One question for you:
What do PTC sensors as this one KTY83-110 (datasheet here: http://www.datasheetcatalog.org/datasheet/philips/KTY83_SERIES_5.pdf) do when the measured temperature exceeds the one specified in the datasheet?
In this case it is 175 degrees celsius, the temperature I would measure might go well over 200 degrees celsius.
Will it still return a reading? Will it smoke or will it blow?