Return line setup

Wvega123

I have a return line which goes up vertical (see pic). How does condensate make its way up the line? The line cannot be changed due to slope. If this cannot be redesigned then I just need to know what should be the necessary maintenance. My guess is the line should be emptied during the off season to prevent rust in the line. Thanks for your feedback.

Intplm.

The condensate does not make its way up the line. Steam does.

Condensate builds as it travels through the piping and changes from a gas (steam) to a liquid (condensate). This happens in the same pipe. It drains back to the boiler from the horizontal pitched piping.

It appears from your picture that this has been piped this way for a very long time. If there is nothing wrong with it, leave it alone.

Intplm.

And, this pipe is probably a dedicated return. Draining condensate back to the boiler.

ethicalpaul

Any time you have a buried return, you are going to, by definition, have a vertical climb that is difficult to keep clean. I would be concerned about clogging due to gunk collecting in the low area just as much as I'd worry about corrosion. Every wet return corrodes.

You propose emptying it during the off season. How would you do that? And are you sure that would result in less rust?

If it were me I'd fill the boiler to the top of the gauge glass every spring, mark the level on the glass, and if the level is lower in the summer, then you know the line is leaking. At that point, replace it with copper, hopefully above slab if you can.

Or if you don't like to wait for it to fail, replace it this summer.

I'm curious to see what the people who replace these pipes for a living have to say.

Jamie Hall

What's that connected to at the upper end? Looks to me at first sight like an ordinary drip from either a steam main or a dry return. As @Intplm. said, condensate doesn't go up it — it comes down. And will stand at a level in the pipe corresponding to the pressure differential between the boiler and wet return to which it attached at the bottom and whatever it is attached to at the top.

Wvega123

Thanks all for insightful comments. I didn't think about condensate in vapor form so that makes sense to me. The vertical line you see is for an air vent. The system was operating at a pressure as high as 5-6 PSI. I added a big mouth halfway of the 80 feet length and three gorton #2 at the end of the 80 ft line. I also lowered the pressuretrol cutoff PSI to 2.5. Ever since I no longer hear that vertical air vent hiss and the PSI stays primarily below one but does work its way up to 2 before the call for heat is cancelled due to indoor sensor (heat-timer). I could replace the return line with cooper just need to decide if that's a wait till it leaks or be proactive. I will open the drip leg in the off season and see the condition which will inform wait or replace.

EBEBRATT-Ed

That pipe is a wet return. I doubt there is any steam in it or air for that matter if the return goes back to a boiler.

If it goes to a condensate return tank or to a boiler on a lower level then that is a different issue

Wvega123

That return line is a dry return and as you say it goes down to the boiler room and into a condensate tank that is open to the air. Maybe it had steam in it in the past when the pressure was high but now it should be liquid condensate.

Long Beach Ed

My guess is that this returns condensate to a receiver, and that standpipe vents the return.

Since the pipe dips underground at some point, I'd keep an eye on water usage for leaks. It looks to be about 70 years old (1950's?) so it may still have some life to it.

There's no maintenance needed, except that the vent is kept operable.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1846698#Comment_1846698

I thought it was a wet return as it seemed to be buried in a slab. I'm glad to know the truth!

EBEBRATT-Ed

The way its piped looked funny to me which is why I suspected a condensate tank or a boiler at a lower level.