When I test a gas dryer, I m testing it on propane fuel since I dont have a natural gas line in my garage. I do it to insure the dryer is heating before I turn it loose. I currently dont have a means of measuring the temperature at the vent pipe coming out the back of the dryer. Is there a reliable but fairly low cost device available for me to buy for the measurement of the outlet temp ? A thermocouple used in a lab would be nice but probably a lot of $ to buy. Also if I checked the t-stats for function when it is cycling on and off what kind of time interval should I expect to see for either Natural gas or propane ? This is getting to be very interesting. The dryer ID tag usually states it is designed to run for instance, Natural gas at a certain delivery pressure and delivering 22,000 BTU/hour. Some dryers are made to deliver more or less BTU/hour and other old ones deliver 20,000 BTU/hour. The gas pressure to do this varies and is stated in w/c of 3 inches or 3.5 inches or other numbers. I have never witnessed a test using these numbers. My new Speed Queen dryer in my house runs on natural gas and the ID tag states it produces 22,500 BTU/hour at a pressure of 3.5 inches W/C. I have never timed the on and off times for it when it is drying clothes but I do run it on the automatic cycle and not the timed cycle. Next load of clothes I dry I will try to do that for a comparison.