I have a Harman P61. I have had this stove for about 5 years now and it has worked great until this year. Every now and then it wont heat up, even when the room cools off. I have tried increasing the heat pot, changing from stove temp to room temp, moving the room temp sensor, nothing seems to make a difference. Anybody have any suggestions? It was -25F last night and only 55F in the house when I got up. The wife is starting to get a little grumpy about it!