Chimney flue failing

gmcinnes

I'm writing for my in-laws who are in a terraced brownstone building. IE, their chimney is fully enclosed in the shared walls of the building.

It has 3 flues, 2 abandoned and 1 used for a steam boiler.

When it was inspected recently it was noted that the terracotta lining had failed.

As I understand it there are three ways to repair it: 1) Slip line it, 2) Introduce a metal chimney liner, 3) tear apart the walls of the house and repair the flue brick by brick

Are there any other tricks?

EdTheHeaterMan

An experienced chimney professional is the best choice when it comes to old chimneys like yours.
The other possibility is to use a power vent thru the side wall. Since you are in a townhouse and have shared walls, the only option might be the front or back of your home. That may not be aesthetically acceptable to your home. Just another choice to consider.

gmcinnes

Thanks Ed!

I won't be doing any work myself here. It's just nice to get a diversity of opinion in case there's something the guy they spoke to missed.

I did suggest a power vent to them, but the flue piping would run through their living room and they didn't seem enthused.

Tagging in @Bob Harper

Bob Harper

Get a qualified chimney contractor to perform a level II inspection including video scanning. If they can determine that a properly sized liner can be installed, then there's your answer. If flue tiles need to be removed for a properly sized liner, most chimney contractors can provide this nasty, dangerous work. Regardless, repairing chimneys on a party wall carries the inherent risk of damage to the neighbor. It can break through, dust out both houses, or get stuck requiring walls to be opened then repaired. Slip forming or cast in place requires a straight vertical flue. The tiles must be removed. It can blow out resulting in a room full of refractory cement. They can, in some cases, structurally repair an otherwise weakened chimney. They are best suited for flues that are fired and don't cycle off.

gmcinnes

Thanks for your time Bob.

They did have at least one credentialed chimney contractor look at it. I think more than one, but I'm not sure.

If you happen to know anyone in Brooklyn NY who might take a look at it I'd pass on a recommendation to my in-laws.

Alas, the chimney flue is not perfectly straight. There is a bend inside near the bottom. Not sure of the details, but apparently the recommendation from the contractor is that the 8" liner needed to mate with the boiler cannot be fitted around the bend in the flue, therefore they're going to have to open the walls and repair. Obviously this is not optimal, and made worse because the walls are lath and plaster.

Anyhow, leaving no turn unstoned, I'm working to see if their boiler is, like so many, oversized. If we can fit a smaller boiler we may be able to get a smaller flue size and be able to fit a metal liner. Fingers crossed.

Thanks again!

random12345

I am happy to help with calculating the EDR of their radiators if need be. I consider it a hobby. Let me know. If you do need an extra set of eyes, you will need to take a 1 picture front, and 1 picture side of each radiator, measure the height and thickness of each section as shown below. Look for manufacturer name in the circled areas. If it's a convector measure length, depth, and enclosure height.

gmcinnes

Oh, thanks for that @random12345. Very kind.

I taught my father-in-law how to do it. And I'll check his work next time I'm there. It doesn't have to be perfect, just enough to be able to talk to a contractor with a bit of knowledge and determine if they are space cadets or not.

One guy spent an afternoon in there measuring the square footage of the place and didn't measure a single radiator.

random12345

I edited my comment so you might not have seen the pictures. No worries. Good luck. I enjoy looking through the old trade catalogs.

gmcinnes

Gents:

Sorry for taking up more of your time because it turns out I had a very informative discussion about this in 2019. https://forum.heatinghelp.com/discussion/170552/incredible-shrinking-chimney

I guess the in-laws maybe dropped the ball on this because they didn't want people in the house during Covid, and I forgot I'd even talked about this before.

Gotta shrug. In-laws are in-laws. Can't argue with em. Anyway, they're getting back to it now so I"m getting questions again.

gmcinnes

Very cool @random12345 . I did use one of the simplified charts with height * thickness * a factor for number of columns or tubes.

Since you mention manufacturers though, I know I've seen incredibly detailed charts at one point with factors for each manufacture. It's so fun to go down the rabbit hole with these things.

