Programming Drayton Digistat

[RichD1]

Just replaced my old controller and the new one seems to have different algorithms in the software than the old one. It switches heat off before the temp gets to the pre-set one and also switches on before the temp falls to the pre-set. I assume this is in an attempt to stop overshoot and keep a more even temperature.

My problem is that it only switches on for a short while during these sequences. I watched it this morning and the boiler hadn't been on for a while as most rads were cold. It switched on and then only stayed on for about 10 minutes and then switched off. The rads hardly got hot anywhere which must be wasting energy and money.

I'm sure I've read somewhere (not in the manual) that it is possible to reduce this cycling affect but I can't find it now. Does anyone know whether there are hidden settings in the Digistat and how to get into them and what settings can be adjusted.

Richard

 

[Steve Rawlings]

Yes, the predictive algorithm in the Digistat +3RF is riddled with bugs that causes the boiler to be 'off' when it should be heating; and 'on' when the room is above the set temperature. This causes mayhem at the boiler, with frequent heating on/heating off commands that prevent proper cycling (modulation) of modern boilers.

Bizarrely, these spurious on/off signals to the boiler also happens in 'manual' mode.

You could try setting Installer Options 12 and 13 to '1', but the best solution is to ditch the Drayton entirely and buy a proper thermostat. You'll save money in the long run.

 

[Steve Rawlings]

Also see:
https://www.diynot.com/diy/threads/drayton-digistat-3-accuracy-issue.210304/