Old coal fie with gas burner replacement

SM

I am in the process of buying a home (bank foreclosure) that has this old boiler in it. The first thing I am going to do is tear it out. I do have several questions, and I am sure this thread will create more questions as it goes. I have Dan's book "The Lost Art of Steam Heating" so today I went and measured radiators and took pictures. Came up with 536 EDR (128,000 Btu’s) so figure I need 200K input. You tell me if I have the right terminology, two pipe system with wet returns, no Hartford loop (traps in both return lines down low), I would say that it does not have a header. Two pipes come straight out of boiler and take off. I do not see a F+G trap. Should I on a wet return?

The new boiler and am figuring on piping with a header and then Teeing off in to the present mains similar to picture on page 55 of Dan's book. Should I use a drop header? "A" Dimension would be from bottom of header to water level? And should that be 24"? Will pipe a Hartford loop, Will I need an F&G Trap? Tell me what I might be forgetting. I have never replaced a steam boiler, but have had Dan's book for 2 years, reading thru it from time to time.

What is a good boiler? Economical! I bought this house to resale. Crown? Weil McLain?

Thanks for all the input I am sure you can give me.

Steamhead

What you see was typical

in those days. Old "snowman" boilers like that one rarely had Hartford Loops. Sometimes they did have check valves in the returns. The new boiler must have a Hartford Loop, and in most cases (but not always) the check valves should be removed. The exception to this is on Vapor systems with Return Traps or Differential Loops.

You say this is a two-pipe system. Are there two pipes connected to each radiator? Are there air vents and two shutoffs on each radiator, or do they have a single shutoff with no air vent and a trap or other device on the return connection?

Are the return lines wet, dry or both? Are there any ancient devices in the return piping near the boiler? Have you found any manufacturer's info on any of the system's hardware?

The answers will determine what type of system you have, and how you should set up the piping around the new boiler.

Regarding steam boilers- a good boiler is a good boiler. I doubt you could go wrong with any of the major brands.

SM

Radiators

Radiators have a valve up high on the one connections and what appears to be a trap looks like the drawing on page 142. I saw the return vent up high in the ceiling joist.

How can I tell if the returns are wet, dry or both?

Steamhead

That's a Vapor system

Almost all two-pipe systems with traps were Vapor. You can read more about Vapor in chapter 15.

Since you have an overhead return with a vent, that is a dry return since there is no water standing in it. This return handles air and condensate from the radiators. The air goes out the vent and the condensate (water) returns to the boiler. You may also have a wet return, which runs below the boiler water level and only handles water returning to the boiler.

The steam main needs to be vented too. You may find a main vent at the end of each steam main, or a trap connecting the main to the dry return. If there is nothing there you will need to add a vent.

Look for manufacturer's info on the original radiator valves and traps. This will give us a clue as to who made your system.

SM

What wold it take to convert this thing to a hot water system?

Obviously would need a heat loss calculation. Does have newer double pain replacement windows in it. Would have to pressure check the system for leaks, and remove the traps on the raditors. What else am I forgetting? Just seems that the steam boilers are not as eff. as the hot water boilers made today. Would you figure a pickup factor for hot water. The BTU's/ EDR is 170 instead of 240 correct?

Steamhead

I wouldn't do that

We get at least two such questions a month here on the Wall. There are many reasons not to try this unless you want to be married to it......

First off, hot-water requires at least 12 times the pressure that Vapor does. Vapor systems run at less than a pound, while hot-water needs at least 12 pounds- and that's in a two story building. If there are any weak spots in the system, the higher presure will surely find them. This might happen on the initial pressure test, or after the job is finished. I've seen this and it's not pretty.

Some people try to justify this type of conversion by citing the higher efficiency of condensing hot-water boilers. But unless the rads are so oversized that the water temp rarely exceeds 130 degrees or so, a condensing boiler won't run in condensing mode except on the mildest days. There goes the efficiency advantage.

For a discussion of more pitfalls, go here:

http://www.heatinghelp.com/newsletter.cfm?Id=22

Vapor systems were the Cadillac of heating in their day, and are still some of the best out there now. The most cost-effective solution here will be a new, properly-piped steam boiler, proper air venting and new trap elements (you don't have to replace the entire trap body in most cases, just the insides). I know of one case where a Vapor system was converted to hot-water, never worked right, and was converted back. You have a unique opportunity to learn Vapor- make the Dead Men proud!