Steam Range tank questions (ME)

ScottMP

If you can go back and find the post I did about a Steam replacment job there was some GREAT responses from Steamhead, and Noel, all about this.

I believe the post was " And now back to Steam S Milne".

I agree with Dan you need a boiler feed tank.

Scott

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Mark Eatherton1

Piping and sizing questions..

Wallies, I'm getting ready to replace a one pipe steam boiler that had a massive, high water content boiler in place. I obviously cannot replace it with the same thing because they don't make them like that anymore. It was recommended by a trusted supplier that we install a 40 gallon low boy electric heater tank on the condensate return. Short of reducing the 1-1/4" condensate return to 3/4" to get through the tank, do you guys have any good suggestions?

My initial thought was to remove the element, and pipe a branch off the condensate return into the tank, and install a tank vent to as high as the dry return. This way, the tank becomes a FAT spot on the return.

Open to suggestions.

TIA

ME

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John@Reliable

tank

very low cost tank too!

DanHolohan

Adding water

to the return won't make it go back into the boiler any faster, Mark. Think about it, if you increased the 1-1/4" return by 51 feet you'd be adding the same 40 gallons to the system, but it still won't go back into the boiler any faster. The only motive force that can put water back into the boiler is gravity, and all you have going for you on a gravity-return system is the "A Dimension." It takes a drop of water in that space to move a drop of water back into the boiler. It's like a scale and a fat spot in the return makes no difference at all. I think you may need a boiler-feed pump for this job.

Unknown

here it is....

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=163&mc=56

Mark Eatherton1

Thanks guys!!

A vapor stat it is!

You guys are the best.

ME

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Boilerpro

Right Idea, wrong piping

I believe what you are looking for is in the post Back to steam heat. If you take that tank and equalize it with the boiler by taking apipe off the top of the boiler, it should add its volume between the min and max waterline to the boiler. You's probably get more water to work with if you turn the tank horizontally and center the tank in the middle of the working water level of the boiler. May get a chance to use this idea sometime soon. Hydrotherm has some diagrams showing this...no need for a feed pump just use the force of steam, just like in the old days.

Boilerpro

DanHolohan

I've often wondered

what this method does to combustion efficiency (lots more volume near, but not in, the boiler), and also the exposure to liability it places on the installer if that tank isn't ASME rated, as the boiler is rated.

Boilerpro

I suppose..

if the tank is well insulated, like the indirects we see around, the efficiency is probably pretty good. A condensate feed pump, I would think, should have the similiar efficiency characteristics, since it is also water near, but not in, the boiler and its not insulated. The combustion efficiency may go up, I suppose, because the water level will probably stay higher in the boiler, providing better heat exchanger efficiency. The boiler may come up to temp a little slower( because of steam condensing on top of the tank water)...longer burner cycles.... but probably not much different because the tank will only feed the boiler when the water level drops. Definitely may want an ASME tank in this app. to CYB.,even thou water heaters are rated at much higher pressures than 15 psi.

Boilerpro

Unknown

I have concerns about water line stability

Would you have it piped such that the equalizer is parallel to the tank or through the tank? Would the return water pass in and out of the tank, or would the tank tee into the return? Would the steam line into the tank come off the top of the header(dry) or from the side, bottom, or end?

I think that if the tank is cooler than the boiler by much, the colder, denser water in the tank could push water up toward the boiler outlet as the boiler steams fast and hard during warmup, and perhaps prime water up into the system.

Have you done this yet? Does it work for you?

Noel

Boilerpro

Haven't done it yet

but I find it very interesting. I suspect you'd want to take an equalizer right off the boiler, since the pressure in the boiler is probably higher than out in the header. The one I've seen I believe was hooked up right into the boiler both above the water line and below, like the 1 inch piping for a Lwco off the side of the boiler. Supply and return piping remained separate. Could not really tell how well it worked becaue teh returns to the boiler were not installed correctly. I imagine only a small pipe would be necessary since very little steam would be moving through the pipe(just that condensing on top of the water). Your idea about the heavier cold water in teh tank pushing down on the hotter boiler water is interesting.

Boilerpro