windy day affects air intake?

sunlight35

My gas boiler air intake is using the chimney for the previous oil boiler, I just noticed when the wind was blowing hard the boiler failed the ignition the first time, it sputtered like crazy, it almost failed the second time but was able to get the flame going. My question is can strong wind cause the air intake to suffocate?

JUGHNE

The chimney is still a chimney. Creates an upward draft.
The more wind across the top of the chimney, the more draft created. Doing the opposite of what you need.

sunlight35

I see, so it's similar to ridge vent. Anything I can do to alleviate this effect? Would it be advisable to draw some air from inside the house?

Jamie Hall

How is it that the boiler is taking air from the chimney (which is quite possibly the worst place)? Is there a pipe going up the chimney?

Have you access to the boiler install manual? It will probably tell you how the boiler intake -- and exhaust -- should be arranged. Some boilers may take air from in the space -- provided the space is big enough -- and exhaust through a lined chimney. Others may have quite specific requirements for combustion air intake and exhaust routings to outside.

sunlight35

There is a round cover at the bottom of the chimney with a hole in the center, and a pipe is connecting from there to the boiler.

Is there any drawback from taking air inside house besides energy efficiency?

Edit: By the way, sputtering existed before when the air intake pipe was disconnect to draw air from inside of the house, so I am not 100% sure it's due to lack of air.

Jamie Hall

Frankly, I doubt very much from the sound of it that the installation meets any known manufacturer's directions (they are not recommendations, by the way -- they're important) -- or any existing codes.

Where does the exhaust from the boiler go?

Zman

What model boiler?

sunlight35

Vitodens 200-wb2b, exhaust is going out to the side of the house, and the pipe is pitched.

Zman

There are Viessman guys on the site that can comment on piping that model in that way. In general, you don't want the CA and vent to take drastically different paths. Has a combustion analysis been performed?

sunlight35

Not that I know of. Sputtering has happened since the first fault light came on this past February. In the recent months it never went away completely, sometimes ignition was almost silent, sometimes after a couple of bangs. Four or five failed ignitions and the fault light would come on, which hasn't happened in the last one thousand cycles.

JUGHNE

If the air intake pipe was removed from the chimney and the hole left open, the chimney may have put a negative draw on the room possibly giving you the same effect.

You could remove the pipe and use inside air....but plug the chminey hole the pipe came out of.
If still a problem, then open a basement window (one that you can feel air coming into) and see how that works.

Jamie Hall

OK. Couple of points here. First, drawing air down the chimney -- or trying to -- is going to be problematic. Don't. So far as I can determine, that boiler is designed for -- and therefore must be used with -- sidewall venting; either coaxial or side by side. Check the installation manual and local codes.

Second, if the "sputtering" has been going on for some time -- like 9 months now -- have you had the burner properly adjusted by someone with the necessary equipment and know-how? These things aren't plug and play, and the continuing problem with combustion tells me that -- in addition to the existing intake and exhaust setup, which will make it impossible to get anything close to a consistent adjustment -- the burner is probably way out of adjustment.

sunlight35

Yes the boiler has been maintained annually by a Viessmann contractor (ViPRO), and he replaced parts necessary earlier this year, I knew he was on the phone with a Viessmann engineer regarding the sputtering issue and they have checked everything they could think of, including the system board, gas pressure, etc.
Boiler has Lambda Pro which can adjust for optimal combustion itself, does this thing have adjustment that contractors can do?

EdTheHeaterMan

 Tech support Can’t see thru the phone lines.  They assume the air intake is properly installed.  They probably don’t know the air intake is from an old chimney.   It would help for them to know that during your next conversation. 

JUGHNE

IIWM, I would pipe out the same side wall as the exhaust for the air intake.

Install book would show the approved method.
Then have comb test done.

Is this the LP unit you posted about earlier?

sunlight35

Yes, right now it's on one-pipe system, taking air from inside house. I saw some corrosion next to the opening of venturi extension, could likely be flue gas recirculation issue.