Trane vapor system questions

delta T

After some delays, we are finally getting going on the new steam boiler that I started to discuss briefly in this thread

https://forum.heatinghelp.com/discussion/165027/new-drop-header#latest

Originally I had thought to remove the old Trane orficed return ells, but hate to do so as they have no moving parts and will never fail. Also, it is a real PITA! There are only six rads that have the original Trane supply valves and return ells, the rest of the house is mix of convectors and radiators all with 17c's. We will be using a condensate receiver (see the other thread) and venting through that.

My questions is, Is there any reason not to just leave the return ells and take the dry returns from those radiators into an F&T before dropping into the receiver? I will then eliminate the possibility of steam getting back to the receiver, though there may be a chance some gets into the horizantal dry returns, given the orifices it cannot be much. Just to be clear, I am talking about the Trane vapor system described here:

https://books.google.com/books?id=b1lCAQAAMAAJ&pg=PA587&dq=trane+vapor+heating+system&hl=en&sa=X&ved=0ahUKEwj85tzD0ZLaAhVO-GMKHf6SC1AQ6AEIMzAC#v=onepage&q&f=false

Trane system starts on p. 586, the valves and return ells are described on p. 590.

Any one see any problems with just leaving them? Any special considerations on placement of the F&T? Should I just say screw it and go ahead and remove the ells?

any thought appreciated.

Steamhead

Those return ells do the same job as radiator traps. There is no need to change them. Also, there is no need to use an F&T before the tank- as long as your radiator return ells and traps are working, steam will never get that far. The F&T will just slow things down drastically.

If you're leery, pipe an aquastat in the line leading to the tank, wire it in series with the burner and set it to 180 degrees or so. This will stop the burner if steam reaches it.

Jamie Hall

What @Steamhead says. Don't even think of putting an F&T on -- it will mess things up considerably. Do put on a vapourstat, though, and set it to cutout at no more than 12 ounces -- 8 is preferable.

delta T

@Steamhead, @Jaime hall

Thanks! I do plan on a vaporstat, just kept having this vision of steam escaping through those 90s and banging away in my receiver.

I am still reading up on this Trane system, first one I have seen. Very simple and very cool! But since Im still wrapping my head around around it all, I want to get this picture right in my head,....the amount of steam that can escape through the top orifice in those 90s is just so small that it will condense in the piping very close to the radiator, or in the best case scenario, the radiator will condense all the steam before it even hits the 90, therefor as long as the pressure is kept in check, there is no need for a trap after those 90s. Obviously, if you start cranking the the pressure up it will cause all sorts of problems, but assuming very low pressures, is the above true for how this type of system will operate or is there a subtlety I'm missing somewhere....

Thanks again all, love learning about this stuff!

Got my header on today!

delta T

Also just want to verify that the old Trane no. 1 receiver is going to be meaningless on this system because of the pumped condensate receiver I am being forced to install. From my reading, it's function is more of a safety device if the coal boiler was over fired, water would back up out of the boiler on the returns as the pressure rose, and cause the float in the reciever to rise and close the vent, thereby sealing the system and allowing steam pressure to build on the return side and allow the condensate to flow back onto the boiler under gravity again. Yes?

Jamie Hall

On the Trane No. 1 receiver -- that's not a bad summary of what it was supposed to do. And did.

In the process, as you can imagine, it also limited -- to about 8 ounces -- maximum possible pressure difference across a radiator's orifice -- which in turn limited the amount of steam which could get in to just what could be condensed by the radiator and no more (assuming that the orifices were sized properly -- Hoffman systems and some others did much the same things with adjustable valves). Therefore, if you keep the pressure down, you just don't have to worry about steam in the returns.

Danny Scully

Who is forcing you @delta T?

delta T

@Danny Scully the house is, there is just not enough room, I looked at it 15 different ways, just ain't gonna happen, can't really expand the pit at all, as both sides are structurally important, and it would require pretty extensive reno to make it bigger.

@jaime hall, thanks, I learn more on every one!

JUGHNE

Delta T;
Condensate pump or feeder pump??
And reasons for one over the other?
Just curious, Thanks.

Danny Scully

Sorry @delta T I read too fast lol. I remember now from when you started the thread. Please send picks of pit and existing boiler. Pure curiosity. Is that’s the old coal shoot behind the new boiler?

delta T

Yep, boiler is going in the coal store lol. The pit is long, but narrow. They literally chipped out the side of the pit to allow for the return piping on the original boiler. New boiler will just fit front to back with about a half inch of clearance, will not fit side to side. Left side of the coal store (as seen in the pictures) is structural, some of the supports were removed briefly today (when i took the pic) and are back in place now.

@JUGHNE steel condensate receiver with a float activated pump because the owner already bought it and will not buy anything else, would really prefer a CI one but oh well.

Previous contractor bought the boiler and reciever, then did nothing for a YEAR, so we are taking over. Gonna temper the flow way down with a globe valve to protect from as many problems as possible.

Ill do an update on the the whole picture of the system piping, you guys will get a kick out of that, trust me

Wish me luck, I'll need it on this one!

delta T

So, I got to pondering last night, any reason I can't do this? I am pretty certain I have enough height to keep the original Trane system as a gravity return, but not the addition which is a mix of connectors and rads all with condensate traps, and an f&t at the end of the main. Diagram does not show all the rads, just generally representative of what I have, load on each of the mains is about equal.

Am I missing something? I have never seen a system with a mix of gravity return and pumped return, but I can't find a reason why this will not work, and then I can keep the Trane system as original as possible.

Thoughts?

delta T

I realize the venting detail is not right, I was in a hurry and brain farted. Mostly looking at having the combination gravity return and pumped return.