1920's american standard converted coal fired. Should I upgrade?

Todd_33

I have a 1920's rental building of 10,000 sq feet of 7 apartments and 2 store fronts in Milwaukee with the original steam boiler that has been chugging along more or less faithfully for 80 years. I've had the building 5 years.



It was originally coal fired, then converted to oil and now gas with a 950,000 btu burner. The flue pipe going the chimney is about a foot across and gets pretty hot when she cranks up. I imagine $$$ flying out. Anybody have any idea what percentage efficiency I am at now and what I can get to with a new boiler, keeping cost to a minimum. I've gotten telephone, ballpark cost estimates of $15K to upgrade not necessarily including asbestos removal. Thanks Todd H.

BobC

LOTS of fuel

going up the chimney! That beast could well be delivering 40-50% efficiency, converted coal boilers last a long time but you pay for it in spades with all the extra fuel your burning.



Replacing an asbestos covered boiler is going to be expensive but if it's done right you will save a lot of money on fuel. Don't just go with the lowest price, you need the right boiler properly installed to make it worth your while.



A wet based boiler with a power gas gun gets up around 85% and if you get a staged gun (high and low fire) you can save even more. Use the find a contractor link at the top of the page to see what pro's are in your state, the longer you wait the more fuel goes up that chimney.



Bob

nicholas bonham-carter

Improving 80-year-old efficiency

Maybe a damper on the stack would reduce standby heat loss. Does the present burner have a 2-stage gas valve which could be activated to start on high, and then switch to low-fire when the pressure gets to 2 ounces?

How is your main (not rad) venting?--NBC

Todd_33

Thanks for quick reply

Not sure how to put in a damper. There actually is one there but it is not in line with the exhaust. It is on a short 90 degree pipe and dampens an opening directly into the room. I figured it was for when the wind blows across the chimney causing a vacuum down the flue.



I've added several Gorton vents in the various legs of boiler. Reduced operating pressure from 8/9 to 2.5 lbs. That's about the lowest the lowest the pressurtroll will go. Worked with both cut in and out. I studied the heck out of THE BOOK after I got the building.

Todd_33

Does a high efficiency steam boiler vent out the side of the building?

Thanks for the input. I was thinking maybe 50%+ efficiency. Might be as low as 40% huh? If the 85%er vents out the side then I could remove the chimney if that gets too decrepit. I wonder how long the project cycle would take to map the current system and plan and install the new boiler system? Guessing this project would take a while, so it's a little late in the season to be looking into it. I like the idea of 2 stage burner. I think that longer burning cycles would be better than what I'm seeing now.

Steamhead

That's a barometric draft regulator

not a flue damper. The latter closes off the flue when the burner is off.



Post some pics of the boiler and burner so we can have a look.



I've been to Milwaukee- do I know this building?

Larry_52

Half joke

If I could I would go back to coal, he'll of a lot cheaper to burn.

Todd_33

Been to Milwaukee?

Sorry 'bout the delay. I don't know if u know this boiler. Maybe before I got it. Plan on coming this way soon? Stop by and take a look - I worked on it today, several pin hole and small stream leaks in wet legs. Got them plugged, maybe. New boiler in spring for sure. Maybe can get energy credits.



This is a combo 1 and 2 pipe. Signs are that the 2 pipe was added after initial install.



Thanks for the input.

Todd_33

Too old and back too sore for coal!!

As I said...



This unit has a 1,000,000 btu single stage burner. I wonder if I could get by with, like 2 500k btu boilers with dual stage burners to keep a slow heat going. Theoretically that should give me 4 stages. I heard about a guy that might have a couple 4 yr old 500k btu that might be available. He bid on a steam to hot water conversion so may get the old boilers. Is that goofy?

Todd_33

Is wet based still steam?

It's a pretty old system. Also partly 1 pipe. I don"t know if the rads would hold water. Unless i misunderstood "wet based".

nicholas bonham-carter

boiler replacement

how do you know you need 1,000,000 btu's? have you calculated the EDR total of the system?

what sort of boiler is this-sectional, or tube type?

there could be some things you could do to improve things for this winter, such as maximizing venting, and keeping the pressure low. you may even be able to down-fire it if it is too big.--NBC

Todd_33

I'm reasonably sure venting is ok. have 5-6 Gorton#2s on various legs.

I reduced the pressure to 2.5 lbs which is lowest I can go with the current pressurtrol. The burner was converted from oil. I don't know if it's adjustable. I don't think I should mess with that.



Thanks for the input.

Steamhead

I won't be there again

until probably late spring. How about some pics?

nicholas bonham-carter

Checking the venting

A low-pressure gauge (0-3 psi) would show you how close to adequate your venting is. I have a 1,050,000 btu system, and I have 18 Gorton 2's.

Maybe it's time for a vaporstat, instead of paying for excess pressure. My 55 rads heat at 2 ounces most of the time with no temperature setbacks.--NBC

BobC

Wet based

A wet based boiler is constructed so the water jacket surrounds the firebox, they are more efficient than a boiler where the fire sits underneath the water vessel (like a tea kettle on a stove).



A wet based boiler can be steam or hot water and some are converting oil fired wet based boilers to gas using a gas gun to reap the savings compared to oil and retain the greater efficiencies offered by wet based boilers.



Be careful with AFUE numbers because they do measure how much heat a device produces from a unit of fuel but it does not care where that produced heat goes. A warm cellar is nice but not very fuel efficient.



Bob

Dave in QCA

Current Burner tuneup?

Do you know what kind of boiler this is? Is it a steel fire tube boiler, cast iron sectional boiler? If it's a sectional boiler, is a 2 pass or 3 pass? Most of the time, but not always, when smaller coal boilers are converted to gas they get an atmospheric burner installed. In most cases, these don't run very efficiently, especially in those old snowman type, vertical stack round sectional types.



However, if its a fire tube type, those usually run very efficient, dependent on the burner tuning of course. Cast iron sectional boilers can also be reasonably efficient, especially if they are a 3 pass type. They need to be kept clean and the burner needs to be tuned properly.



If it were mine, I think I'd do a little analyzing. When the boiler starts, how long does it take for you to build pressure. If it happens pretty fast on a cold system, say 30 minutes, you are probably providing too much steam. So, A radiator survey is the first thing I would do. Measure all of your radiators. You can look at the tables and come up with the total sq ft of each radiator. Then you'll know what the input of the boiler should be.



A few years ago, a good friend of mine replaced a 105 year old firebox / fire-tube type boiler on a large residential hot water system. The new boiler is also a steel fire-tube type, a Burnham 4F type with a Powerflame burner. The new boiler is great, but running cost is no better than the old one.



As you move forward through this process, DO NOT consider conversion to hot water. Many times the results are a disaster and at best, the payback is minimal the investment is great. A well operating steam system is pretty darned efficient.

Yahu

Why upgrade when you can enhance?

Why not use a heat recovery system?



I am currently working on a chemical heat storage system design for my own solar system. Heat pipes in your exhaust could recover much of that energy and redirect it to a storage system chemically storing the energy for later use. 'Heat pipes' are just vacuum sealed pipes with a small amount of fluid like water or acetone that boils rapidly in the vacuum and carries the heat to condense in another location rapidly. They can be easily made from sealed copper tubing.



A Zoelite heat storage system can store 180+ kWh/m^3 and store it without loss until released. I am building a system out of a 55 gal drum and a few hundred dollars in parts and ingredients. Granted, I will have to program my own PLC to manage the system. It will be like a heat battery that can be charged and discharged as needed.



There is a German company that already makes Zoelite heat storage systems to collect waste heat.