Water spurting out of a main vent opening

pnm2

While running my boiler with the two main vents unscrewed (in order to time when the steam came out to determine the amount of venting required), I noticed that, instead of steam, water was spurting out of one of them.

When I brought it up on this forum, it was suggested that most likely the boiler is "carrying over" water into my main(s), perhaps due to an error in the installation of my near-boiler piping.

In order to verify, I sent photos to the boiler manufacturer, and they replied that, while the near-boiler piping, indeed, does not match the drawing on their manual, it doesn’t necessarily mean that it will not work and it does appear to them as if the installer may have been confronted with some existing piping issues that they needed to work around.

Before I contact my installer to further investigate the matter, I'm wondering if anyone has any other ideas as to what could cause this water-spurting from my main...just so I know I've exhausted all the troubleshooting within my capabilities before calling in a pro.

Thanks in advance!

JUGHNE

IIRC, your vents are on the end of the "dry" returns at the boiler, yes?
You could raise them up on riser pipes to avoid the water somewhat.
But they drop down to the wet return piping at the boiler, is that piping clear so that the water does not back up to the vent area?

EBEBRATT-Ed

@pnm2

Your problem is one of two things:

1. Improper near boiler piping
2. Surging or bouncing water level

This is assuming that all your piping is pitched properly

ethicalpaul

Did you tell them it was shooting water out of the main vent ports?

It was nice of the manufacturer to defend the incorrect piping. I guess they don’t want to hurt the tender feelings of your installer, but I’d rather they gave the installer the suggestion that he should pipe it correctly so their boiler would work correctly.

Jamie Hall

I'm sorry, I don't recall -- but are these vents on a dry return, or are they on an extension of the steam main? If they are on a dry return, it is possible that the boiler pressure is excessive. You would need 28 inches above the water line for each psi of boiler pressure.

If they are on a steam main extension, of course, this is not a factor.

KC_Jones

Wait, so yours almost perfectly matches one of their own diagrams clearly labeled “WRONG” and they are ok with it?!

I've heard the manufacturer sides with the contractor because of worries about losing business, but now they are actually contradicting themselves.

It’s wrong, no defense of that as near as I can tell.

Sad.

Try this technique.  You have what is known as a colliding header, I posted a picture of what happens, from the Peerless manual on your other thread.  Send them that picture and use the term colliding header and ask if they are ok with that as that’s what you have.  Also mention they clearly show that as being unacceptable in their own manual.  Then ask how they could say it’s ok.  Most likely goes nowhere, but it’s all I can think of.

As far as existing piping issues, that’s all supposed to be ripped out to facilitate proper piping and shouldn’t be considered in the discussion.

pnm2

@JUGHNE When you ask if the wet return piping at the boiler is clear, do you mean is it not clogged? I don't know how comfortable I'd be trying to take it apart to see, but maybe I can get a pro to look into that.

@EBEBRATT-Ed I did notice while inspecting the glass gauge that the water level appeared to go up and down quite a bit, so maybe you're onto something with the "surging or bouncing water level" suggestion. Any thoughts as to how to resolve that?

@ethicalpaul I did send them a picture of that vent as well and let them know that water was spurting out of it, and that that's what led me to look into the installation.

@Jamie Hall The mains are at the ends of the dry returns, on the top of the "elbows" (I believe that's the term?) that then dip down vertically to the wet returns. Upon measuring the height I did notice that 28" down from the vent from which the water is spurting (itself at least half a foot lower than the vent that's fine) does seem to hit the top of the water gauge (right below the top spigot) -- an area where the water level rarely rises but perhaps sometimes does.

After reading Dan Holohan's book, I had set the pressuretrol to a range of 1/2 to 1-1/2 psi, but if it's 28 inches per PSI maybe I need at least 42"?

If so, would raising the vent with an extension be a solution, or is it the dry return pipe itself that's supposed to clear the 28"/PSI height?

@KC_Jones Maybe I'll try that...unless extending the vent does indeed solve the issue.

Jamie Hall

The dry return itself needs to be above that 28" per psi height. Which is an argument for a vapourstat and lower pressure!

pnm2

@Jamie Hall Could lowering the maximum PSI from 1-1/2 to 1 be a viable solution? Or is that too low?

Barring that, I suppose I could try to have the dry return raised? Though that sounds far more involved.

Lastly, could this issue be the reason some of my radiators are not fully heating up?

ethicalpaul

You can raise all kinds of things, but if the near-boiler piping is putting boiler water into your main, it will all be for naught.

I'm trying to think of the best way to determine if the water is getting thrown up into the main and then making its way to your vents, or if the water is getting pushed by pressure back up your returns.

I think a low-pressure gauge could tell you. If the pressure is getting high, then the water is probably getting pushed up the returns.

Or if the pressure is rather steadily low and the water appears shortly after steam starts, then that points to the water getting carried over by the incorrect boiler piping.

pnm2

@ethicalpaul Could lowering the maximum PSI on the pressuretrol and seeing if that has (or does not have) an effect help me determine the source of the water?

ethicalpaul

Yes, if the pressuretrol is accurate it will keep your system pressure under the indicated level...unfortunately this isn't always the case. They are often "late" to cut-out the boiler.

A low-pressure gauge will help you verify.

ethicalpaul

The more I think about it, if your main vents were off, that basically removes high pressure as a cause since pressure would be unable to build with the vents off.

So I am fully behind the theory that your incorrect near-boiler piping is causing water carryover into your main.

Here's what it looks like: https://www.youtube.com/watch?v=jvt8qxBaRJU (this video had dirty/oily water causing the carryover but the idea is the same)

pnm2

@ethicalpaul Doesn’t the fact that it takes a considerable amount of time (in one case up to 7 minutes) for water to begin spurting out of the vent opening indicate that it’s coming from the return and not the boiler? If so would that suggest the likely culprit is the low height of the return?

ethicalpaul

7 minutes from when? from when the call for heat started, or from when the steam started being produced in earnest?

But the real answer is "no" with the main vents off, your system can't build any pressure so I believe we can rule out water getting pushed backwards up the returns. There's nothing to push it.

I sense a resistance to accepting that your near-boiler piping is problematic. It's like that guy who lost his keys in the living room but is looking for them in the kitchen "because the light's better"

pnm2

@ethicalpaul Haha you're not wrong.

pnm2

@ethicalpaul It was 7 minutes from when the call for heat started. I didn't witness any steam at all from that vent opening until I shut off the burner and water stopped spurting out. But it sounds like it doesn't matter anyway.

ethicalpaul

Yeah. Most or all of that 7 minutes was probably just getting the water up to steaming.

If you really really don't want to touch the piping, and don't want to try to get the installer to fix it, then you can probably get things in order anyway.

They key is to have very clean water, make sure your water level isn't too high (even try lowering it a bit even if just for experiment), and make sure your boiler isn't overfired. You want the main venting to be ship-shape, which I know you are doing (and is why we even know that water is in your mains)

Here is my own system a couple years ago when I started messing around with it. I put a sight glass on my return and was surprised to find water there, just like you. Check it out: https://forum.heatinghelp.com/discussion/168004/sight-glass-on-main-shows-a-surprise