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.