Honeywell CM67 Thermostat Problem???

Hi all,

Just a quick question I have a Honeywell CM67 Thermostat connected to a Vokera Linea boiler (cant remember the model but I think its 75).
After using the program function on the thermostat and selecting a temperature for any day or time range the slide switch is moved from prog to auto. If required the boiler will fire up to the reach the requested temprature. However if it is required to increase the temp then this only happens for a approx 5 seconds and then the flame light on the thermostat will go off even if the required temperature has not been obtained. If I manually increase the temperature using the temp button whilst in auto mode the flame light remains on and required temperature is obtained.

Any ideas, is my thermostat faulty or does it need some kind of manual reset??

Thanks in advance for your help!

The temperature sensors are pretty sensitive, so warm hands and breath make the temperature rise noticeably to it.
Also you might have an Optimum Start model, with it turned on, which means it thinks it knows better than you do exactly when to turn the boiler on

I did think it might be warm hands/air but even after leaving the unit for a while there is no change in temperature. Come to think of it the temp reading hardly changes
How would I know if I had the optimum start model?

You would know if you had opt start as you woiuld have specified when you purchased as its a slighlty different model and slightly more expensive.

What temps and times are you setting and what does the temp on the display show when it switches off?

I would reset to factory defaults and start again, also remove the battery and leave for a while.