Buderus burner looks suspicious

aarona

Buderus GB142 giving 6A error code sometimes. This started after I decided to try the Auto mode which I thought would use the outdoor sensor to adjust water temperature automatically. Rather, it seemed to run at 190 the few times I checked in on it while it was on Auto. Highest I ever ran it in the past was 180 and only when -25F outside.

I will be checking the flame sensor. I think the shroud on that is slightly warped now. It was much worse--completely warped and failed--when we bought the (foreclosed) house 3 years ago. Has worked great after I swapped it out back then.

There is also some dark goo in the middle of the burner. I can see it "rippling" in the breeze while the burner is running. Very dark/black. I can't find any discussion of such a phenomenon. Time to replace the burner?

HVACNUT

Suspicious? Ya think? That's supposed to be almost a half circle screen around the HSI. Looks a little curly. Has it ever been serviced? Has it ever been serviced by a pro with the instruments to properly test, check, and diagnose?
How old is it?
What condition is the rest of the boiler and parts?

SuperTech

Those boilers are pretty high maintenance.  Anytime I come across one it's usually neglected and in terrible condition. These particular boilers don't seem to hold up well under ideal conditions, if it's been over 3 years since the last proper service I'll bet it will need quite a few repairs on top of a good cleaning. Condensate trap, flame sensor, igniter, probably a few gaskets. 

aarona

Age of boiler is unknown. I would guess about 10 years. No actual service within past three years although it was given a "look" by a boiler tech doing some pipe work back in 2021.

Overall the unit looks pretty clean, decent piping, etc. We were super happy that the $120 sensor replacement got us a working boiler instead of having to replace it, given that pipes had frozen, cast iron radiators cracked, etc. I suppose now with some years of good operation and it is seemingly not a basket-case unit, some pro maintenance is a better idea than swapping a sensor every few years.

But I am curious what that goo on the burner is?

SuperTech

Those boilers get nasty just from normal operation.  They are usually worse when burning LP. That's why I say they are high maintenance and require yearly cleaning and tuning.

Big Ed_4

Replace the hot surface and flame rod ... Every 5 years for maintenance . A signal is sent though the igniter ..

PS Alway take note of the sub code . While in error push the wrench button for sub codes .

aarona

It is natural gas, not LP.

A technician was here and looked at it. First he said he knew exactly what was wrong and polished the flame sensor (emery paper or something), which was pretty crusty. Then he said it looked like there was something on the burner, popped the burner off, and a stream of water sprayed out.

A pinhole leak in one of the top fin sections just happened to be spraying on the burner, so the "dark goo" on the burner was actually water continuously running down the face of it.

Date code shows 212th day of 2006. 18 years is a pretty good run for one of these, from my understanding.

EdTheHeaterMan

You could always try a little bubble gum on the leak. I like Bazooka myself.