I Think I Have A Problem.

JakeCK

Was doing some yardwork(all 2ft of it) on the side of the house facing my neighbors driveway. The sun just happened to hit it just right while I was looking up and highlighted it. Anyone else see what I see?

mattmia2

If the flues have metal liners it probably is from the masonry cap on top of the chimney leaking

JakeCK

They do not. It is a clay liner all the way down. Had it and the others inspected about 7 years ago and it was in good shape at the time. The other one next to this one is not used but intact. The third flue that ran through the center of the house was decommissioned and actually torn down last year. 

Had the boiler serviced and a combustion test done in January by a trusted steam/hydronic guy who will remain unnamed but is a member of this site. Unless he sees this and wants to chim in. 

The numbers were good at the time.

pedmec

time to have your chimney looked at again.

mattmia2

Then it could be condensing in the chimney because of the way the newer equipment operates or water leaking in the top because the cap isn't sealed. or both

JakeCK

I'm gut is telling me that it's started to condense as I've tightened up the envelope of the house. It probably just isn't getting hot enough to get the exhaust out before the dew point. Simple fix is a thermostatic by-pass. But I really want to redo the whole system and go with a large buffer tank and zone valves. I sketched up plans a few years ago but have kept that project on the back burner.

mattmia2

So i would start with someone like someone @captainco trained to make sure it is venting properly but it is very common for the masonry cap on the chimney to deteriorate and if water is leaking through that it will make the chimney below it split and spawl as that water freezes.

JakeCK

I'll have to call around for chimney sweep. 

In the mean time here are the combustion tests numbers from January.

pedmec

i think in your situation the stack temperature would be the most relevant to determine if you are getting condensation in the chimney but unfortunately they didn't write it down. i'm not gonna comment on the fact they didn't give you a printed copy. maybe they have old combustion analyser.

ChrisJ

pedmec said:

i think in your situation the stack temperature would be the most relevant to determine if you are getting condensation in the chimney but unfortunately they didn't write it down. i'm not gonna comment on the fact they didn't give you a printed copy. maybe they have old combustion analyser.

Or their printer could've been broke.

JakeCK

I think he has an old analyser. He's an old school fellow for sure. Lol And well respected on this site. 

cubbydog

I don’t know the problem on the inside butt the cap is not constructed properly. A good cap will be made of concrete and overlap the brick by a couple inches and it will have a drip slot underneath so no water from the top of the chimney will will run down the face of the bricks. The cap can also be made of stainless with a bend to devert water away from the chimney!
I don’t think this is the answer you were looking for but it answers the question.

gerry gill

Hi- is this Jake in Parma by chance? Looking like you may need a chimney liner. Technically here in Ohio if you were to get a new boiler the powers to be would ask for a liner on a water boiler. Generally they don't ask for it on a steam boiler. (it is a local code interpretation I think). Try calling Century Chimney and see if they can fit a liner down the flue.

Nimrod66

The white stains may not be condensate from combustion. It may be efflorescence caused by that portion of the chimney being warmer than the other side in winter. The brick structure is not waterproof on the outside and will have moisture migrating through it in multiple directions. Salts carried in the moisture may be pushed to the surface by the warming where they become visible. It's a good idea to line an exterior chimney, cover the entire chimney crown with a cap that drips beyond the edges of the chimney the and to seal the bricks themselves. Exterior chimneys are a maintenance and performance problem from day one. It's surprising that building code allows them.

STEVEusaPA

'cumbustion'....twice...nice

JMGotts

I dunno, but if it were me, I’d take a closer look at the whole picture.

Gman956

Is it gas or oil burner? I thought oil burners are not supposed to have chimney caps?

Geosman

Since you've been tightening up the home...perhaps that boiler is now short cycling allowing that exterior masonry to never warm up above the dew point for the combustion gases? I once had an exterior masonry chimney. The mason bricked it up in the winter using some calcium chloride in the mortar mix to keep it from freezing. That chimney always had white efflorescence depending on which way the moisture was moving through the brick. Seems like a liner and perhaps a good coat of brick water sealer may solve several issues.

