I have a vulcan ducted heating system, model no. 9255.
The control unit is displaying the room temp as 35C when it is actually 11C or less.
35C is the max temp possible. As the room temp is displayed at the max temp, the heating will not come on as it its thermostatically controlled.
I have tried resetting, restarting, removing and replacing the batteries, and resetting the identity code.
Turning the unit off for 10minutes or more results in the room temp reading decreasing.
I think the problem is with the units internal thermostat. Is it possible for this to overheat?

Only Vulcan I can find. Are you in the USA or Australia ?

Vulcan Radiator

I fixed this by replacing the batteries with new ones, even thought the display was not reading 'battery low'. I guess this should always be a first port of call.