Ethernet and power

Needless to say that connecting this IP thermostat needs an Ethernet connection nearby. Fortunately i have a 1Gbps switch only 3 meters away from the place where the thermostat will be placed. The thermostat also needs 24V DC power to operate. POE (Power Over Ethernet) is being used to power the NT20e. An EPA-20 can be used to inject the power into the Ethernet cable that goes to the thermostat:

Proliphix EPA-20

The EPA-20 is capable of powering 2 devices (not necessarily being Proliphix thermostats).

Dry testing

Before connecting the thermostat to my central heating, i decided to do some ‘dry’ tests first: connecting the Ethernet cable and power, but not the 2 wires that go to the central heating. I attached a multimeter to the connections i thought were the right ones for the combination of my central heating (Remeha Calenta) and the NT20e. My guess was i had to use the connections labeled RH and W1, so i monitored what was happening on these 2 connections when the relay switched. I tested voltage and resistance; and as i expected, no voltage is applied and resistance was either 0 or infinite; exactly the behavior i expected (and need).

Proliphix NT20e back plate

Back side of the NT20e thermostat

The thermostat is ready to be used, but first: testing the interface to my Home Automation system with the thermostat still in the office! (will save me a lot of running from office to living and back again while testing)