vent problem

billygoat22

I have a two pipe steam system I'll be replaced the boiler on next week. 



was ordering pipe fittings for it and recalled the vent setup. I knew I'd be repiping the near boiler piping, but remembered that its two pipe. 



there's no alternating receiver like usual, but I think 5' of B dim might slide. Don't know if there was one originally, this boiler is only ten yrs or so old.  



there are three lines returning to the boiler room. two vent lines and a return, all dry. they ran all of them together into one vertical pipe back to the boiler. I know it can't vent right, and there's a single main vent like for a one pipe system. 



Can I find a vent big enough to vent all the rads and steam lines after separating the mains and return? Seems those vents on the receivers were pretty big.

Steamhead

Are the vent lines

actually the ends of the steam mains?



If so, they must each drop below the waterline before being connected to anything else. This keeps steam from jumping from one line to another.

Rod

2 Pipe Steam Vents

Here's a diagram of two possible 2 Pipe Steam piping layouts which I thought might be of help. You can see that as Steamhead mentioned the piping connects to the return below the waterline.

- Rod

billygoat22

vent for the end of line

I figured I'd have to drop the one return below the waterline to prevent that issue.  Right now they're all above the line, so the one lone vent will close when steam from the main hits it, sealing off the lines venting the rads. 



since they have traps on all the rads, do you still need air vents at the end of the lines, as opposed to leaving them open? I'd have to size vents for the lines and radiators if that were the case.

I can't recall if the original vents on alternating returns had thermostatic valves to seal them off ( steam should never have gotten to that point anyway, right?)

Rod

Vents

if there are multiple steam mains and multiple returns, the multiple returns shouldn't be connected until they are below the boiler waterline so that would necessitate that each of the multiple returns have its own vent.

While theoretically you could leave the vent pipe open, if a trap fails, you will get live steam blasting out into the basement. If someone hears the steam escaping and opens the basement door, they will see clouds of "smoke" (steam) and most probably call 911.  A main vent on the return prevents this and limits the mess the escaping steam can cause.

- Rod

billygoat22

thanks

I was wondering about that. Put it in today and seems to be working good. set the pressure low too, 2 psi max. 

Steamhead

How about

some pictures? 

billygoat22

pic-





hope it works, internet connection was being pretty balky. 



pulled plug out and used both tappings on top of boiler. Thing weighs just over 700 lbs. the two of us got it in with an electrotruck wannabe, thing scares me. tied it off to p/u truck just to be safe- slipped off 1st step and almost went down. cart makes good enough sled down stairs when you back up truck to let out rope.



Loved the lectrtruck last employer had. this one has some sort of stumps on a chain that barely grip the edge of step. this time the chain drive itself was slipping w/o the trigger being pushed and went off the top step.



85% afue on this one. got 12.5% CO2 and trace smoke. Higher than the forced air furnaces going in around here!

ChrisJ

equalizer

I'm not sure if I am seeing the picture right, but can an equalizer have a offset in it?