Steaming Chimney or Not?

JUGHNE

Looks bad huh?

I thought so and went down and flooded both boilers up to the headers.

They are 2001 Burnham Independence units. (Perhaps blessed when they were installed)

They sat quite awhile and no water on the floor.

I think the steam was the heat drying out the chimney condensate.

If you look at the brick, the center 1/3 is discolored from being wet. The face brick is spalling and chipping off.

Liquid has been running out of the basement clean out door.

This originally had a large oil burner boiler, these NG Burnham's got under sized for the job. (By others)
2689 connected EDR to 1266 EDR total of the 2 boilers.

It barely heats the church. 1/4 PSI is the most I have seen on the 5 PSI gauge.

So the oversized flue with 3 cold sides is suffering.

Jamie Hall

Actually, if it was a humid day, that doesn't look that bad to me. The visible moisture dissipates pretty fast. I'd agree the poor thing is trying to dry out the flue...

jesmed1

Are you saying there's no chimney liner? Which state are you in? I thought liners were required for natural gas conversions. Here in MA they definitely are.

JUGHNE

Don't know about a clay liner. Built in 1950.....Nebraska....no requirements for anything at the time.
And even today no agency would inspect the chimney for conversions.

I was there today and just a little steaming as it was about 30 degrees.

jesmed1

Thanks. We just looked into converting from oil to gas here in MA, with an existing terra cotta liner. We would have been required to install a new metal liner, which made the conversion less attractive.

JUGHNE

I did new NG boilers in the local school. It has a huge 1919 chimney for the original coal burner.
No terra cotta liner, just bricks. Old coal converted to NG had a 20" round flue.

Put a 10" SS flex liner down about 45'. Was lucky to get our local utility people with 2 bucket trucks and 4 workers for an hour that was the best $600 or so money well spent. Everyone here supports improvements at the school......these are small town bennies.

jesmed1

Nice. In our big town, they decided the massive "old" brick high school couldn't be remodeled, so they spent multillions levelling a perfectly good building to build a new even bigger one. Big waste, IMO. Sometimes a smaller budget leads to a better outcome.

EBEBRATT-Ed

That's because they can't get grants, rebates etc to rehab an old building but they get all kinds of money to tear one down and build new.

Bob Harper

Chimneys must be suitable for the class of service. All chimneys must be lined and sized to the application. Terra cotta is a failed liner system and should be condemned then relined. This is a cold exterior chimney. If it is condensing this bad, the draft is probably suffering. Regardless, it needs a proper liner. All chimneys should show a gap then a steam plume. Aside from the cap disrupting the free flow of flue gases, this fog at the top is consistent with a weak draft. Once you have the proper liner, perform combustion analysis and adjust as needed. I'll bet the boilers are under fired.

JUGHNE

Thanks for all comments.

I wonder if it is too late to simply install a SS flex liner and hope the masonry deterioration does not advance once dried out.

The draft is weak. Twice the blocked vent safety tripped in one season.

The prints are available and may scope out the construction of chimney.

By "show a gap and then steam plume" you mean clear exhaust for a foot or so and then those fumes condensing to steam above the gap?

Jamie Hall

"The fact that I struggle to find good info about a very very specific question (how/do dynamic orifice traps work in low pressure steam vacuum systems as opposed to non-vacuum systems?) just so happens to also slot in nicely here!"

That's exactly what @Bob Harper means. That would tell you that the exhaust is staying warm enough all the way up the chimney to avoid condensing, which is what you would really like to have.

Got a good chimney sweep handy? He or she should be able to tell you pretty fast if a liner could be slipped in.