Central Heating/Pump Question

13 Dec 2008
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United Kingdom
I live in a 14 year old 4 bedroom house fitted with 13 radiators, a Grundfos Selectric 15/50 central heating pump & have 3 problems that could all be connected:

1) The 2 radiators in the living room don’t get very hot unless I put the central heating pump on speed 3.
2) When the central heating pump is on speed 3 it is quite noisy. It doesn’t knock or grind but there is quite a loud humming noise.
3) Even when the central heating is off, the pump still appears to be running.

Are these signs of the pump being on the way out? If this is the case should I replace the pump with a slightly more powerful one, perhaps the 15/60 version?

Many thanks
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wired up wrong in any case

humm is vibration, try to fix the pipes more firmly near the pump
humming could be age also... depends whos listening and describing the noise. id also expect the pump on 3 in that size system. if its alsways been fine on setting 2 id suspect the pump is wearing out. unless you also done ddecoratingn upstair s and turned rads on and off it could also just need balancing. worst comes to worst it could need a flush.

id say balance, the replace pump then flush in that order.
pump(circulator to give it proper name) could be also doing the hot water system s or y plan!
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Pump running all the time is it recent or always done it depending on what boiler it maybe a fault within that but the usual cause is a stuck microswitch in the motorised valve.

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