If Child Lock is enabled, whenever a button is pressed, Child Lock will appear at the bottom of the screen.

To enable or disable Child Lock Hold both the BACK button and the DIAL down together at the same time for three seconds.

School Lock is a feature built into the heater but not advertised and we do not actively support it or encourage its use.

The reason - whilst the diagnostic screens are accessable whilst in child lock, no settings can be changed! Once School Lock is set, no settings can be altered or viewed.

School Lock can only be altered by a qualified person under the permission of the owner of the heater (ie; a school caretaker).

School Lock is ON by placing a jumper over the bottom two pins of the header marked SCHOOL LOCK (or leaving the jumper OFF). 

School Lock is OFF by placing the jumper over the top two pins of the SCHOOL LOCK header (default factory position).

To enable or disable Child Lock, the qualified person has to safely isolate both mains supplies, remove the bottom grill, side panels & outer front panel, then move the jumper. Reassemble heater & power up.

If none of the above are activated the try switching the heater off, then back on at the wall. Are the controls now responsive?

If this does not solve the issue, an engineer will need to attend with a replacement User Interface (needs to be the right UI part number for the model & size of heater).