Heating no circulation

Mar 27, 2019 Last reply: 7 years ago 22 Replies

We have just changed a pump. Though it would spin much of the time, it appears there was a 'flat spot' on it from which, if it came to rest on that, it could not restart.

If it's a grundfos pump they occasionally shear the shaft and while the end of the shaft under the top plug spins the impeller doesn't. Don't know what make of motorised valve you have but seizure of the spindle can and does a happen. Also some models permit removal of the top plate without removal from the pipework. Just beware losing the o ring seal.

that 2nd bit's handy to know!

NT

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