Pulsacoil ECO Stainless timer problem

I have a Pulsacoil ECO Stainless boiler which was installed a couple of years ago and is connected to a Nobo Orion 512 timer. I have a normal non-Economy 7 meter in the communal cupboard of a block of flats. The timer is set to turn the boiler on twice a day at 6am-9am and 6pm-9pm. It works fine in the morning but does not switch off after 9pm and stays on all night.

I have changed the times to only heat overnight from 3am-9am and it switched on/off ok. I also tested the timer during the day by changing the clock time to a couple of minutes before 9pm and intriguingly it switched off at 9pm as expected.

I know these boilers should ideally work off-peak, but surely the timer controls it at all times. My question is could the boiler be set somehow to override the timer in the evenings for off-peak use? It would be strange as you would expect it to go on after midnight. Or is the timer/receiver the issue? Again strange as they work normally in the morning and overnight, and also when I changed the clock time.

Check your manual

The timer should work the off peak heater.

What works the on peak heater? The same timer?

Check the timer is correct.

Check on over ride / manual that the heaters are working / have a supply.

If the off peak heater is not working. That could be a faulty rod stat.

Also the unit needs a supply to run the pump etc.

Mike