CSI- Steam Boiler piping

TomM

Ripped the boiler out a couple of weeks ago, and finally could get a good pic of the weird return piping behind the boiler. 

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Check it out, it defies everything i've read in TLAOSH, and all conventional wisdom.  I'm pretty sure it was originally a two pipe air vent system.  That would date it to the mid 1920's or so.  I'm positive that there were never any traps.  Most of the piping, except for the lowest wet returns look to be original. 



Thoughts?  See pics-

Rod

Piping

Hi Tom -

     Interesting piping!   Is there a return form the main going to the left (from the bullheaded tee) ?    Could you post a picture of one of the radiators so we could see how they are piped?

- Rod

TomM

here you go brother-

the only picture with original valves is the one without a radiator.  Most of the valves were replaced, by myself, because they did not shut completely. 



The house is 3 floors, and all radiators are connected in parallel, riser and returns. 



Notice one of the valves is turned sideways.  Did that before i hung out here, i thought it looked cool. 



The picture with the Gorton vent is on the third floor, at the very top of the riser.  Works great!

TomM

also

i forgot to mention that the walls on pics 3 and 4 were studded out and insulated, that's why there is no radiator in pic #4, and the radiator is bumped out in picture #3.

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The only semblance of some kind of main vent is at the right of the return in this picture:

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But, i don't see any steam marks on the bottom of the wood floor, i'm not sure if there ever was a vent there or not.  That would mean that the whole system had 2 main vents on the ends of the returns (2 returns), but if that was the case, the upper floor radiator would not heat, or would only heat very very slowly.  It was originally coal though.

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TomM

yes

yes, from the bullheaded tee, it goes right and left, and there is a return dropping from both ends at the end of right and left mains.  

Hap_Hazzard

Countercurrent Drips

Those strange, meandering pipes from the mains to the wet return look like the drips they use at the end of a main that pitches upwards away from the boiler. It keeps the condensate from running back down the risers, or, in this case, from forming a puddle at the junction of the two main sections. The first part of the main is obviously pitched down, and then I'm guessing that the next section runs uphill, or it did at one time.



Of course there's no reason other than historical for their odd configuration, and they look to be joined together a little close to the water line, but they probably did the job.



So this thing had a copper header and all steel return piping?

TomM

something in the way

no, i thought about the steam seal idea before, but they all slope downhill. The copper header and boiler were installed in 1987, and has been soldered and resoldered over the last 25 years.  If anybody ever asks about using a copper header, just point them to that picture!

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 If the window was a coal chute at one point, then maybe the chute was in the way, and they couldn't pipe everything straight down.   that's a possibility.  looks to be knuckleheaded originally. -

The house was built in 1875, and originally had ductwork in the walls that heated the house via old school convection currents i guess.  It probably didn't work well, so the owners installed a coal steam system. 

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According to TLAOSH, two pipe air vent systems were out of vogue before the 1930s, due to the invention of the steam trap.  I always wondered why they didn't just put in one pipe steam, because they used twice as much pipe as necessary.  It is also really hard to balance because steam will leave one radiator, and enter another thru the backside. 

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Next door and across the street have gravity hot water systems.  They're pretty cool too!  They've been retrofitted with pumps, and my neighbor buddy is considering turning the pump off this season and seeing if it will balance better. 

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Anyway, i assume my system was knuckleheaded from the start.  Looks like my best guess.

ttekushan_3

I like those two pipe with air vent systems.

But I'm biased.  I don't like steam traps and I don't care for single pipe systems either (huge supply lines and counter-flow, etc.).



Just keep in mind:



-return must be wet.

-returns must NOT be vented.

-boiler should not be over-sized

-pressures must be LOW, use a vaporstat.

-pitch all return lines towards the boiler so they can't hammer when steam gets in them.

-build a proper header, a drop header is preferred.



If you control all these things, (remember that venting the returns will IMMEDIATELY fill them with steam, which you don't want to encourage), then a TRV  on the radiator inlet valve does a pretty good job of controlling the temperature.  You can even simply throttle the inlet valve to see if that will do. On the other hand, you might find that things even out pretty well if you do those things on the list.



Also consider an aquastat on the return main above the water line.  If steam gets there, you can use that to cycle the boiler in addition to the vaporstat. 



I've had great results doing these systems this way.