Heating/Hot controller water problem

[decon]

My heating and hot water are on a timer. The heating works every day as per the timer settings, but the hot water is intermittent. Sometimes i'll have hot water for a week then it just doesn't work in the morning one day then maybe the afternoon a few days later {no rhyme or reason). It also wony work usung the bost option when the heating is on.

The two port valves do not seem to be the problem.

Since the hot weather has arrived. I have turned the heating off on the timer and now the hot water works everyday as per the timer settings.

I have a S plan system with a Drayton LP112 timer. with the time the same for for heating and hot water am and pm operation.

Could it be the Drayton controller or maybe the cylinder stat? has anyone encounter this problem before?
Thanks for looking.

 

[CBW]

It could be the programmer, but it could also be a loose wire/connection - I’d be looking at that first.

 

[MrTherm]

Experiment, try to stagger your programmer channel timings by the smallest allowed time increment with C/H either leading or trailing.

Good luck

 

[oilhead]

LP112 is only single channel so you cant separate switching times. If it is an S plan, then it has to be either a sticky zone valve on the DHW, or a faulty cylinder stat, (or a loose connection)

 

[CBW]

LP112 is only single channel so you cant separate switching times.

You sure about that?

 

[ianmcd]

LP112 is only single channel so you cant separate switching times. If it is an S plan, then it has to be either a sticky zone valve on the DHW, or a faulty cylinder stat, (or a loose connection)

LP112 is dual channel that is what the 2 means, LP111 is the single channel