I have a two-sided, natural gas gravity wall heater controlled by a low-voltage thermostat.
It is possible to replace the thermostat with a simple on/off Z-Wave relay switch of some sort? I can use existing temperature/humidity sensors in my unit to automate the switch.
@anndrewww As long as the relay switch does not have any voltage coming out of it, It will work, But keep in mind heating thermostats have a heat anticipator in them, It heats up the thermostat a little and fools the thermostat its a little warmer then it actually is, This is so the room don’t get too hot then too cool on cycles. If you use a relay you may find you need to have a different on/off temperature then you actually want.
You’re looking for a dry contact switch, the Sonoff SV looks like it’s what you want.
I’m considering something like that, I don’t want a thermostat with its own logic because all the “clever” part of heating should be in HA in my opinion. (besides it’s way more flexible and way less expensive to have 3 Xiaomi temperature sensors !)
But, Sonoff isn’t exactly what I’m looking for, as it needs MQTT and I wish I had a fully integrated to HA solution. Is someone aware of another solution ?
I know this is almost 2 years old, but figured if I came across this, others may do also.
The SOnOff SV is definitely not the device you want.
SOnOff is not a dry contact, it switches the incoming low voltage line which must be a DC voltage between 5 and 24volts.
SOnOff will do MQTT, but it’s not dry contact.
Best to do a DIY job using an ESP8266 and a relay board if you want to do what the OP wanted to achieve here. Many have done it DrZzs did a nice one, YouTube video is available if you search DrZzs thermostat. He mostly uses Tasmota firmware on the ESP8266 based D1 Mini.
The temperature will register differently as you will be using different sensors to pull temperature, but that would happen if you replace an old thermostat with a new one also.