Vapor

Steamhead

boiler makers aren't putting much research-and-development into steam. I asked about this when I visited Weil-McLain's factory and this was the answer I got.

But think of the possibilities- Modulating Vaporstat or at least high/low fire, maybe larger steam tappings........ Hey Burnham, Columbia, Peerless, Weil-Mclain and others- ya listening?

I wonder about pulling a vacuum though, unless a pump was used.... The problem with naturally-induced vacuum was that with oil or gas, you often got vacuum before all the air was out of the system. This interfered with steam distribution.

But it is possible to build a thoroughly modern Vapor system that requires only a few ounces to operate. My concept would use cast-iron baseboard and orifices at the inlet valves to reduce the number of moving parts. A Vaporstat would work with the orifices to keep steam out of the dry returns.

Now all I need is a place to build this system.

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Mike T., Swampeast MO

Before WW-II every heating text I've seen said that vapor systems were certain to become the standard.

The benefits were incredible: inherent modulation, generally low temperatures, no problems with freezing, long-lasting components, etc.

Then the war. Afterwards labor was much more expensive. Ore (and recycled products) for good iron went to the war. The country was determined to reward their returning warriors. Many continued their education--something they would not have been able to afford otherwise--and went on to higher paying and less skilled (craftsmanship wise) jobs. Many came back to a family they had "planted" before departing and needed housing--NOW! Inexpensive but reasonable homes sprouted by the hundreds of thousands.

Instead of shoveling coal and tending the fire, most chose to use a modern system with electric thermostat that burned oil or gas. Blower motors were now common and exceptionally reliable. Air systems had always been significantly less expensive, so many chose these as well--particularly outside the NE area of the country.

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As I understand them, vapor systems worked by using the power of condensing steam to put the system under partial vacuum where steam could be produced at VERY low temperatures. A feedback mechanism linked the desired air temperature in the space to the draft of the coal fire itself. As the air temp in the space drifted away from setpoint more air was allowed to enter the system (raising the boiling point) and the draft was increased. While such might sound complex, it's a very sound and simple principle.

BUT, with gas/oil burning boilers attached to an electric thermostat there was no longer any way to change the size of the fire. Without this KEY part of the feedback mechanism, these fine self-regulating, modulating systems were reduced to essentially "normal" steam systems. They would either produce too much steam pressure under high vacuum or too little under atmospheric pressure.

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Jump to 2003. Modulating boilers that can mimic the old solid fuel boilers are being produced in ever-greater number and variety. When teamed with hot water systems originally designed for coal burning their efficiency and comfort are properly described as "awesome".

Why not make a modulating (even condensing considering the low temperatures possible) VAPOR boiler made to work with systems old AND new?

Such would address what I see as the major shortcomings of both steam and water systems:

Steam at atmospheric pressure is less efficient and more difficult to control than water (unless you're talking steam TURBINES that is).

Water freezes, expands and breaks ANYTHING when it does so. When you add compounds to prevent this you reduce its heat-carrying ability and resign yourself to careful monitoring of the fluid.

Mike T., Swampeast MO

Considering R&D for hot water boilers doesn't seem too great either I'm sure such for steam is essentially nil.

I do understand the economics involved, but it does irk me that the country that put a man on the moon and has the military technology to rapidly win any type of war save "guerilla" can't spend some of our money to actually reduce consumption of increasingly limited products coming from increasingly hostile areas.

Are ya' listenin' Big Brother? My firewall tells me you are.

Boilerpro_3

Hey Steamhead

Why not build this system in an existing two pipe system. Most have rads way too big for the load, so you could use only 80% (or less) of each rad. You could gut the old traps and install orifice plates in the supply valves. Then install a new smaller boiler sized to the orifice plate load and run your vaporstat. Also, since the boiler is smaller, the mains become oversized, reducing the pressure drop acoss the system, making it very low like on vapor systems. This is what I was thinking when I have said you can size a steam boiler at least close to the heating load rather than the radiation load.

Boilerpro

Steamhead

You could leave the traps in place

and still use orifice plates. The traps would be backup units in this case.

But I often see old Vapor systems with both traps and orifice shutters in the valves. Those Hoffman Differential Loop systems are a great example, and I think I have a diagram here somewhere showing how to reset them.

Now how about a modulating Vaporstat..........

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Boilerpro_3

Is a modulating Vaporstat really necessary...

If you down size the boiler, it will take a long time to reach the vaporstats high limit. I would expect that the thermostat will cut off the burner well before the vaporstat is satisfied. So you will get modulation inherent in the system.... similiar to a gravity hot water system with a properly sized boiler. The rads don't get to design temp until the boiler fires for several hours, but the stat is satisfied long before this happens.

Unknown

I've used them on two pipe with TRVs

High/Low gas burners in 1,000,000 to 4,000,000 BTUH vapor systems.

I set the low firing rate as low as I could keep it clean and still have draft, and the high at rated load.

The high fire was for the boiler and chimney protection, In that after it had steam pressure in it, the stack temp was high enough that it wouldn't condense. At 215° in the boiler, low fire didn't drop the flue temp very fast.

They would run at low fire for longer times than they ran on high fire. I ran them night and day, on an out door air sensor (WWSD) set to 65° F.

They ran like they were burning coal. The TRVs were GREAT!! I ran these on high fire up to 4 ounces, and on low fire above that, to 8 ounces. At a couple million BTUs!

Two pipe on a room thermostat would be a whole different animal. Adding vacuum on every cycle would chase air around a lot, unless you pump the air out mechanically.

My fear on closely sizing to the load the way you suggest, on a single firing rate boiler, would be that there would be hardly any room for error, and marginally undersized would be EXPENSIVE to run. In the real world, it would be up to the contractor in each case to get it correct. The theory is sound, though. I'd like to monitor the fuel use before and after.

Noel