Experience I had with a boiler tech and what I learned along the way.

A couple months ago I noticed my boiler kind of smelled funny in the same way a ventless space heater kinda smells and its been lighting with a big woosh. My cousin works in the office of a heating and cooling place so I decided to have her send out their boiler tech. I specifically told her I wanted a combustion analysis done on it.

He shows up, looks at my old 1955 boiler and asks if I run it alot which struck me as an odd question. Like yea when its cold I run it.

So I leave him to it. He takes apart the thermo couple, then puts it back togeather. I'd assume he checked out the gas valve but I wasn't watching him too closly. Anyway 10 minutes later he is done and lights the pilot. Tells me my cover is home made and I should tape off the vent slots that are in it since that is how the original would have been. He grabs his combustion analizer and Calls for heat so the boiler lights with a big woosh. Sticks the analizer in the opening by the PRV and gets 5ppm CO. Calls his boss ,steps outside to talk to him then is told to shut my boiler down and it needs to be replaced for $10k.

He goes on to tell me its a bad seal and can't be fixed packs up and leaves. Looking back he had to know the roll out would cause CO to go into that area because it has a clear path up to that area just outside the combustion chamber where the roll out is happening.

So I spend a couple days on the internet and ask people on different forums/groups and go about checking the boiler out my self. I bought a bacharach insight plus and did my own combustion test since he never ended up doing one. The CO in the exhaust was pretty high so clearly inefficent air fuel mixture.

I learned online that orange flame is typically just pollutants in the air but yellow like a candle is no good. So I look at the burners and a few of them have yellow so I adjust the air damper till its burning nice and blue. That yielded better CO results but still not great.

Next I removed the exhaust pipe and looked down into the heat exchanger that was clearly fouled up with carbon and other crap from it not burning right. I ordered 3 different brushes and when they came in I setup my bagged vacuum with a hepa filter, put on a respirator and went to town brushing it in every which direction I could till it was all clean. I used a bore scope to check all the seals along the exchanger sections and it was all good. Cleaned the burners out real nice and put them back.

I used the monometer on my analizer to check the gas presure and adjusted it .1. I also got rid of the 5" exhaust pipe and made it 6" exhaust since that is what the opening on the boiler is and I used a chart to figure out what size it should be for the BTUs I'm putting out and it also confirmed 6" was correct. I found that the burners were starving a bit for air so I added the square screen section to the door since it originally only had the slots at the top for air supply and that helped it quite a bit.

So after a day of cleaning and adjusting everything I got it all back togeather and got my CO in the vent pipe to be 0ppm and 0ppm by the prv opening. Here are some pictures.