Central heating not coming on

[Stu999]

Hi

I hope someone can help.
Suddenly this morning my central heating has stopped working.
It worked last night.
I have checked the thermostat and is talking to control unit ok.
I have a grundfos alpha pump which has power, but that all it says, it doesn't pump anything through.
I have opened the pump to check it is not jammed and all is clear.
I am at a loss as to what it could be.
Does anyone have any checks I could do to determine the fault.
Many thanks

 

[twgas]

Have you checked that you have a boiler?

 

[easyflow]

System boiler or combi ?
Power to pump dosnt mean its working, any slight vibration or noise at pump ?

 

[Stu999]

System boiler or combi ?
Power to pump dosnt mean its working, any slight vibration or noise at pump ?

 

[Stu999]

System boiler or combi ?
Power to pump dosnt mean its working, any slight vibration or noise at pump ?

System boiler, pump comes on, lights up but no noise or vibration.

 

[easyflow]

Impeller stuck, give the pump a tap with a small rubber mallet or toffee hammer, may free it if not new pump.

 

[HERTS P&D]

Spin the impeller with a screw driver and see if it starts - have the heating turned on.

Andy

 

[Stu999]

Spin the impeller with a screw driver and see if it starts - have the heating turned on.

Andy

No acces to the impeller as it is a grundfos alpha 2 which has a digital display on front.
Could a blocked system or air lock in the system.

 

[Stu999]

Spin the impeller with a screw driver and see if it starts - have the heating turned on.

Andy

No acces to the impeller as it is a grundfos alpha 2 which has a digital display on front.
Could a blocked system or air lock in the system.

No acces to the impeller as it is a grundfos alpha 2 which has a digital display on front.
Could a blocked system or air lock in the system course this.

 

[bolshy]

Sorry, but the post from twgas made me chuckle. It's unlikely you've formed an overnight blockage. Air would generally make a lot of noise, pump whining and very hot. Silly question, but does the boiler fire up? If it does, is there a lot of banging?

 

[Stu999]

Sorry, but the post from twgas made me chuckle. It's unlikely you've formed an overnight blockage. Air would generally make a lot of noise, pump whining and very hot. Silly question, but does the boiler fire up? If it does, is there a lot of banging?

Yes, I do have a boiler haha.
There is no hot water or heating, boiler comes on and gets hot.
Lots of knocking this morning as we only had hot water turned on as thougt that was working.
Pump not hot, lukewarm but boiler hot.

 

[bolshy]

I have to say it's quite possible your pump has power, but isn't circulating, as easygas posted. It could possibly be a blockage, but I think this is much less likely. Is it a sealed system?

 

[Stu999]

I have to say it's quite possible your pump has power, but isn't circulating, as easygas posted. It could possibly be a blockage, but I think this is much less likely. Is it a sealed system?

Yes It is a sealed system, nothing circulating round the system. No noise from the pump.

 

[HERTS P&D]

You need a new pump.

Andy