DIY: Cleaning Buderus Boiler and Replacing Automatic Pilot

Jim R.

I've neglected cleaning my Buderus boiler (G124X, conventional). The first few times I had a tech out they said it was very clean and these boilers tend not to accumulate dirt like others.

Fast forward about 6 years. There was a $75 cleaning special from a reputable company so I got it done. Once again, the guy was impressed with how clean it was and said he didn't even need his boiler brush.

A few months later I started having problems with the boiler not lighting. If I flip the emergency power switch, wait a few secs then reset, it starts just fine for a while. Happens maybe 1-2x month. The DHW zone is calling for heat, pump running, automatic draft vent open. Just no flame. There is no LED indicator on the auto-pilot assembly (Honeywell S8600H) but I can hear it making a slight buzz every few seconds. Tapping it when it's not lighting does not help. Had to do a reset.

Does it sound like the auto-pilot needs to be replaced?

Also, I'd like to DIY clean the boiler going forward. I took at closer look at the burner tubes and saw some dust and a loose chunk of sediment causing a yellow flame. Otherwise they were burning very blue. Now I'm wondering if the thing was ever thoroughly cleaned. If I do the auto-pilot, I'd like to do my own vacuuming of the inside, check the igniter connection, etc.

I plan on turning off power, turn off gas at the boiler valve, disconnect the gas connections (red arrows) and remove the screws (blue arrows). I'm thinking that should allow me to pull the burner assembly out of the boiler. Does this sound right?

Thanks.

EBEBRATT-Ed

You really need a professional. A real professional with combustion test equipment to service this. Let's not become a news story

Jim R.

Interesting. The professional said he couldn't do a combustion test because the exhaust is sealed and they don't drill a hole due to CO2 issues. He gave it a clean bill of health and said the installation was very nice.

Is the concern that cleaning a boiler not a DIY operation or that the firing issue is something more than meets the eye? If I called a tech for this, I don't even think they would do a combustion test.

JUGHNE

Did he say CO2 or CO?
Drilling a hole is pretty common, I believe.
Not having a tester or knowing how to use it is also pretty common, I believe. IMO

JharrisSeattle

Even if a test port is not available on the flue piping, the g124x is atmospheric boiler. At the bare minimum the tech can take a flue gas sample from the draft hood. It is not technically sealed. IMO, it may be time to have a different pro take a look. Your issue may not be the ignition control module at all, it may be the burner circuit relay inside the aquastat or the damper end switch. You really need a pros eyes on it while its in the failed to ignite state.

GW

Is it stainless steel pipe where the guy "didn't" drill? Doesn't matter, any metal piped gas fired buderus needs to be checked over the block if it's a G124, GC124, GC144. Or if it's a GA124 just stick the probe in from outdoors. I myself don't still stainless

In any case, the flue gas should have been checked, there's not a boiler under the sun that can't be checked

A "chunk", sounds like a chunk of carbon (soot).

The story you're getting from the techs doesn't seem completely accurate

Jim R.

No, not a stainless steel vent. There is no cone type draft hood, maybe that's what he was expecting. I think the draft hood is part of the vent damper box on this model.

The next time it happens I'll check if I'm getting 24v at the ignition control module. My meter wasn't handy this morning.

I would like a combustion test done, guess I just have to find someone who can do it. What exactly should I expect to get from that? An efficiency, how much CO in the vent, anything else? Does it need to be done on a cold startup or after running a few mins?

I had a guy from a big company out. Hard to believe they are not trained in something so basic.

GW

There's not a draft hood ? Is there a metal box under the flue pipe connection?

I'd be curious to see the rear of the boiler.

Co under 100 is the standard. Running for 5 minutes is standard. If the tech doesn't know where to stick the probe it's all a waste of effort. Efficiency changes depending on how hot the boiler is. Should be about 84 or 85% when the boiler is at 170 or 180 degrees

HVACNUT

> @GW said:
> There's not a draft hood ? Is there a metal box under the flue pipe connection?
>
> There is a flue collector on the back of the boiler. No reason a combustion analysis can't be done from the smoke pipe. You're right, he needs someone else.

GW

Not sure if we need to start a new thread here, I've always checked combustion over the fire, not diluted flue gas.

Tim McElwain

The diverter (Draft Hood) is attached to the back of the boiler just drill a hole in the back of the diverter and stick the combustion analyzer probe directly into the boiler sections to get a correct analysis.

GW

yes I just get my hand up in there, kinda hold the probe by its tail so to speak, so i don't get my dainty fingers too heated up. I can feel each section with the tip, so i know where to hang out and get some readings. Each passage needs its own readings.