There's so much paint on these old beauties I don't think I'd ever identify a manufacturer. I'm sure you'd know though

Did you see Dan's 'story' this week? He mentioned something fun about how EDRs were calculated in the past.

random12345

If you get a close-up, well-focused picture of any embossed writing or symbols, even if it's covered up with a thick coat of paint and not legible, there's a chance I can still find out. Knowing the names of the major manufacturers massively reduces the possibilities or "search space" as computer science guys call it.

I did see his story this week. Interesting stuff. The part about the condensate I did not know. Here's another one:

https://heatinghelp.com/dead-men-tales/how-they-rated-radiators/

MikeAmann

Look at these videos:
https://youtu.be/FrleuA_TTrI
https://youtu.be/csvkyP3pP2o

gmcinnes

Oh, cool! Worth asking the contractor about.

I won't be doing any work myself on this. Too complicated and risky of a job, what with old brick, multiple flues, party wall, and most importantly, mother-in-law

Bob Harper

Clay flue tile removal is the most dangerous job in chimney repairs outside of falls. You not only have to worry about getting hit by shrapnel but your hand can get wrapped up around the rods. Several guys have crushed their hands this way. No gloves. You'll need to set up a dust tent with a HEPA soot collection vacuum. You'll need many buckets to haul away the debris. You will need specialized equipment and know how to use it. That includes special poles, 40 lbs wedges, etc. to clear jams. Tile breaking can blow out into a room or neighbor and dust out their house. If the chimney is unstable, it could collapse. It can blow into adjoining flues. If there are no wythe walls separating the flues, plan on relining all flues.

The nunchuk type show works best for medium to large flues. For 8x8's you may be able to get it to work if you shorten the chains.

gmcinnes

@Bob Harper I just had a question from my father-in-law about this chimney. The boiler has an 8" flue, and there is only space for a 7" liner in the chimney.

He's installing the 7" liner, but wondering if, rather than replacing the boiler with one with a 7" flue he can have a top mounted chimney fan installed (with appropriate interlocks etc).


He's wondering if, rather than exchanging the boiler for one with a 7" flue to match the 7" liner he's, he can have a top mounted chimney fan installed (with appropriate interlocks etc.)

I looked at 2428.2 Application of Single Appliance Vent Tables 2428.2(1) and 2428.2(2) as you suggested in another thread, and as far as I understand it a fan should provide plenty of draft for the 7" liner. (Boiler Input MBU = 299; Fan capacity = 337 MBU).

But I know very little. Are there any problems here?

P.S. If you're wondering why I'm asking this here, instead of asking a reputable chimney guy, it's because I don't know how to find one. If anyone knows someone in the NYC that they trust, I'd love to hear. I know you can't advertise as such on this site, and that's something I appreciate, but if you know someone please DM me and you can either give me their name, or I'll give you my number and you can text me.

pedmec

I think you need to find how old the boiler is before you invest all this money just for the sake of a chimney. Trying to get the chimney repaired is not going to be cheap and if your boiler is old you might want to consider how you want to spend that money. I would consider all options.

gmcinnes

Either way the chimney needs to be lined and repaired, so that's decided.

The only question left is whether to replace the boiler with a smaller one that has a flue that fits the new liner, or reduce the size of the flue needed for the current boiler by installing a draft inducer (if that's possible).

The boiler is only 4 years old.

pedmec

Or save your money from installing a liner and install mod/cons. Where there is a will there is a way.

Bob Harper

The sizing tables in the code are for CAT I appliances under natural draft. A terminal exhaust fan makes it a power vented- not draft induced ("fan") in the tables. You would simply contact the fan mfr. and a local rep. would assist with the sizing calculations and controls. The last one I did for a college was a combined input of 1.6 million BTU/hr vented up a 12" round ss liner with an 18"x18" fan interlocked and a sophisticated control. There were complex calculations printed out with all sorts of algorithms for prepurge, postpurge and modulating operation. The fan and controls cost about 3x the liner. It included controls to a standing pilot DHW heater.
I would definitely run the numbers to compare a mod con vs. the Suck-O-Matic option to ss liner.