Honeywell ST9100c heating towel rails randomly

[k4yla1987]

Hi,

We have a Honeywell St9100C timer fitted which controls the towel rail element of our heating system so there is no thermostat. However despite repeated attempts to program it, the towel rails are just on whenever they fancy it!
The Honeywell is fitted through our underfloor heating controller.
I’ve tried to do a bit of research but would like assurance that it’s wired correctly for the job intended. I’ve attached photos.
Any help appreciated

 

[k4yla1987]

Anyone???

 

[JohnD]

Are you lucky enough to have a nearby hot-water cylinder heated by your boiler?

 

[RandomGrinch]

All I can say with confidence, is that the ST9100C has been wired so that a call for heat will provide a switched live output onto the grey wire.
The wire is in the correct terminal, but where that grey wire is connected, and how the Hestmiser responds to it, is another story.

 

[k4yla1987]

Are you lucky enough to have a nearby hot-water cylinder heated by your boiler?

No unfortunately not, it’s a combi boiler.

 

[k4yla1987]

Also looks like it’s not run through the Heatmiser but straight to the boiler (Worcester Greenstar 40)

Thank you