Harman PB 105 troubleshooting questions

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New Member
Feb 4, 2022
My Boiler is 7 yrs old, I clean every week and burn about 200 bags of pellets per year. The problem began when it would start on auto ignition, the ignitor would stay on and feed pellets so that they overflowed the burn cup. When I would reset by cycling power the status light blinks once (1). I read that one blink is a board error and should be replaced. I replaced the board and the burnt ignitor (measured open) with new units. My new ignitor ran about 1/2 hr total (compressor works fine) and now measures open. So now I tried to start in manual as per book. Book says pellets won't feed till ESP reaches 170F but the water is getting heated slowly and the ohms of red wired ESP is 1100 ohms. There is no blinking lights on reset. Dip switches are set same as old board which are (1=on, 0=off): 01101010. I seem to be running out of options but I am leaning towards changing the ESP sensor. Unless someone can point me in the right direction ?