Arrived on site to diagnose boiler sooting up again. We provided an estimate to deep clean the heat exchanger. It was accepted so we disassembled the top of the boiler and removed the burners. We brushed the top of boiler and vacuumed it all out. We got as much soot out as we could with brush/vacuum before we rinsed the heat exchanger to get even more out. Once we got it as clean as possible, we dried it out and then reassembled the unit. Test fired the unit at the recommended gas pressure of 9.8”. The boiler refuses to burn cleanly at the recommended pressures. Set pressure back down to 5.15” and performed a combustion analysis. After running for a while the CO in the vent dropped to 2ppm. This is as clean as I can get the boiler to run. There are no other CO leaks or sooting anywhere that I can see. Ran the boiler for 35minutes or so while I was waiting on hold with buderus tech support. They kept telling me what the pressure should be and eventually I got transferred to someone else
