Thread: Help with rotting flue pipe

Hello just signed up today to view some photos on another post regarding flue pipes and figured I might as well post this up. Over the summer my original flue pipe that if I had to imagine was 12 years old (age of boiler) gave way and I had a replacement installed. The replacement lasted 2 months and already had some holes in it. I was having a chimney liner installed and the replacement flue was replaced on 9/24/12 along with a new liner put in. Now not even a month later it looks like this:

I would have to imagine that the condensation is leaking backwards out of the flue and running down the outside and burning up the flue pipe. It's only burnt up like that from the elbow down everything in front looks ok on the outside. It's a burnham v7 oil boiler with tankless hot water. We have hard water and I run a salt based softener Heat hasn't been on since April? of 2012. Any Ideas would be greatly appreciated!!

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Hello, Frank. Does the right hand vent pipe we can't see in the picture go into an elbow?
What is the distance from the boiler to the masonry chimney, with how many elbows?
What is the pipe diameter? Is the masonry chimney lined with a small diameter metal liner?
If not, it should be.

The exhaust from your water boiler is not heating the chimney sufficiently to burn off condensation. IMO (in my opinion).

Assume you mean tankless coil for Domestic Hot Water. An Indirect would be better.

Tape doesn't belong on a chimney connector for the oil fired boiler, screws.

Chimney connector isn't rising vertical to a proper offset, duct elbow ng.

Unsupported.

Doesn't look like SW or L-Vent or special SS.

Where is the Baro Damper?

What does the top of the chiimney look like? What did the inside of the chimney look like? I'm guessing tile flue breakdown and lots of water freeze/thaw damage, no repairs, no cleaning, and lots of water intrusion.

What does the breeching look like?

Did you get chimney inspected and cleaned by a pro and the liner installed by a pro? (and the liner sized properly)? or DIY it after sticker shock?

Get the boiler checked out, esp. for damage, and tuned, comubustion analysis? Rating? who determined the SIZING for the chimney connector and re-liner?

Find your manual, and get your specs off the boiler plate, and check the last service ticket.

Get a proper tech in there not some handy-type.

Anyone who slaps aluminum tape on a chimney connector should be run out of town on a rail, or worse, IMO. who did this hack work! (You? )

Who knows what's going on inside the chimney, or that boiler!

Here's some more pics, thank you for the quick replys. The Chimney liner and flue pipe were installed by a local Chimney company. There was tile deteroration at the bottom of the chimney when everything was taken apart. Not many but a few broken tiles were collected at the bottom. The liner is a double wall stainless 6inch diameter which was determined by the chimney people as suitable for my setup. There is a rain cap on top of the chimney as there was before the liner was installed. We will be switching to gas in the spring so I don't need this boiler to last more than the next 6 months or so. The Chimney guy is coming tomorrow to replace the flue pipe and I'm setting up a visit from a local plumber to come and tune up the system. There are screws under the tape not sure why the tape was used as well if it's not really needed. Anything I should ask/tell the chimney guy tomorrow when he comes? Thanks again for the help!

Originally Posted by John Kogel

The exhaust from your water boiler is not heating the chimney sufficiently to burn off condensation. IMO (in my opinion).

AKA The Vent is Oversize and the exhaust is cooling off and releasing it's water and acids.

Vertical rise and first elbow look fine. I'm surprised that that age boiler doesn't have a factory wired auto damper on it. Two things worry me though.
- The chimney liner isn't sticking out of the chimney and visible. If a liner was installed the connection from liner to flue should be visible so everyone knows a liner is actually there. The flue sticking into the masonry makes me worry whether a liner was actually installed or properly installed. It's especially worrisome since that 'chimney wall' looks like concrete.
- You mention the house has a tankless water heater. WHY, who cares, should be irrelevant. Unless someone is making a non-90+AFUE tankless unit it should have no relevance on this. Where is that PVC or SS flue running? If it's running into the flue liner for the boiler, there's your problem.

Originally Posted by Markus Keller

Vertical rise and first elbow look fine. I'm surprised that that age boiler doesn't have a factory wired auto damper on it. Two things worry me though.
- The chimney liner isn't sticking out of the chimney and visible. If a liner was installed the connection from liner to flue should be visible so everyone knows a liner is actually there. The flue sticking into the masonry makes me worry whether a liner was actually installed or properly installed. It's especially worrisome since that 'chimney wall' looks like concrete.
- You mention the house has a tankless water heater. WHY, who cares, should be irrelevant. Unless someone is making a non-90+AFUE tankless unit it should have no relevance on this. Where is that PVC or SS flue running? If it's running into the flue liner for the boiler, there's your problem.

Markus,

Its a tankless coil from the boiler, meaning the boiler runs year-round to provide instant hot water for domestic system. Full fire up for every draw of domestic hot water, and sudden shut down. Should be indirect WH, zoned.

With the history provided and the lack of proper svc., likely boiler is or near shot, corroded.

Off the boiler its not vertical it looks to be about 7-8 degrees tilt opposite (away) direction to the "elbow" (compare to the pipes), it should be a proper offset, which would mean the "elbow" is more severe than an offset or "elbow" in the directional airflow. There should be more of a a rise on the horizontal section of the chimney connector as well, this is not a manifold.

