Rerouted Condensate Piping

michaelmiracle

I am working on a 1924 steam heating system in a school in Denver. I wrote another post about replacing F&T steam traps. I want to see what you all think of where 2 of these traps are in the system. (there are 2 more on a different section of return, also in the basement.) It appears a radiator was added sometime in the 60's possibly. The condensate line was rerouted to include this radiator which is below the steam and return lines. Attached are photos. 2 traps are in this area. One is after the radiator. the other is before the drop in the return line. It seems that the condensate will just gather in this area and fill up enough to return through the higher return line, but always stay full of condensate. Any thing to do about this other than close the steam valve to the rad. It is warm enough down there and it isn't needed. What kinds of problems could it be causing? I don't see that I can remedy it by moving pipes, above my skill level and the school doesn't have the money to invest in that. Too many other problems with this system that are more pressing, like a 30 year old boiler and no insulation on the pipes running through other parts of the basement.

EdTheHeaterMan

And water flows downhill?

michaelmiracle

not sure what you are asking. The boiler is to the right as you look at the picture.

109A_5

Hello @michaelmiracle,

Any vacuum pumps in the system ?
Did you drain that part system shown before the trap cover was removed ?
When the cover was removed from the trap on the left did it drain part of the system, not just any water in the trap ?

I would think everything below the return on the right side would eventually fill up with condensate if no vacuum pump. If the system builds pressure it may push some of the condensate along when steaming if there is a pressure differential. The rest just seems to look like gravity return. Any boiler room pictures ?

Mad Dog_2

That's a Swing check, not a "backflow" to be on the same page.  Mad Dog 🐕 

michaelmiracle

Thanks for the correction on the Swing check. Any vacuum pumps in the system ?
"Any vacuum pumps in the system ?"
NO
"Did you drain that part system shown before the trap cover was removed ?"
YES
"When the cover was removed from the trap on the left did it drain part of the system, not just any water in the trap ?"
YES, a lot of water
"Any boiler room pictures ?"
YES, what exactly are you wanting to see?

109A_5

Hello @michaelmiracle,

Just trying to get a feel for the system and if the part of the system in the beginning of this post had any chance of working correctly or it was just knuckleheaded and then basically abandoned. A vacuum pump can be used to 'lift' condensate to aid in moving it along, when done correctly. Having the radiator below the return pipes can work if there is a proper way to remove the condensate, so the radiator is not constantly flooded.

I don't think the F&T traps pictured are doing much if they are always fully flooded.

Does the return leaving the first picture to the right stay at the same height as it is when it comes out from behind the dryer ?

109A_5

Hello @michaelmiracle,

I'm thinking that coil (the Radiator) is to heat another area, through the wall maybe, not the room the camera was in to take the picture, is that area warm enough ? If the F&T Trap drain pipe is repaired and the valve is open any condensate may drain through the coil and not be a problem. See picture.

michaelmiracle

The rad definitely heats that room, behind the wall is a crawlspace. It is much newer than the other rads in the building. I'm in the process of changing the traps so that's why the disconnect you see by your "?'. Much of the piping in the crawlspace behind the wall has had the asbestos insulation removed and is bare, so the basement can get very hot. The room you see is a cafeteria.

"Does the return leaving the first picture to the right stay at the same height as it is when it comes out from behind the dryer ?"
The return line stays at this height you see here, then drops straight down in the kitchen and comes out behind the dryer at the lower level.
I just read Dan's post on F&T traps where he says if the traps aren't in place the boiler room will be a sauna because of the venting at the condensate pipe. The boiler room is indeed a sauna getting to 100 degrees. The pipes in the boiler room are insulated. Just outside the boiler room and traveling through the crawlspace (150') the pipes are uninsulated so it tends to be very hot down in the whole basement.

"Having the radiator below the return pipes can work if there is a proper way to remove the condensate, so the radiator is not constantly flooded."
Are you saying this is not proper as is, or do I need a pump to move it through the lower pipe section?

109A_5

Hello @michaelmiracle,

Do you have the link to "Dan's post on F&T traps" I'd like to read it to see if it is applicable here with the present state things are in. There has been a few discussions here on the Wall about not getting much heat from condensate water. If the heat from that coil (the Radiator) is not needed, that is fine, I just wonder why it was put in later. Also the cabinet does not seem to have much ventilation into that room unless it is open at the top and bottom, which I can't see, and why the apparent gap in the wall the length of the top of the assembly ?

What does the electrical thermostat stuff in the picture control a zone valve or maybe a fan ?

F&T Traps that are constantly flooded IMO can't work correctly (its like they are not there) how do you vent out the air to let the steam get into the radiation devices ? Where air is steam is not. I suspect, since I don't see any venting, hence trapped air, the boiler runs way too much trying to satisfy the call for heat.

