Worchester 24i problem

[Lee Woodward]

Hi,

I have a Worchester 24i combi boiler. I have hot water but my central heating wont work. When I turn the heating on the boiler make some clattering noises and a small leak starts from the heating out put.

Can some please help and advise me on what the problem may be.

 

[Gasguru]

Are we talking about a 24i RSF from late 90s with the grey lower controls panel?
Maybe pump seized?

 

[Lee Woodward]

I think so. It does have a grey control panel.

 

[Gasguru]

Looks like this...

https://www.elektroda.pl/rtvforum/topic3490384.html#gallery-1

Pumps the Bosch lump on the RHS...might be seized..easily checked.

 

[Lee Woodward]

That's the one. How would I go about checking this?

 

[Gasguru]

Turn off the power and the gas off at the meter.
Best to drop the system pressure to just above zero.
Hinge the controls panel down and cover the panel with cling film for protection.
Unscrew the large screw in the centre of the pump, it will dribble water.
With a 4mm flat bladed screwdriver check the impeller shaft is free to turn.
If so power up the boiler and run the heating and check the shaft turns.
If you place the screwdriver in the slot you can feel the torque as the pump starts and runs...a good pump should show plenty of turning force.

 

[Lee Woodward]

I have now done this and the pump impeller seems to turn fine but once I powered the boiler back up I could not feel the pump running and the boiler made the same noises then the ignition shut off.

 

[Gasguru]

I mentioned turning the gas off...if you continue to let the boiler fire up with no circulation in the heating circuit you run the risk of the overheat thermostat tripping and you will give yourself another problem (apart from stressing the heat exchanger).

If you're competent you could measure the voltage at the pump terminals to confirm...