Steam heating hypothetical...(JohnNY)

JohnNY

Can you please check that attachment? I can't seem to open it.
Thanks.

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=290&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>

JohnNY

Low cost upgrade?

If a home increases in size, adding radiators and increasing EDR beyond the existing boiler's output, could simply adding water content meet the load without increasing BTU input?

I'm thinking the boiler would run a longer cycle, but not run out of water.

Am I way off?

Please see attached.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

don_52

It's interesting..

JohnNY,

I don't want to speak for anyone else.

Can you do it?

It depends on a few factors, other than water.

Give me a call @ 773-341-6453 and I'll hook you up with
a guy who is "better versed" in that particular subject
matter than I am.

We have had this conversation many times.

Regards, db

gerry gill

on a vapor system

you could probably get away with it..on a standard one pipe i'd say no..but you'd have to put an equalizer off the header to the top of the ''tank''.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

scrook_2

Seems to me

As you add radiation, eventually you'll have too little BTU's to make steam as fast as the radiation condenses it, regardless of how much water you have, so even after the pickup was heated you'd not have enough steam to go around.

It's about generating enough steam to match the condensation rate of the radiation. You don't want too much excess capacity or you cycle on pressure too fast, nor too little capacity or not all the radiators heat.

You might downsize the existing radiators though, (remove sections, move radiators to different rooms: smaller rads replacing bigger, minimizing the number that have to be separated and de-sectioned or replaced outright with a smaller one) assuming the space is over radiated for its heatloss then you'd have excess BTU's to support the new radiation, but that would be a lot of work! Perhaps radiator covers (if not currently installed) could be used to limit convection over the radiators (for while they're called radiators, they partly heat by convection) Even a small reduction in the output once they're initially heated would get you back to where you needed to be (again oversized radiation and improved structure insulation from initial build is assumed.

One supposes a hot water loop off the boiler would be another option, though if both zones call for heat at once you're back to square one, as you'll be robbing the boiler of BTUs it needs to make enough steam.

For your hypothetical case:
Are you that close to the edge now on gross BTU output?
Is the boiler (if oil) fired at max input already?
Are all mains and returns fully insulated already?

JohnNY

By hypothetical I mean....

...there is no case.

I'm not trying to address anything currently on my plate, just something that comes up now and then.

What if I added the storage tank and increased my manifold pressure by 10%.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Peter Groenewold

what about the heat loss calculation?

John,
You mention EDR of all radiators, I assume, but what about the buildings heat loss. You don't mention heat loss, and I feel it is a very important issue even for a steam system.

If the actual heat loss of the building is more than the boiler output, you won't be able to heat the building.

If the heat loss is less than the boiler output, you may be able to heat the building. I would say it now depends on whether you can overcome the iron on a cold start and still get enough steam to the radiators to overcome the heat loss. If no radiators have been removed, I'll bet you can.

Paul
A Real Good Plumber, Inc

Al Corelli_2

Limitation?

Even increasing the manifold pressure probably would not get you too far, as the square footage of heat absorption area will remain constant.

The mass of water in the tank is not subject to the direct application of heat.

I'd guess there would be some very limited improvement, until the ability of the heating surface to transfer heat was maxed out.

Thank you for making me think.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

JohnNY

"...the square footage of heat absorption area will remain constant."

I don't see why that's bad if we can change the run time.

Actually, isn't this kind of the same thing?:
(see page 16, Fig. 20)

Click here

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Al Corelli_2

Overfiring

If we increase the input too much, we'll just be heating the chimney, no?

Can't follow your link, problem with pdfs from home.

I'll re-read in the morning over coffee at work.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

Just to my thinking it seems

that it takes one btu to heat one pound of water one degree (F) between 32 and 212 degress and 970 btus per pound to take 212 water and turn it into steam. Adding water adds pounds so more BTU's needed, unless I am missing something.

Steamhead (in transit)

Might be on to something

since steam is a gas, if we keep the pressure very, very low- a few ounces- the steam will remain in an expanded state rather than a compressed one, and the boiler won't have to generate as much steam to fill the system. Oversizing the steam header will allow the steam to expand more then usual.

On a Kriebel Vapor system, one of the first boilers Gordo and I installed, we sized the boiler "by the book" then routed the output from the 3-inch drop header into the system's original 5-inch header and added our usual level of main venting. The steam flew into that system so fast we had to down-fire the boiler so it wouldn't short-cycle on the Vaporstat. Now the low-pressure gauge barely moves until all rads are fully heated. So we now oversize all our headers.

But remember- you can always down-fire a boiler slightly if you sized it by the book and it short-cycles. If you undersize it, the solution won't be nearly so easy......

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

ttekushan_3

Pick up Factors

Hello all-

I've attached a drawing that I use to explain the existence of a pick up factor in steam heating. This also gives the rationale for staged firing and why undersized boilers can cost a fortune to run.

I hope it helps. I'm not sure its ever helped my explanations:)

-Terry

Unknown

How low can you go ?

I know we're always seeing steamers oversized , sometimes grossly . But have you ever run across a steam boiler that was undersized ? By alot ? Did it still do the job ? And did it burn more fuel doing it's job ?

I remember one a few years ago . We were there to add a zone off the bottom . Total sq. ft. of radiation was over 400 , uninsulated mains too . The boiler had an output of 283 . Homeowner told us it heated the house just fine .

ttekushan_3

attachment

Some browsers download it to wherever you have files go. But as it would turn out, I forgot to check how large it was. So I reduced the file size and converted to jpeg.

This should work.

-Terry