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Possible clogged wet-return

mattm Member Posts: 40
I posted a week back about a corroded wet-return that had been pitched wrong. When we replaced the pipe, there was water that seemed to be pooling. Could still be pitched wrong, but I got to reading about wet returns and I am worried that the wet return is clogged. I'm in the process of adding insulation, replacing radiator vents and balancing the system in general. Don't want to mess around too much when it is 5 degrees out though! Anyways, a couple questions:

- Should the wet return have a vent (none of the mains vents are working)?
- It looks like there was a valve in place to flush the wet-return, but nothing is attached where it comes out of the floor? Am I crazy?
- This is a finished-ish basement, I don't want to jackhammer the floor to replace, could I just run the pipe across the middle of the room and then down and wrap some caution tape around it?
- The boiler has a high water level. If you drain it to the half-point on the sight-glass, then it just returns to a high water level. I assume that water is percolating back through the return after the LWCO comes on.


  • Jamie Hall
    Jamie Hall Member Posts: 23,270
    Wet returns can and do clog. If you can find a way to open one end and flush it out from the other with a hose, it will be worth it.

    In warmer weather, perhaps?

    Is that pipe branch coming up out of the floor plugged with anything? It's hard to tell in the photo. It almost looks as though it had water in it.

    Another thing about wet returns buried under floors. They have been know to leak. Frequently. Could yours be? How much water do you have to add to the boiler, and how often? Shouldn't be more than a gallon a week at the most.

    And yes, so long as the wet return pipe is kept below the water line in the boiler along its full length, you could run a nice new one anywhere you like.

    And no, wet returns do not need vents at all. Steam mains, however, do, and it would help your system if yours had them.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattm
    mattm Member Posts: 40
    Thank you Jamie, that clarifies a few things!

    I was mistaken, that main vent is on the dry return. I am worried that the water is reaching the dry return, so I don't know if I should replace the non-functional main vent at the end of the dry return in case it starts leaking water.

    With respect to wet returns - is there a minimum length that the wet return should be? The location of the wet-return is a pain as it is buried in concrete under a finished floor. I could extend the dry return, but risk our hitting our heads any time we go to do laundry, or could move everything around.

    You are correct, that pipe branch coming out of the floor does have water in it! It supposed to be closed (the handle was buried in dirt). Since there is water there, I assume it is not fully closed and leaking slight. There is also no gate valve, so if I opened it, I would presumably drain the boiler.

    We have an autofeeder, but I didn't see anywhere that it would tell me how much water it is putting in.

    When it is fully cold, it looks like the boiler is a bit flooded. When it is cycling frequently, the water level is simply high. Presumably, the water is taking a while to percolate back through the wet-return, and also leaking out.

    Is there any way to solve this without running whole new wet-returns? Any alternative means of piping the return?