How to reset a honeywell cm921 - Honeywell Programmable Thermostat Heater

SOURCE: Honeywell CM921 Showing room temp at -24 degrees, How do I reset?

Heya this is a manufacturing fault from honeywell them selves when it comes up -24 basically it needs to be replaced there is no way around in if you get in touch with honeywell they are generally good about it also if you provide them with the date code and model code they will be greatfull as it seems they have sent out a "bad batch". you locate this by:

A) Move the slide in to the off position
B) Press and hold i for 5 seconds
C) Unit will enter settings mode
D) Press and hold the i button and the + and ¿ button together
E) The unit will hold the relay on for 5 minutes and you can view by pressing the down arrow twice for model id/date code (ww/yy)

I hope this helps

SOURCE: Honeywell CM921 Showing room temp at -24 degrees, How do I reset?

honeywell cm921 problem with red light flashing tenp not controling boiler can any one hel