Worcester 24CDI RSF Gas Combi Boiler

19 Oct 2005
Reaction score
United Kingdom

I de-pressurised my boiler, removed a radiator and then replaced the radiator valves.
I did not replace the radiator since I was going to decorate the wall where it was located. I closed the radiator valves off and then pressurised the boiler, unfortunately one of the valves was faulty and I had loss of water.

I sorted the valve out and then put the pressure back, but now, if I turn the hot water tap on, the DHW demand light comes on and the flame indicator light comes on, but the flame indicator light goes out after 5 seconds and we have no hot water.
The boiler makes a whirring noise when it fires up, does anyone have any ideas, please?


Sponsored Links
Does the boiler fire up at all ?
Has the boiler locked out ?.......Press the reset button
Check pump han't stuck for some reason whilst boiler drained. Remove large screw head on front and put screwdiver in and see if you can turn it.
Sponsored Links
Give the aav on top of the boiler a gentle(ish) tap should let the air out.

I have just picked up your replies tonight and I will give them a go tomorrow.

Here is some more specific information that I obtained today-
When hot water tap on - the boiler certainly fires up and starts to heat the water but then the burner goes out.
The pump is making the whirring noise and becomes red hot to the touch.

I will try out your suggestions, and come back with my results.



Yes indeed it was an airlock, air released from the vent and all working fine now.
I found that the auto air lock vent had sealed itself due to a build up of limescale. - is this condition on the vent normal?

On a seperate note, is there a correct procedure to follow when removing a radiator?
-should I do the following\ de-pressurised the system - turn off the CH flow and return valves at the appliance - turn off the radiator valves - remove\replace radiator - turn radiator valves on - open CH flow and return valves - re-pressurised the system

thanks for all your advice, very much appreciated.

best regards

In my experience the AAV's on these boilers are quite problematical. I have replaced several with a more robust unit.

If just removing a radiator (no pipework mods) then you don't need to de-pressurise the system or turn off the boiler valves. Just turn off the rad valves, drain rad, remove rad, replace rad, turn on rad valves, vent rad, adjust pressure in system.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links