Jack

We began to look at these types of chimneys pretty hard after ‘92 when minimum efficiency standards for gas were raised to 78%. It is all basic physics, oil or gas doesn’t matter. When a gas expands it cools. Masonry has never seen a btu it wasn’t willing to absorb. Exterior chimney in a cold climate and almost 30’ of it. You are seeing the efflorescence of condensate leaching through the chimney. I remember the worst I ever saw on this as I was driving thru Bedford, NH. One side of a nearly identical chimney was pristine red brick and the other side serving the oil boiler side was totally white. It looked like someone snapped a chalk line down the center of the brick. Brookhaven did a really thorough study on oil chimneys back in about ‘94. It became Appendix E in NFPA 31. As an appendix it is not a part of the code. The industry was afraid to require lining as it required a $$ liner vs AL for gas and were greatly relieved to stuff it into an appendix to get rid of it. I was on 31 then. Gas found that it needed SS too, but that came along with experience. You have a choice to correct this. Line the chimney according to the sizing in E, which heaven forbid will require reducing the size of the flue from the breech size or abandon the flue going side wall. Be aware that on an exterior chimney like yours it will require an insulated liner. I solved a couple lining problems using 4” pellet vent which was a 2” reduction from the 6” breech. That was pretty extreme but it solved the problem and the boiler was happier. That is an example, not a recommendation. Look at E. The condensation from the flue can also be exacerbated by an excessive firing rate. Short cycling on an exterior flue doesn’t allow the flue to heat up and dry out. The mass of the masonry chimney wins the battle of physics. Net/net masonry chimneys are excellent architectural devices but totally outdated for use with modern heating devices. Exterior chimneys are the worst. When you look at the cost of lining the flue you find yourself having to look at all options. If it is available gas ends up winning in a lot of cases due to the cost of the oil liner. Do you put the money into saving what is likely the original boiler to the house that is 25-30 yrs old or do you step back and do a complete analysis of your options before dropping the dough into the flue?

Charlie from wmass

Your carbon dioxide reading and your stack temperature are the relevant information that you need from your combustion test. Exterior chimneys are notorious for condensing issues and many in the industry with myself being one of them feel they should be remove this option for any new construction through the code. Installing a stainless steel liner and having the chimney flue cavity filled with insulation will allow you to run much lower stack temperatures without as much of an issue with condensing of the combustion products.

Charlie from wmass

Assuming that you have a fairly modern boiler that draft reading is a tad high.

Preiss

You mentioned you tightened your house envelope. I would check for combustion air issues. I also would have a retest done with a stack temp as well. This may not be a new issue it is just showing itself now. If the flu is oversized a ss liner might be the best way to go to prevent migrating moisture. Either way  your flu is likely not getting hot enough and with the envelope improvements you may be short cycling as was said earlier. Again stack temperature is probably not where it should be and it wouldn’t surprise me if the draft has changed since the improvements as well.

JakeCK

To answer some questions. This is not the original boiler to the house, it originally had a coal fired boiler. This is probably the third considering this house was built in 1928, had part of the basement finished into an office including the old coal bin with the coal shoot being bricked in back in the 50s or 60s, and the current boiler was installed sometime in the 80's. 

It is a Weil McLain gas boiler, cgm series 9 if I'm not mistaken. 140k btu input, 120k btu output. At least 2x oversized. But I have no intention of replacing it. A large buffer tank would resolve the oversized issue, and a by pass would resolve to low of return water temps. The boiler it's self is in excellent condition. This is a converted gravity system so it takes a lot to heat it up and my radiators are most certainly oversized. It doesn't short cycle, run times range between 10 to 30 minutes. But due to the mass of the whole system it simply never gets that hot except for the rare times I do a set back. The scary thing is I haven't insulated the house yet, And new storms should be getting installed in the coming weeks.

And before someone mentions it, I'll go with an a2w heat pump before I would consider a mod con. 

I'm curious what @captainco thinks of the suggestions of a liner?

JakeCK

gerry gill said:

Hi- is this Jake in Parma by chance? Looking like you may need a chimney liner. Technically here in Ohio if you were to get a new boiler the powers to be would ask for a liner on a water boiler. Generally they don't ask for it on a steam boiler. (it is a local code interpretation I think). Try calling Century Chimney and see if they can fit a liner down the flue.

Yes this is.

I'll look them up, thank you.

JakeCK

Jack said:

 Do you put the money into saving what is likely the original boiler to the house that is 25-30 yrs old or do you step back and do a complete analysis of your options before dropping the dough into the flue?

I wish my house was only '25-30 yrs old'. Lol You're off by at least 64 years. Knob and tube wiring, no insulation, wood weight and pulley double hungs... Leaks like a sieve even after tackling the air leaks between the basement and attic.

Preiss

You likely have a very large flu that worked well with hot exhaust gases that coal would have produced. Natural gas is a much cooler beast and it is likely even at a -.03 draft (if that is actually what it is at currently), that it is likely an indicator the temperatures are not hot enough and the dewpoint is being reached before the flu gasses can escape. A smaller ss reline would hopefully heat things up and create more draft, at least -.04. This would likely affect your efficiency but your moisture issue may go up in smoke.

pedmec

you need to have a boiler bypass or similar set up installed at your boiler. your cool return water system temperature will show up as a cooler stack temperature. system bypass, primary/secondary piping, fixed mixing valve will all serve the same function, raise the boiler temperature above the dew point of the flue gas. and have the o2 tweeked down a little, should be in the 5-6 range, provided it does not create CO or increase current CO situation.

captainco

White stains are from flue gas condensate. If it was from water everyone would have white chimneys.
Something I mention in class is the thermal conductivity of different materials. This is there ability to absorb and dissipate heat. Clay or tile is the lowest on the list or in other words, absorbs and cools down flue gases less than any material. Stainless steel is a lot better than aluminize steel but not better than clay. Aluminum is the worst venting material as far as keeping flue gases hot.

