I just had the spring loaded pipe clamp temperature probe go bad on mine (#556) today. That's the second one in less than a year. Fortunately it will be covered by warranty. Especially since a new one will cost me $215.00! I hope the next one lasts longer than a year. THAT'S AWFULLY EXPENSIVE FOR A TEMPERATURE SENSOR! It read 139 degrees strapped to the same pipe as my other sensor which read 74 degrees, 1/2 inch away.
I received the #556, with the first temperature probe on February 19, 2008. I ordered the second temperature probe about a month later. The first probe cost me about $140.00, now it is $215.00! That's inflation!
Fortunately I have a back up temperature probe.