What is the lowest set temperature on the ITC-308 WIFI?

I am attempting to use this unit to run the furnace in my garage. How low am I able to set the temperature? I see the probe is capable of -40F but I’m curious how low the unit can go. Is it fully adjustable on the App? Am i able to plug in my furnace to the heat plug and set the unit to 25F and it will turn on and off accordingly?

Hello,
The probe temperature range of ITC-308WIFI is -40~100°C/-40~212°F, but please note that the probe and wire cannot directly touch the fire.
The temperature range that the ITC-308WIFI body can withstand is -20~ 60 °C / -4~ 140 °F, and the humidity is 20~85% (No Condensate)
Please refer to the principle of ITC-308WIFI: