honeywell st699

We have a back boiler controlled by a Honeywell ST699 programmer (CH & HW). The CH has been switched off all summer, with the HW continuing to be run as normal. I've just tried sliding the CH slider switch to turn on the CH, and it's tripping the RCD. I turned off the CH slider, reset the...

Hi, first time poster with relatively little knowledge of central heating controllers here ! I've got a Honeywell ST699 controller which controls a Valliant ecoTec Plus 831 combi boiler. The Honeywell is left over from when we had our old boiler and a hot water tank. As the Valliant is a...