what does the sensor ohm out at room temp? If its around 1170 ohms or so, then its probably a standard oven sensor. Back in the day there was only one sensor for all of the erc ranges that I know of.Check out the sensor ohms and get back to us. a photo would be nice too if possible.
How about a Rinnai Continuum. I have installed many over the years, not a single clinker in the bunch. the gas supply line needs to be upsized to a 3/4 inch because they ramp up as high as 149000 btus.I usually use black iron but you can use the newer armorflex type products. It's also a a good opportunity to upgrade your existing gas lines in the home for future expansion. The difference in price is less than 400 dollars and the savings are immediate. zero standby loss. Call a few heating professionals in your area and get some free estimates. This is the best time of year for having something like this done as the heating guys are hungry as hell !
My average installed price is 12 to 1700 sheckles depending on the complexity of the installation.
Energy is simply too damn expensive to fool around with wasteful heating and cooling appliances anymore.
It is the cheapskate that pays the most. Also, there may be some rebates in your state( directly proportional to the number of greenie weenies in your statehouse.)