In most regions, a professional installer is not required to setup your ZEN thermostat but it is recommended. Before checking anything on your current system ensure that the mains power breaker is turned OFF.
The ZEN Thermostat is only compatible with low voltage systems, rated to 24VAC. The ZEN Thermostat will not work as a replacement for mains voltage thermostats which are typically 110-240VAC. If you are unsure about your type of system or suspect that it may be rated at 110 volts or higher, do not attempt to install your ZEN thermostat: please contact an HVAC professional to assist with your installation.