Glowworm3 25r - Radiators Heat not coming on - temp shown briefly then nothing

[AndrewDJohnson]

Hi
With the above boiler - Glowworm3 25r , I just swapped out my controller (A Drayton LP241 for Wiser Hub - pin and holder compatible). It all seemed to work, but I had to change it back because of WiFi range issues. However, now that I've put my old controller back, the boiler won't come on when I want radiator heat! I can see that the display shows the temperature for about 2 secs - and acts as if the boiler WILL come on to provide heat, but it doesn't. The pump does come on though...

So, it's not the thermostat (which is fine) and it's not the controller... I wonder if boiler is "upset" as it's somehow detected a change in the controller.

Oh, the hot water side works fine!

Thanks for any info help or info!

Andrew

 

[AndrewDJohnson]

Update! I've found that the radiators get warm when the hot water is on... I presume this means it's something to do with the 3 position valve... Hmmm....