No proving or testing of the baro.

Using B-vent for oil fired is a no-no. You need single wall chimney connector OR L-vent.

That's a barometric damper just ourside the section mortared directly into the chimey.

PS, also noticed the black iron pipe intermixed with copper off the relief valve (backside photo), which doesn't belong there either. I find it beyond hard to belive a licensed professional has tended this oil-fired boiler in quite some time.

Thanks guys yes H. G. Watson Sr. you're exactly right the boiler fires all year round for hot water which I've never liked since we bought the house in 2010. There's definitely a liner in there I watched them stuff it down the chimney and hook everything up in the wall downstairs. I'm going to have him replace the flue pipe today do you think if I turn the heat on now it night prolong some of my leaking issue until I can get a pro out here to tune the boiler? Thanks again everyone for all the advice

I would hazard to guess that the pipe and elbow are improper guage for this application. Probably 30 guage.

Careful examination of the last series of pictures posted, especially the final picture, suggest contact of disimilar metals to the connector. Last series early note copper appears to be contacting chimney connector from the view of the boiler taken at the open solid door...

Most especially, the final photo of the most recent post. The replacement shut/off-isolation valve from the tankless coil has been installed with the stem and handle oriented wrong and to the connector; and the mixing temperature valve "bell" (brass) making contact or near contact with the chimney connector.

In such a case, and especially with the addition of humidity/condensation ambient to the space plus high temps - the first to sacrifice would be the zinc (galv) next the steel. Hence the tremendous rust ('cancer') evidenced there. Leakage, spillage, bypass of high temp-high moisture content - further preventing proper draft.

Suspect additional damage at the baro never properly adjusted or proven.


"boiler room" appears further built-out, enclosed, storage - i.e. less cubic feet of free "air space" and despite closet door louvered - enclosing door to the limited space is solid (but open at the time of picture taking).

Agree with David Bell that the chimney connector is suspect improper materials as well. I disagree with others who suggest the size would necessarily be too large (in fact could be quite the opposite). We have no information on the rating of the boiler's burner configuration.

Originally Posted by Fred Savage

Thanks guys yes H. G. Watson Sr. you're exactly right the boiler fires all year round for hot water which I've never liked since we bought the house in 2010. There's definitely a liner in there I watched them stuff it down the chimney and hook everything up in the wall downstairs. I'm going to have him replace the flue pipe today do you think if I turn the heat on now it night prolong some of my leaking issue until I can get a pro out here to tune the boiler? Thanks again everyone for all the advice

NO. IMO it should be shut DOWN and tagged out until inspected, proven, repaired, and tested, adjusted, etc. by a pro.

I'll throw one more possible cause out there. A small crack in the casting releasing water into the combustion area.

Has any one checked the draft or draft pressure? The damper looks rusty and maybe it doesn't operate properly. Light a match and blow it out or use some other smoke source to see if it's sucked into the damper area. Have a tech drill a hole in the flue above the boiler and using a manometer do a draft pressure check once it's at steady state.

You should be able to find a good boiler guy in the NJ area. Both of my top suggestions have been made. The boiler exchanger may have expanded and excessive moisture is getting sent up the flue or the flue is too large for the flue gasses to properly flow through it.

But, I have that bad feeling that poor maintenance is your culprit and the boiler may have a major problem.

So, back to my first sentence. Call around, maybe, check with some local home inspectors and find a top boiler tech to look it over. Average boiler guys are a dime a dozen; top tier ones are rare. All of us are just making best guesses based on photos, albeit good photos. You need some guy on his knees looking inside that thing.

Good luck.

If you are in Northern NJ, call Ryan & Sons @ 973-398-3978.
He's the best chimney around.

The liner must extend into the room. If that is galvanized steel mortared into the wall, it must come out. Only stainless in the wall now. If it is the snout of a listed tee then that's ok. No foil tape on pipe. Need combustion analysis to see what's going on and inspect liner. If it is blocked or breeched, could explain condensation.

Bill Ryan is one of the best but he's waay up in NORTH Jersey so not sure where you are Fred.

Need to consider long wet times between firing cycles and why if so. Also, what is the Rh% in the CAZ? Oversized boiler can do this, too. What kind of stat? Ditto on the cracked casting, esp. on Burnham V series with thermal shock if no bypass or primary/secondary piping and where does cold water feed in? Is the PV venting causing water to feed often? Check TX tank.

Does this boiler have high draft or is that barometric damper stuck open?

Can you post picture of latest service tag. Also whats the temp sen on aquastat (post close pic if you can). Few things that come to my mind; draft, under fired boiler (wrong nozzle, fuel pressure), hi limit setting on aquastat set for lower temp (should be 180)

I believe it likely that the short cycles for the domestic hot water during the non-heating season could be responsible for the corrosive flue moisture. The boiler doesn't run long enough to adequately heat the chimney to eliminate the moisture.

This is a good un!
If this is in an unheated basement, and short heating cycles - I can see moisture condensing inside the pipe. Appears the moisture is being blown out of the pipe at the elbow joints, as if pressurized there by a reduction of pipe size or squirrel nest further up the vent. A chimney cap is a necessity. Not so much here in GA lately.
We don't have acid rain either- yet. Never seen this much corrosive damage.
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