If condensate is trapped below the line I drew the F&T Traps are constantly flooded so they are basically just pipes with useless stuff in them, how can the air get out ? The condensate will pass via gravity like a trap under a sink (which keeps the sewer gasses on the correct side, no air passes through). I would suspect all the radiators connected to that part of the system work poorly.

109A_5

Hello @michaelmiracle,

michaelmiracle said:

The return line stays at this height you see here, then drops straight down in the kitchen and comes out behind the dryer at the lower level.

Since it looks like that part of the return system services at least 4 radiators. If the pipe heights are correct for pitch and their relationship to other equipment, I would just move the return pipe down as pictured and make sure each radiator has some sort of working trap. No more flooding that part of the system and not blocking the air removal path, like a dry return.

michaelmiracle

Dan's post:

https://heatinghelp.com/systems-help-center/what-you-ought-to-know-about-f-and-t-traps/1) The Only Time You Need F&T Traps Is When You Have A Condensate Pump Or Dry Return Lines.

"F&T traps keep steam from passing by. They are normally closed automatic valves that work like ballcocks. When they're working, they stop steam dead in its tracks.
You need them if you have a condensate pump because condensate pump receivers are vented to the atmosphere. Without traps, you'd turn the boiler room into a sauna. You can't plug the receiver vent because the receiver could explode. I've seen this happen. It's not pretty."

I do have a condensate pump in the boiler room with a vent. Probably not the steam room he is talking about. My mistake, I wasn't clear in my communication so you can ignore my ignorance there.

Yes, My suspicion is this is flooded below the return line. I can't drop the line to the lower level because there is an elevator, doorway and halls it has to cross at the right of the picture.

I haven't investigated that thermostat and how it works, but it is for that rad.

The Rad is vented at the top to the room. The panel with the 2 handles in the front is meant to slide up to reveal the rad, but painted closed right now.
I did buy the new internals for the traps. I'll put them in and most likely keep the radiator shut off from the rest of the system.
Thanks so much for your help. I'm continuing to learn.

109A_5

Hello @michaelmiracle,

michaelmiracle said:

Yes, My suspicion is this is flooded below the return line. I can't drop the line to the lower level because there is an elevator, doorway and halls it has to cross at the right of the picture.

That complicates things. If the radiator functionality in that room is to be retained. A means to move the condensate and the air is needed so the radiator and the F&T Traps are no longer flooded and the air can move out so steam can enter. If the radiator is abandoned the system could be restored to how it originally was. However apparently there was a need for the radiator at some point.

From that room to the Right all the way back to the boiler room are there any other radiators connected to that return ? How does the steam get to the radiators(?) that the returns on the very Left are for ?

A condensate pump could be put in that room (not a plan I like). The air is easier to deal with than the condensate. A vacuum source in the boiler room can be utilized to move (lift) the condensate and evacuate the air.

If you are going to be maintaining this system for a while, you may find this book interesting, there are others too.
https://heatinghelp.com/store/detail/the-lost-art-of-steam-heating-revisited
Many YouTube videos too.

dopey27177

Not doing any short cuts or creative piping the best way to handle the discharge of both traps is to install a small condensate pump. And run all the low condensate piping to the condensate pump.

A quick temporary fix is to install a check valve in the discharge side of the steam traps and the condensate line to the left. Since you are working in a school the steam system pressure would 2 PSIG or more. The steam pressure at 2 psig will lift condensate water about five feet enough to reach the elevated condensate return. This fix will have some banging or ticking when the check valve open and close.Tell them they need a small condensate pump. That way all the low condensate lines can go to the pum, no problems that way.

Jake

michaelmiracle

thanks for the responses. That may be what I need, a quick low cost fix. This radiator isn't needed as the basement is quite warm. A condensate pump to move it through might be a good answer.

From that room to the Right all the way back to the boiler room are there any other radiators connected to that return ?
NO
How does the steam get to the radiators(?) that the returns on the very Left are for ?
Good question. I have to get into the crawlspace and trace the pipes. When the elevator was put in some of the pipes were routed around it so it's a mishmash under there.

this return line is in the middle of the building, it serves the center hallway above it, (and maybe something else, I can't be sure). But in that hallway are only 2 radiators. You can see the lines going up to one of them above. The other rad isn't critical. There are no shut off valves on the radiators, just TRVs that I could turn all the way down to stop the steam and therefore the condensate. That may be the way I go since it is the lowest cost and least impact as those radiators do not provide needed heat to their areas.

But I do have a better understanding about what's happening in this section. I have the book and watched the videos. That is what brought me here. But I hesitate to change what I don't really understand that a plumber did before me. I can see now that this was not the best-thought-out addition.
Thank you again

109A_5

Hello @michaelmiracle'

"From that room to the Right all the way back to the boiler room are there any other radiators connected to that return ?
NO"

If this it true, I would use vacuum from the boiler room to return the trapped condensate, the pipes would need minimal modification to accommodate this. Folks seem to not like vacuum, just saying.

Personally, I don't like the idea of a condensate pump in a public area.