Bought a new honeywell model rth230b it says i have the availability to switch to celsius readings but does not say ho to do it does anyone know how. :confused:

The installation guide should have a table of setup options. Most honeywell thermostats with options require you to press and hold the "FAN" and "^" buttons simultaneously until the display changes to the setup menu. From there, the options and available selections are numbered, so you will need the table to find and change the option.