculations with out any room for error and at $72 it is a good price for new.
The taco seems like it will take care of over-pumping through the burn cycle when it is heating up and cooling down. I like simple, but efficient use of wire to water gets bonus points.
The B&G looks like the pump others are judged by, if your are under the curve. I like old school, but the amps are higher then other pumps. I am looking for low amps over decades of use. I would rebuild the 100 series with the seal kit. If it would be better to get the front end with a new bearing and housing along with the seal I would do that.
 
With the pump being that old & a rebuild kit almost the price of a new pump (or more), I'd get a new pump.

That Taco looks interesting with its ability to vary speed depending on delta T.

Another choice would be a Grundfos 15-58 three speed pump. It's around $86 on Pex Supply - and my laddomat loading unit came with a Grundfos 15-58 three speed pump built in. So if it's good enough for LK to used for storage loading with their laddomat unit, I'd call it a safe bet.
 
I can't say enough good things about the Grundfos 3 speed pumps. I'll never go with a single speed pump again even if I think I know exactly what flow rate I want.

I'd go Grundfos and never look back.
 
I did leave out a Grundfos choice I had. The alpha looks like a good choice for 16 GPM at 4 feet of head. It is priced the same as the 007 delta T pump. So two new pumps to chose from at $157. Or rebuild the pump cheap for about $50, but the old pump should probably have a new front end, impeller etc for $112.

I keep on seeing reviews for the B&G series 100 having decades long reliability, so that why I don't just kick it to the side. I was running this pump on the old boiler and there was some drips. It was so dirty behind the old boiler, I didn't know what was leaking.

That said, I am interested in a reverse delta T pump if is not getting too fancy.

I wish the alpha could do that type of delta. The alpha is a delta P, if I understand the terms correctly. An alpha on high speed gets me under the curve. The 15-58 is close, but it looks like I am over that curve.

For latter in the project, I do have an old 15-42 to use in the radiant loop. It looks like an alpha is better in that location if the 15-42F doesn't work out.
 
Anyone useing a newer B&G circ pump? My supplier was trying to sell me on them awhile back, but the "Made in China" sticker made me never give them another thought. Just curious, I know the old B&G stuff was cutting edge in design, and the famous Gil Gilson (wrote the book on pumping away) worked for B&G.

TS
 
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