Knowledge is power my friend. Now you have the know how and you can see how easy it is. Next time do it yourself and sign in here and share, I think we have this sucker worked out. That probe gets brittle with age so watch it when you clean there at the end of the season - soft brushes and take care with that vacuum hose but you do need to clean the exhaust tube thoroughly. Slow and steady wins the race. I'm even thinking once a season change if you burn long and hard but perhaps that is a little extreme. At mouser.com I am sure this generic 1000 ohm thermistor can be bought much more cheaply. It's not even the cost it's the time it takes for Harman to get round to fix it. In a bad winter that may be a month or more and that can be agony if your sucking expensive HO or worse just cold. So become master of your own destiny. Another little DVC tip is pay attention to the fines drawer. The stove has particular needs but it's a great heat producer and is a very pretty lady - they are always the pricey ones.
Next year Harman are commissioning 100 new service trucks to cover the NE and they are all sitting there waiting to pounce on your problem and give you the worlds best service ... and then I woke up and the bed was wet........... HAHAHAHAHAHA ... Just a little private board joke, ignore this last part, as I'm just fkcin with you.
Have a warm winter.