Severe Chimney Leak

ETLAAA01

Hi all,

Came to this forum looking for advice as to what may be causing leak from my chimney. for some context, I have an old home built in the 1880s with slate roofing. I had the flashing repaired.

I first noticed this leak in my finished attic in february of this year, around where the chimney meets the attic ceiling. This leaking seems to occur only when my boiler is on and has been running. Could this be flue gasses leaking in from a bad liner?

When I had my flashing repaired I was told by the repairmen that he stuck his hand down into my chimney and felt a lot of moisture.

I have a Burnham V8H Oil Boiler for steam radiators, it is vented up through my chimney.

Any advice on this, and how to further proceed would be greatly appreciated. thank you

Jamie Hall

Is the chimney lined? And if so, with what? It is rather unlikely that it is condensation from flue gasses — at least if the lining is in decent shape. However, there would be no harm at all in having a good chimney sweep really inspect the chimney from top to bottom; the better sweeps usually have cameras they can run down and really see what's going on.

There is, however, another possibility: this is a brick chimney? What is the condition of the brick and the mortar and any cap on the brick? Granted that seepage through the brick or the mortar wouldn't correlate particularly with when the boiler runs, but it's worth looking at rather carefully. If the bricks haven't been damaged by overambitious cleaning, that sort of thing can be repaired.

delcrossv

If the boiler is sending steam up the chimney, it could do that. Is your boiler using a lot of water?

ETLAAA01

Its hard for me to say how much water it is using, it has a low water cut off and an automatic water feeder leading into the boiler. is there a way for me to see usage beyond that?

EdTheHeaterMan

You can monitor water usage by shutting off the feed water valve to the automatic feeder. Then as the water level drops below the safe line the burner will stop and you will need to manually turn the water on to get the water level back to the center of the gauge glass.

First you want to check that your Low Water Cut Off (LWCO) will turn the burner off if the water level gets too low. If it does not do that, then you need to get that fixed first.

If you need to add water more than once a day, then you have a substantial steam leak or water leak somewhere. If it is inside the fire box or heat exchanger (HX), letting water or steam into the combustion side of the HX, that could be your problem. If you need to add water once a week, then you do not have a leak that needs to be addressed. If it is between those times, then let us know the specifics.

As far as Chimneys built in the 1880s There is a strong possibility that there is no clay liner inside that chimney. You will need to address that problem with a Chimney Professional. There are some contractors that believe that if the old boiler worked in that "Liner-less" chimney, then the new one should work just fine. NOT TRUE. I have visited several turn of the century homes (the 19th century) where a gas boiler and a water heater vents were dumped into a brick chimney without a liner, and there were nothing but problems. Back drafting and condensation of flue gas that ate away at the mortar leaving the chimney look like swiss cheese, caused the pilot flame to constantly go out.

It never fails, the people that live in those homes are always in their 80s and can't handle the maintenance needed to operate the house they were born in and want to die in.

delcrossv

https://forum.heatinghelp.com/discussion/comment/1815438#Comment_1815438

Aah. The dreaded auto-feeder. Do what @EdTheHeaterMan says and report back .

ethicalpaul

If you need to add water more than once a day

I would say "week", not "day"

delcrossv

https://forum.heatinghelp.com/discussion/comment/1815476#Comment_1815476

Really. My oldest system is an 8000 sqft 4 flat with 32 radiators. If I didn't have to flush the LWCO once a week, I would maybe have to add a little water every month or two.