After 14 months of use with the combustion blower running all the time the Harman Co. has come through for me. I had a Harman rep come to look at my boiler a couple of weeks ago to find out why the burnpot was developing a bubble on the surface above the igniter. It took him all of 2 min. after looking at it to tell me this was not the first one he had seen do this. The cause was from the igniter being on to long a period of time after the pellets ignited. The fix is to replace the controller which has a newer program installed in it, turns the igniter off when the ESP senses 180 degree exhaust temp. The replacement controller is the same one that is used in the new Hydroflex 60 boiler. Time will tell if this will stop the bubble from forming but.......... this new contrller DOES SHUT DOWN the combustion blower about 31 min. after the status light goes out (boiler reaches high temp setting). I think any PB105 manufactured after Sept. or Oct. of 2008 has the new controller installed. The old boiler controller part # 3-20-05630A which was in my boiler was replaced with the new part # 3-20-06143A.
