weird steam system

Steamhead (in transit)

nm

Al Letellier_9

weird steam system

Ok, steamers, I've got a good one for you: I have never seen a system like this one before and I'm just not sure how to proceed.The owner has asked me to quote whatever upgrades I would recommend, including changing the boiler, so I've done all the leg work, lots of research, measured connected load, and now I'm not sure about the system itseld. As Dan has always said " If something looks strange, slowly back out of the boiler room and look around, get to know the system".

The primary complaint is high heating costs and poor distribution of heat, along with DHW production problems (have that one figured out). Here are the details:
Smith Mills 17 boiler, hot water style radiators with coin vents, lever type restrictor or orifice valves, standard union ells on the outlets (two-pipe) and a connected load of 905 sq. feet
The main stumper is visual inspection of the system. One would swear on a box of vents that this is a gravity hot water system. It's even got a riveted American Radiator overflow tank in the attic, complete with sight glass.the killer is the water column on the left side of the boiler complete with sight glass, low water cutoff and pressuretrol. On the right side of the boiler is a vapor regulator, (long disconnected) and the 4 supplies and returns are 4". The heel of the 4 return ells that drop from the ceiling have been tapped with 1/2" pipe, and all are joined, along with the top of the water column and the vapor regular, into a common 1 1/4" header, vented by a Groton #1. Weird or what?
I can't help but think this was a gravity system at one time that was converted to steam. It's the only thing that makes sense to me, unless this mongrel of a system is something we've never seen in these parts before.
Our course of action will be to find out how the system works and try to get all the rads heating, then address the boiler (it's time has certainly come), but I'm a little uncomfortable with this one and how to set up the new boiler.
Any thoughts or experience with this type of system that you can share would be greatly appreciated.
Al

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mp1969

You Nailed it

You probaly have nailed it, some steam advocate probaly was caught in a time warp where he could not tell forward from reverse. A Munchkin or similar unit would be ideal for this large water volume system. Keep us posted!

MP 1969

David Sutton_6

Pictures Al we need Pictures lol seeing is beliving right

Steamhead (in transit)

I've run into one of these

it's not a matter of a steam freak not being able to tell forward from reverse. This was originally a gravity hot-water job that didn't work right, and circulators hadn't been invented yet, so they made a Vapor system out of it. The one I ran into had Sarco traps on each rad, and at one time had a return trap. Yours sounds like it might be set up as an Orifice system. Anyway, we vented the heck out of it with a bunch of Gorton #2 vents, corrected the pitch of a few pipes and it works great now.

I would NOT change this back to hot-water. It's been running as steam for so long, there might be weak points in the pipes and rads that would leak under the vastly greater pressure of hot-water- especially as it sounds like the system as it is is under-vented. See the Venting chapter in Lost Art to find out what can happen in under-vented systems.

Insulate all pipes and vent the heck out of them. I bet there are no vents on the steam mains, or if they do have vents they are way too small. There's a lot of air in those 4-inch pipes- use the Gill/Pajek venting charts which you can get on the Books and More page of this site. Figure on using a lot of Gorton #2 vents (note to Gorton: this system would probably be ideal for the proposed #3 vent!).

Since the rads are probably way oversized, orifice them down to the heat-loss calc results (thanks Boilerpro for this idea) and size the new boiler accordingly, using a 1.5 pickup factor.

Then stand back and watch how well it works.

Al Letellier_9

weird steam

Thanks, steamhead for the help. I truely had no intention of going back to water, but it was quite an eye opening for me. We do a lot of steam work locally and our reputation, good as we try to keep it, can get us into trouble from time to time, so it's great to have this resource when the occational "bump-in-the-road" comes along.
I'll do more research and follow-up on your suggestions and get with making "that old house" a lot more comfortable.

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Boilerpro_3

Thanks really goes to Mr. Tunstall

He passed the info along to me. BTW, I think the pick up factor was either eliminated or largely eliminated on the systems set up with orifices, providing further imporvement in efficiency.

Boilerpro