Hot Water won't turn off - HP2 programmer

[Threepwood87]

Hi all

First of all thanks in advance for anyone who takes the time to read this and send a reply.

I have a British Gas HP2 programmer controlling my hot water/heating.

Recently, the controls on the left side of the panel for the hot water have stopped working. By that I mean, even when I set the programmer to "OFF" or "TIMED" the boiler still creates hot water constantly and won't turn off. I can hear the hot water being generated by the boiler and also the pilot light in the nearby box is lit, even when I switch the HP2 to OFF. Currently the only way to stop the hot water is to switch the entire boiler off at the mains.

Oddly, the HP2 programmer still works on the right side for the heating, and it switches it off and on as intended. Also, the buttons for the hot water still appear to work with the arrows showing as you push the function button, and even the green light activating when you switch it to "ON" (photo below).

Does anyone have any idea what the problem might be? And if the issue is with the HP2 programmer itself (which is odd as the Heating side does work), does that mean I need an electrician and not a plumber to assist?

Thanks again, and happy to answer any additional questions or send any photos.

Threepwood.