Central heating flow/pump diagnosis

[Blue_Manc]

My house is split into two - being an older part and an extension.

My CH is warming the old part of the house that houses the boiler, but the new part takes an age for rads to warm.

My thought was is the pump not working, took bleed nut off and with a small screwdriver it spins freely. When pump on settings 1 or 2 I can hear no flow from it at all. On setting 3 I can hear a faint trickle and a nice humm as the motor works. Would the pump be he likely suspect?

 

[Dan Robinson]

Or a rubbish but of plumbing for your extension.

 

[Blue_Manc]

Thanks for the insight and advice.

Anyone else have some useful thoughts?

 

[Dan Robinson]

How about giving us some practical information on which to base a theory.

Does the pump shaft spin on the lower speeds?