Harman PB105 overheat safety zone light

[hoseheaddave]

a few years ago my wife and I had a Harman PB105 pellet boiler installed, we also have our domestic hot water ran into the unit, my current problem is when I tried to fire it up this weekend, the Overheat Safety Zone light came on, and the auger wouldn't feed pellets into the burn pot, so I called the dealer we got it from and long story short , I'm not dealing with them anymore, their customer service after tha sale sucks, anyway when I talked to the dealer they told me it sounded like the aquastat sensor, I also talked to a couple other dealers and a tech rep at Harman and they all said to start with that item, I bought a new one and put it on and the boiler does the same thing as before, there is no error codes flashing on the control panel, but I did notice now that as soon as I turn the pellet feed dial to the test position to see if it will run, the Overheat Safety Zone light comes on, I tried to let the unit run for a while without touching anything and the light remained off, until I turned the feed dial, I tried to watch the control panel when I turned the power on, and the status light flashed once and then stayed on, in my book it says it could be a problem with the control board, I'm trying to fix this myself because we are in a rural area and it's going to cost me $200-$300 just for someone to come look at it

 

[Former Farmer]

Did you try starting the boiler with the aquastat unplugged from the control board? I don't know if it would work, but may be worth a try.

I had to replace my control board last year. The relay for the ignitor was stuck closed and would blow out the fuse on the control board after 15 to 20 minutes. If memory serves me right, the control board was around $200 from my dealer.