Condensation is caused by low flue temperatures(underfired) or low draft. The draft reading is adequate which indicates plenty of combustion air. However, higher draft can draw in more dilution air if this is a drafthood boiler and cause the flue gases to be much cooler and condensate.

Unless the chimney is falling apart, I have never seen a job where putting in a flue liner fixed the problem, but it sure helps hiding it. I know, heresy, blasphemy. 42 years of combustion testing says otherwise!!

captainco

Just one extra recommendation. I don't care what you use for draft testing everyone needs to get a Dwyer 460 Air Meter. This is the most functional and visible tool you can own to diagnose venting and combustion air problems.

Ken Johnson

Re the windows -- I have an old house with counter-weighted double-hung windows. Installation of spring bronze weatherstrip made a big difference. Not trivial, but labor and materials less than for window replacement. YMMV, of course. If you go that route, make sure you have replaced any existing counterweight ropes with chains first. The ropes will fail eventually. If it was an upper sash it won't want to stay up, and there is a fair chance the fallen weight will interfere with the movement of the weight of the lower sash.

BennyV

It's not short cycling, so there's no real need for a buffer unless you want to outdoor reset the heating loop for comfort. You probably do have low return temps for a while though with such a high mass system, so you need some sort of boiler protection. The system would be much more efficient with a modcon, but since you want to wait for a better a2w HP and not commit to another gas burner, dealing with the boiler protection would be the best bet. With a well insulated house and a much lower load, you'll need even lower water temps, making the old boiler just as inefficient as ever, but that much better for a future a2w system.

JakeCK

I went with a company that @captainco recommended. Tomorrow he's going to be picking up the signed contract and deposit check.

Work is going to include a double acting barometric damper, addition of safeties, and adjusting the boiler. Work should be completed with in the next two weeks. Just in time for heating season. 

captainco

You will be pleased!!

JakeCK

captainco said:

You will be pleased!!

I'll be sure to post pictures when it's done. 

I had also gotten a quote from him to replace the near boiler plumbing because it is honestly a cluster. But I couldn't justify the costs on that since I'm still not sure what I'm going to do long term. Once the dust settles with that recent act that just passed I will possibly move to an a2w heat pump. But I do not know if I'll keep the NG boiler as backup or go all in on electric and get an electric boiler for backup. In either case the overriding consideration for correcting the venting problems with the boiler as is, even if I do not see a positive ROI, was safety and stopping any further deterioration of the flue and chimney. It is possible I will not act on any other changes for a year or two in order to maximize tax benefits. 

hot_rod

Heat pumps have been outselling boilers in Germany for a number of years now. And one if the worlds premier boiler brands just brought this to the US market?
The times they are a changing  

JakeCK

The boiler is not tuned yet, and the barometric isn't adjusted. He also has to add the rollout switch. Didn't have that one on the truck. All of this will be done tomorrow because... We actually discovered a new problem. Luckily this one won't cost me money. The regulator on my gas meter went bad. It is clicking outside loudly and the gas flow to the boiler was fluctuating really bad. It would roar good for a second and then drop out, and then roar again before cutting out in sync with the gas meter.

My guess it went bad from basically sitting for the past 5 months. Seriously I have only used 9 ccf since the beginning of June. 

Gas co is coming out tonight. 

random12345

hot_rod said:

Heat pumps have been outselling boilers in Germany for a number of years now. And one if the worlds premier boiler brands just brought this to the US market?
The times they are a changing  

That's the worst of all worlds right there. Higher costs and higher CO2 emissions. Lose-Lose. Germany is a terrible example to follow.

captainco

That looks really good. I knew they would do a great job!

JakeCK

Gas Co just finished up. They had to replace the whole meter. I have the boiler lit now. Letting it do a nice good burn to put some heat in the house before shutting it down for the night. Since the barometric and boiler isn't tuned yet I'm not going to just let it run. 
The HVAC tech will be back out tomorrow to finish up. He couldn't get anything else done today with the meter acting up.

That said it is running pretty good. I can see the barometric working even though it doesn't have any weight on it yet.

captainco

The barometric comes preset for normal draft needed by equipment. It is rare when installed at that location
that it would need any additional adjustment. But if it does, it will be done.

Charlie from wmass

captainco said:

The barometric comes preset for normal draft needed by equipment. It is rare when installed at that location that it would need any additional adjustment. But if it does, it will be done.

Since when are they factory set?