I am not using room temperature infact, I have put the fan inside a box so that it "self heats" and it is running in 60C, that is as hot as I can get it. I am noticing lots of brush wear already at 85C case temperature so I'm in no position to go higher as I'd rather not start a fire. The temperature of the stat you refer to is the hot water in the engine, this is not neccesarily the ambient temperature. The engineer told me to run the motor until 80C (case temp) I think we usually calculate an ambient of 80C, of course the cardboard box it is in don't like heat much !