Stained/Wet Chimney = Boiler Crack?

Jon H

I have a 150 MBH cast iron steam boiler (Crown) that is approx 9 years old. This past winter I noticed that the exterior chimney regularly appears to be wet, and then water stains (like leather shoes that have gotten wet and then dried) appeared.

I flooded the boiler to check for leaks - nothing visible from the outside. I manually feed in softened make-up - typically every other day during colder weather. LWCO is working fine too.

I suspect a leaking gasket between CI sections, but am looking for any suggestions on possible cause, and more importantly, a cost-effective fix. Any proven ways to remove the water stains on bricks? Thanks in advance for any feedback.

Boonierat

...........................................two issues going on

Mr. Hettinger:
Sounds like there are two seperate issues happeing here.

1. The wet stains at the chimney. Are you confident that you're not looking at rain water stains leaking from the chimney flashing ??? (best to eliminate the obvious first)

2. Adding water every other day to ANY boiler means that it's going somewhere. Are there any returns running under the floor ??? If you can't see a piece of pipe, assume it's leaking. Keep in mind; every time you add fresh water to your boiler you're also adding more oxygen. Boils down to 5th grade science class; water/oxygen/iron = rust (corrossion).

Try to keep these two issues seperate, I'd be hard pressed to beleive they're related.

Good luck,
Nels

Jon H

... Not so obvious ...

Nels - thanks for your thoughts.

1. the wet stains are away (opposite side of chimney) from the flashing. The wet spots appeared at the lower parts of the chimney where the boiler flue enters, leading me to think it is steam condensing.

2. I have floor-level returns without buried lines. I have not seen any wet spots along the lines which are all visible. I have replaced most air vents over several years too.

Ed Wallace_2

stains on chimney

i have seen this before caused by a build up of soot in the chimey base have the smoke pipe removed check for a build up of soot foriegn matter in chimney base sounds like you have a steam boiler how much water are you loosing per day? any white smoke exiting the chimney?

Jon H

I have not seen white smoke (steam) from chimney, but the mortar between bricks at base of chimney appear to be wet and white water stains are higher up the chimney. I typically add 2-3 inches (as seen in gauge glass) every 2-3 days. The previous boiler was oil-fired boiler, but I had the chimney cleaned 2 years ago. I will pull out the connector and check for accumulations - thanks for the suggestion.

Ed Wallace_2

stains on chimney

could also be the combustion products eating at the morter inside of chimney gas burns at a lower temperture causeing condesation inside of chimney

Dale

Oil or gas?

Maybe I missed this but the fuel is a key part of this discussion. If it's gas what is the flue temp, too low and you will condense, is the chimney on the outside of the house, is it lined? Unlined outside chimneys on clean heat exchanger boilers will most certainly make some water when the weather is cold. The adding water sounds a bit suspicious, seems too much, get it hot, flood and remove the top cover to look at all sections.

Jon H

true; however, my concern is that this is the first time this has happen in 8 years of owning the home. That is why I suspect a boiler-related problem.

BillW@honeywell

Another angle

Have it checked out by a professional chimney sweep. Insist on a Certified Chimney Sweep, they carry a picture ID with a number on it...this make sure you will get what you pay for. If you can't find one in your area, visit chimcheree@worldnet.att.net to get a referral. Chimney problems can cause carbon monoxide to back up into your home. Get this checked asap, as well as having a pro check out your boiler.

Jon H

Thanks for the suggestion - I have CO monitors in the basement and 2nd floor BRs, so that's not a worry.

tim from Reed Wright

chimney stains

I would lean towards the condensation in chimney. Even though it's been 9 years. Combustion setup could have changed, also it takes a while to saturate the brick. ?? is it an outside or interior chimney. I would be very inclined to install a liner down chimney. Also for your peace of mind, valve off outlet and return and hydrotest and see if you lose pressure.