I bought 3 digital thermometers with probes but they all "popped" and the thermocouple blew out of their metal capsules. I was only able to save one of them but it reads way off now. I blew them up every time that I started a new fire with a kindling fire first. I was going to be able to monitor the temp of my boiler in the cellar from right in my living room-but that didn't work out. I bought them from Cole-palmer. I guess they would work if you pulled them out during a startup process. I was going to use 1 in the stack of the Hitzer, 1 in the boiler stack that I could read upstairs , and 1 in the boiler stack to be read at the boiler. Would have been pretty handy. But, I think I have a good handle on the coal burning process now and I really don't need no steenkin thermometers.