Honeywell ST9400C- setting help

[indus]

Hi
I'm sure I must be doing something really stupid. I'm trying to adjust the hot water settings. I want it to come on at 1200 am, at the moment it's set to come on at 0500am.

From 0500hrs if I press the setting minus button it won't go below 0300am. If I try and go the other way ie press 'plus' as soon as I get to 1000am it automatically goes from the on setting to off time.

Thanks

 

[CBW]

Have you consulted the manual? https://homecomfort-techlit.resideo.com/emeadocuments/uk07/st9000wired-50022737005-uk07r0812.pdf