Steam boiler dry fire, huge fuel savings with new boiler and piping

ttekushan_3

This a reminder that blowing down float controls and actually testing their operation are two different things. A client found this out the hard way. I hadn't been out in a couple of years since the 1970 Bryant was running "fine" although it was a gas pig. A few weeks ago I got a panicked call, "The boiler room is 500 degrees!" A bit of an exaggeration, but its a darn good thing he didn't have paints and solvents near that boiler. The jackets had acquired that attractive ashen white look. He put a glove on to pull the electric shut-off since the handle was too hot to touch!



Though that old bryant and a Dunkirk D248 may appear nearly identical, the D248 is a far more effective and efficient boiler. Several years ago I did a complete water and fire side cleaning of the bryant to get control over the high stack temps and terrible fuel consumption. One apartment ran cool from the day that boiler was installed, and somewhere along the line the boiler was slightly over fired to compensate. The terrible near boiler piping didn't help any (no effective steam drying at all) nor did the added yet unnecessary condensate pump, F&T traps, formerly wet returns now dry and trapped, etc.



Due to space and cost constraints we went with the D248 of similar I=B=R output which nearly matched EDR. We installed a proper header and equalizer, eliminated the pump and traps, reinstated the wet return concept with Hartford loop. Its back to a traditional single pipe system.



Wow. With the Tekmar 269 set at its previous calibration, the building temp was 80 degrees and rising! The "cold" apartment is now the same as everywhere else in the building.



The client has long kept a log of run times to keep control of fuel use. For a typical 25 degree evening, the old boiler ran 32 minutes on, 37 minutes off.



After recalibration of the Tekmar and under the same weather conditions, the new Dunkirk runs 12 minutes and is off 47 minutes. The "steam established" sensor heats up in about 4 minutes now instead of 13 minutes on a hot start.



After clocking the gas meter with the new boiler and comparing it with past records, we've determined that the new boiler consumes about 10% less fuel while running.



Crunching the numbers and correcting for the differing number of cycles, run times and boiler gas consumption, the new boiler uses 44% of the old boiler's use during a day with the same weather conditions and achieved interior temperature plus the cold apartment now at 70 instead of 60 degrees. Same system. Better boiler, better piping.

We'll continue tracking this one throughout the season to see if the 56% holds true.



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II- On-topic digression:



This particular system seemed like it had been running "fine" even thought there were some "quirks." Yeah, there was uneven heat and high fuel bills. "That's just the way steam is." Right? So we changed the boiler and piping, removed a number of "improvements" etc. and achieved huge savings. I've gotten 50+% fuel use/DD reductions in a significant number of cases before this. Enough not to be surprised this time.



I've said it before, but I'll say it again: outrageous fuel consumption on a steam system should be viewed as a symptom of a problem somewhere, not a characteristic of the medium. It could be the envelope. Often its the boiler. Sometimes something is amiss in the heating system even though it appears "fine." Usually a little of everything.



But suppose we tore out the system and converted to air or hot water and got the very same 56% savings? The inevitable conclusion would be that steam heating is hopelessly inefficient. We would never have known any differently. The influence of well publicized steam-to-whatever conversion projects that have attained similar savings prevents most of us from considering the possibility that a well executed "sprucing up" of the steam system can garner similar results.



"BoilerPro" has a great article on some of the ways this can be done with single pipe systems and undoubtedly will continue with two - pipe methods. We use the slowest radiator vents available and vent the daylights out of the main. On two-pipe, we use orifice plates or Barnes & Jones adjustable orifice valves in order to perform a "virtual downsizing" of the radiation in old homes and buildings. Its really an elegant solution that prevents you from removing sections of radiators or changing radiators, etc. The icing on the cake is that radiator steam traps last forever if they necessary at all.

I look forward to BoilerPro's next articles on two-pipe downsizing and its effect on boiler sizing.



Oh. My cell phone pictures of the boiler room were lousy, but one came out okay- its a picture of a PVC drain line in the vicinity of the dry-fired boiler.



-Terry

Kevin_in_Denver_2

Real Estate savings

After considerable rumination on the subject, I have a conclusion that isn't based on system efficiency.



In an apartment building, the steam boiler and system piping should be removed and converted to a rentable apartment.



The heating and DHW for the building shall be done with one or two or three 98% efficient wall hung boilers.  Since they take up about 20 ft2 vs. about 400ft2, this is where you get the net rentable square feet.



The income from this extra apartment is $300-$1000 per month, depending on the city.  This income is more than the energy savings, which is now just an extra bonus.



Steam will never perform better than about 80% no matter how well it's dialed in.



I know we aren't allowed to talk about prices, so let's just say that I can get this done in Denver and the payback will be 7 years.  Nowadays, there is absolutely nothing better that I can do with my cash.  If I had to borrow the money, my rent + savings is higher than the debt service, again a no-brainer.

Steamhead

Nice work!

maybe you can take a camera with you next time? We'd love to see it.



Nothing "romantic" here, just a job well done.



Oh, and Kevin- given the typical basement boiler room, who would want to live or have an office down there? Even if it's renovated, it still has some of the characteristics of a dungeon. With the market the way it is, people aren't going to go for that. They'll go down the street to get a space with real windows for the same price.

ttekushan_3

135 square foot apartments

I never realized Denver had such a great market for 9'x15' apartments with one air vent near the ceiling!



Of course, I neglected to consider that 135 square feet near seal level expands when lifted to Denver's altitude. Imagine what these 12 suites could bring in at that elevation.



But then our steam savings might expand too :-)



-Terry

Kevin_in_Denver_2

typically 400 ft2

The apartment buildings with steam are usually "garden level".  The boiler rooms are a couple more steps down, but that makes for dramatic high ceilings.  All the boiler rooms I've seen are plenty big enough for a studio/buffet apt.  I get $510/month for one of these with just the one egress window. 



It's not in the heating contractors scope of work to recommend this, but all you apartment building owners should definitely "do the math". 

Steamhead

A couple more steps down

from what? Unless you're talking about a couple steps down from a basement apartment that has steam mains and radiators on the ceiling, you have to go down a lot more than just a couple steps for a steam system to work. Such a room might have high ceilings but it's still a dungeon. Oh, and check your local fire codes, one window might not be enough.



Here in Baltimore, all of our apartment-building customers are experiencing vacancy rates much higher than usual, and many have had to reduce their rents somewhat to keep their tenants (tenants "do the math" and tell them "why should I pay you this much rent when I can go down the street and get the same thing for $100 less per month?"). Basement or "garden-level" apartments are much more difficult to rent in these times ("why should I pay you this much rent for a basement apartment when I can go down the street and get an apartment with real windows for the same rent or a bit less per month?") so where they exist, they are often empty and have been so for a while.



From what I understand, vacancy rates are up in most places. You don't get any income at all from vacant apartments. Do the math.