Venting a low return in the spaghetti factory.

Gateacre

Hey everyone. Up front, 1890s commercial property, 2 pipe steam. 2 condensate return tanks remote from the boiler room, 1 in the boiler room and a boiler feed tank. There are 2 boilers. One is abandoned in place and sits in a pit about 3 feet below the floor of the current boiler. For a time, it was maintained as a backup meaning condensate could be routed to either. This resulted in some unorthodox return plumbing that I refer to as the spaghetti factory and this sets the stage for my current situation.

There are a handful of rads on the boiler level of the building. They are served by two 3/4" returns that disappear into the concrete floor and emerge in the boiler room as a single 3/4" copper pipe (I know). It's the ability of this return to effectively vent air that I'm concerned with.

Visual aids incoming.

So as we can see, anything (liquid or gas) needing to exit that copper pipe must pass through a permanent water seal. Will this prevent or seriously slow the venting of the rads that use this return? Being a former coal burner with no mains venting, this whole system is already slow to heat.

If I were to simply sweat in a Tee (in place of that compression coupling perhaps) and extend a few feet of pipe up, left open to the air, would it make much of a difference? I'd turn down the top of the pipe to keep anything from falling in.

Thoughts?

delcrossv

You'd have to do it before it drops into the water filled pocket.

Gateacre

https://forum.heatinghelp.com/discussion/comment/1841615#Comment_1841615

Yeah. It's tight quarters but anywhere before it 90s down to the floor should be fine right?

Gateacre

https://forum.heatinghelp.com/discussion/comment/1841615#Comment_1841615

As it is, will air be able to vent through that water trap?

delcrossv

https://forum.heatinghelp.com/discussion/comment/1841649#Comment_1841649

Nope. Unless the pressure is high enough to push the water out. So,under normal operation, no.

delcrossv

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1841649#Comment_1841649

Nope. Take @delcrossv 's suggestion. Keep in mind that the fact that those radiators aren't vented doesn't mean they won't heat — they will, a little, and very slowly, which can be misleading! They'll do much better with the vent.

delcrossv

https://forum.heatinghelp.com/discussion/comment/1841624#Comment_1841624

Correct. As long as it isnt flooded elsewhere.

Gateacre

https://forum.heatinghelp.com/discussion/comment/1841655#Comment_1841655

Thanks, Jaime. This is a sanity check as much as anything. Unfortunately the techs who installed the new tank as well as the new boiler were less than receptive to my suggestion that the existing piping might cause issues. Their work on the boiler install was pretty good and given that they're basically the only game in town, I can't afford to jeopardize the business relationship so I bit my tongue. There's a ball valve at the end of that copper that must have been used to direct condensate to the appropriate boiler at one time. It allows me to drain down and leave that return open to the air. Of course this lets any new condensate to escape to a drain but a test cycle with the valve open let all the rads heat quickly and silently. Several of them have single pipe vents installed which were spitting rusty water onto the carpet. This stopped with the valve open. But apparently "that pipe is for condensate, it's a vapour system, air has nothing to do with it. You gotta get off the internet".

Sigh. This forum has been a godsend.

delcrossv

https://forum.heatinghelp.com/discussion/comment/1841757#Comment_1841757

Lol. Guess the air goes through a wormhole into another dimension. 😅