Thermostat for forced-air in wall heater

I need to get an OpenHAB compatible thermostat (Z-wave or WiFi preferred) to manage an in-wall forced-air heater. This is a 240V unit with a heater and fan in one box. I looked at the Stelpro STZW402, but that is not compatible with that type of heater. They do have a Zigbee version, which sucks since I don’t have any Zigbee stuff and don’t want to add another protocol.

Any idea why the STZW402 is not compatible with the forced-air heaters?

Any other suggestions for this application?

It probably doesn’t have support for the fan control wire. Usually, forced air installations have at least six wires while fanless heaters will have one less.

It’s just a guess.

I would imagine that any thermostat for central air (Honeywell, Nest, Echobee) should work but without knowing the specifics of your heater I wouldn’t know. And I wouldn’t trust my advice anyway.

I emailed Stelpro support, and they said that the Z-wave unit controls the heater with PWM (rapid on and off cycles), which is ok for baseboard heaters, but not good for the units with fans. The Zigbee unit runs longer cycles.

I can’t use an Ecobee as this is a line voltage heater, not 24V control. It is a simple 2-wire connection. On or off.