Help with pump

[timfearn]

I have a Potterton Netaheat Profile 50e boiler, and the circulation pump appears to have got stuck due to the heating not being used since March/April time. The upstairs rads are hot, but not the downstairs, and the boiler is only coming on for short bursts, so I'm pretty sure it's the pump.

I've removed the facia plate from the boiler, located the pump and I know I need to check if the impeller is turning or not. There's a plate on the front of the pump with a pretty large screw in it - do I take this off to get access to the impeller? And do I need to keep the power on while doing this so I can make sure it actually works? I assume so....

Any help or step-by-step instructions on what to do next would be much appreciated as I'm a complete novice with boilers!

[sonray ltd]

where did you say you found the pump ?

[timfearn]

Hi - it's smack in the middle of the lower part of the boiler, right next to the circuit boards.

[sonray ltd]

have your got a pic of this.

[grahamep]

Word of advice Tim - don't touch that big screw until you've posted the picture.