Honeywell ST699 1 powering off after being switched on.

6 Oct 2009
Reaction score
United Kingdom
I have a Honeywell ST699 1 Day Classic Programmer controlling our Baxi Bermuda Inset 2 Manual Boiler Type 50/4 gas back boiler.

I have used only the hot water (HW) on twice a day timer over the summer. But not used the central heating (CH). I have recently changed to using the CH & HW and set the timer for HW & CH on twice a day.

Over the summer and up to this point I have been getting the HW as expected, so the timer was doing its job ok.

My problem is: After switching to CH & HW the timer keeps switching itself off (indicator lights and clock display go out and the usual audible switch off 'click' from boiler system). The only way to reset is when the timer is turned off at the mains but the timer switches off again after a short period of time.

Is my problem a fault that anyone on the forum recognises and can help with?

Is the problem likely to be a fault with the timer and if so is a replacement easy to install myself?

The boiler seems to be working fine. I did have to re-ignite the pilot light as it had gone out prior to me discovering my problem.

The boiler is due its annual service and a good clean as we live in a flat with a dog and fluff. But I don't think the problem is related to the boiler.

I don't want to spend too much time figuring out the problem if the easy solution is replacing the timer and job done.

Any help or advice gratefully received. Its getting cold here!

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