Non-responsive circulator

Sam in NY

I have a 50-plus year old Capitol boiler that has been maintained very well. Heating season is here and my attempts to get the water moving have failed. The boiler fires fine when called by the thermostat and gets up to pressure. But there's a faint electrical buzz (like the sound a transformer makes) coming from the circulator but no moving water. The noise is not coming from the transformer in the basement ceiling. I've bled, purged, etc. Anything else I should try before calling a contractor to have the circulator replaced? Thanks for your ideas.

Steve Levine

Look for a way

to manually spin the circulator shaft. It may be slightly seized due to dirt, etc., and that may help it start. If the shaft is not exposed, there may be a cap on the end that will reveal a screw slot to turn it, or you may see a slot without removing anything.

Alan(CaliforniaRadiant)Forbes

Sometimes all it takes

is a good whack....not straight on with a hammer, though.

I put a piece of 2x4 on the end of the motor housing (opposite the volute) and then hit it with the hammer; not hard, just a sharp "whack".

I've seen motors get stuck on Taco (brand new) and Grundfos circulators.

If a couple of whacks don't do it, call your friendly contractor.

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Steve Miller

circulator

first check if the pump is getting 120v, if it is, use an allen wrench and remove the cartridge from the pump body and spin the impeller and if it spins freely, turn on the power briefly and see if it spins. If it doesn't, replace it.

Duncan_2

One other thing to try...

Mmmm-hmmmm! Motor hums like a transformer, but doesn't spin, probably gets hot to the touch: classic symptoms of a bad capacitor.

It's a long shot - it's a much more common problem for it to sieze in the off season. But if it spins freely, has good line voltage, and hums like you say, it might be the capacitor.

Get the capacitor tested at a local electronics shop if you don't have a spare cap to try on it.

J.C.A.

How big( what size/model)is this thing?

Sam in NY

The model was a Grundfos and one good whack did the trick. Thanks for all the info everyone.