The case of the warped burner head, this weeks case.

RayWohlfarth

In this weeks case, I was asked to look at a commercial building and saw an old burner head laying on the boiler room floor. The head was warped and pieces of it were missing. The service contractor told me they had to replace the head every two years. The back story on the building was that half the hydronic loop was capped off because the owner installed a rooftop unit to provide heating and cooling. What do you think caused it? I will let you know Friday morning.

ScottSecor

Here's my guess. Burner head/tube exposed to reflected heat. Burner mounting plate did not have thick enough insulation and or burner head was not wrapped with Kaowool. On the other hand, I have seen something similar from inadequate air for combustion (looooong term).

Steamhead

Boiler now oversized for the load, and can't shed heat fast enough, so firebox overheats and burns off the head.

retiredguy

You never said what fuel they were burning so I will take a stab at it. At one time those burner heads were made of cast iron but that changed due to cost. That looks like a Gorgon Piatt burner but I digress. Usually, the burning of the head is from the wrong oil nozzle, the burner head not being protected by the front refractory, poor flame set-up think primary or secondary air, incorrect burner input, or a crap burner head. Some of those commercial burners had a very poor low fire flame pattern and would overheat the burner head if kept on low fire too long.

mattmia2

I'll go with they downfired it because of the reduced load and didn't change the right parts on the burner/went further down that the boiler was capable of.

Or what @retiredguy said about it running on low fire too much.

JUGHNE

The RTU is putting a negative pressure on the building and pulling the flame back towards the burner?

EBEBRATT-Ed

The only two things that I have seen cause this and they were both mentioned above.

1.Back draft down stack if the boiler room is negative when the burner is off
2. Improper refractory and or insulation around the burner tube

The Steam Whisperer

We've seen another in the Peerless SC boilers.... They are pushing lots of btu's into a very small chamber and there is no post purge on the burners. All three Peerless SC's we installed warped or burnt the burner heads, flame sensors, etc. with 3 different burners. The chambers are probably running so hot that on shut down all that heat cooks the burner head. The mod burner lasted the longest before problems started. One boiler we were able to downfire after we orificed the two pipe steam radiator valves and that one has done alot better. We replaced the other two Peerless SC's on our dime.

SgtMaj

Fuel mixture too lean

propmanage

Without seeing the draft and stack temps could be a lot of things. But I would think if all the chamber components are in tacked could be the wrong nozzle and no draft i'm just not sure why it's so clean. Unless it’s the wrong burner for that boiler. The last time I noticed a retention head glowing. They secured the electrodes on wrong, and it was directing the air flow not allowing full the flow of the flame.

SKYPAINTER

I suspect some kind of water flow issue through the heat exchanger, too low or no flow / dirty combustion chamber but you usually have other issues / poor venting might be something to look at too.

SuperTech

My guess is poor draft or backdrafting causing the chamber to over heat. I only work on residential stuff but when I find cracked flame retention heads those are the common culprits. 

Bill_Kitsch69

Needs insulation protection most likely as Scott Secor suggests here in comments. Not enough info to properly evaluate.

Dave338

Low fire set too low.

nicholas bonham-carter

We had a big rooftop Lennox heating and cooling package unit, which would go off on safety, on cold nights, requiring a trip up a ladder to the roof!, to push the button!
Several Lennox certified companies threw parts at it, to no avail.
Finally one super diagnostician discovered a crack in the burner head, producing a cold spot in the flame, which, when it passed over the flame rod, tripped the safety.—NBC 

RayWohlfarth

Thanks for the thoughtful theories. In this case, the boiler was grossly oversized and stayed at low fire for most of the heating season. My suggestions were two fold. I had them increase the air at at low fire to provide more turbulence to better mis the air and fuel. This also pushed the flame away from the burner head. The second thing I did was to widen the differential. It was set at 5 degrees F and I changed it to 20 degrees. This allowed a longer run time and heated the flue more, increasing the draft. Not sure if these were the solution but it worked in this case. They didnt have to replace the burner head for the next five years when they removed the boiler and installed a packaged rooftop unit. Here is the link to the video

https://youtube.com/watch?v=vmn6d8QINac