Gurgling/boiling water sound from one radiator

cmNJ

Two-story 1925 colonial in northern NJ, one pipe steam system. Having an issue with one of my upstairs radiators. I get a loud gurgling/boiling water noise usually about 7-8 minutes after the boiler fires (after the radiator gets hot), lasts for about 10-15 seconds, and occasionally repeats 1-2 times depending on how long the boiler is firing. It doesn't sound like it's coming from the radiator itself but in the supply pipe just below the valve.

It's my primary bedroom and loud enough to wake me up so I've been trying to pinpoint the issue. Last winter, I had a plumber come out to balance the whole system. He checked and fixed the pitch on all the radiators and replaced some old vents with new Gorton 6's. But, he couldn't figure out the gurgling noise so he suggested turning the radiator vent upside down as a stopgap.

Weird thing is, it actually worked. With the vent upside down, the gurgling/boiling water sound disappeared entirely. Radiator of course takes longer to heat up, but it's a comfortable sleeping temperature so we don't really mind.

For context: this radiator is the first one off the main and is almost directly above the boiler.

I have two questions:
1) Is it possible this issue is caused by a poorly pitched supply pipe? I have really crooked floors on the 2nd floor that may have ruined the pitch of the horizontal pipe connecting the radiator to the vertical riser, allowing water to settle there. Does that theory make sense? If not, is there something else I may be missing?

2) Is an upside-down radiator vent a viable long-term solution? Could this lead to other problems long-term or somewhere else in the system?

I've read Dan's book and have tried to learn as much as I can about how my system works, but I'm still very much an amateur so I appreciate any and all advice/opinions from the experts here.

Hap_Hazzard

Turning the vent upside down causes the float to close the vent, effectively turning the radiator off. If it's getting hot anyway, you have a leaky vent. It may or may not be closing when it gets hot, as the bimetal strip presses the float against to port with more force than the weight of the float alone, but it's still a leaky vent. Turning the vent upside down is usually a temporary solution, but if you're happy with the result, you might as well leave it. Unless there's water spitting out of it, it's not hurting anything, and it might be tough to duplicate the behavior with a good vent.

EBEBRATT-Ed

Yes a poorly pitched pipe could cause this. You might try using a crowbar or 2x4 and some blocks as a lever raise the radiator 1/2" (carefully) keep the radiator pitched toward the valve and put shims under the feet. See if that helps.

A different air vent that vents a little slower may help. You could try that first. Also make sure the boiler pressure does not exceed 2psi. The lower the pressure you run the better the vents work and the less problems you have. Ideally the boiler gauge should show no pressure

ethicalpaul

See my saga with this issue, it may give you some ideas: https://forum.heatinghelp.com/discussion/167233/fixing-pitch-issues-in-old-house

cmNJ

Hap_Hazzard said:

Turning the vent upside down causes the float to close the vent, effectively turning the radiator off. If it's getting hot anyway, you have a leaky vent. It may or may not be closing when it gets hot, as the bimetal strip presses the float against to port with more force than the weight of the float alone, but it's still a leaky vent. Turning the vent upside down is usually a temporary solution, but if you're happy with the result, you might as well leave it. Unless there's water spitting out of it, it's not hurting anything, and it might be tough to duplicate the behavior with a good vent.

I did try replacing the upside-down Gorton 6 with a (right side up) Gorton 4, but the gurgling still happened. So, now I turned the Gorton 4 upside down and it's right back to where it was. So, maybe I have two leaky Gorton vents? Or, maybe it's not a tight seal? Either way, it's good to know that it doesn't necessarily hurt anything to have the vent upside down. Appreciate your insights @Hap_Hazzard.

cmNJ

EBEBRATT-Ed said:

Yes a poorly pitched pipe could cause this. You might try using a crowbar or 2x4 and some blocks as a lever raise the radiator 1/2" (carefully) keep the radiator pitched toward the valve and put shims under the feet. See if that helps.

A different air vent that vents a little slower may help. You could try that first. Also make sure the boiler pressure does not exceed 2psi. The lower the pressure you run the better the vents work and the less problems you have. Ideally the boiler gauge should show no pressure

Thanks @EBEBRATT-Ed. Thing is, that radiator is already pitched about 3/4" due to my wonky floors (plumber needed three washers and a nut on both back legs to get the pitch right). So, I don't think I can pitch it any higher. That's why I'm thinking it may be in the pipes rather than the radiator.

I did try a Gorton 4 with no luck. I also set my pressuretrol to cut out at around 1psi. I don't have a low-pressure gauge so I can't confirm 100%, but I was at the boiler yesterday and saw it cut off just below 1psi so I'm pretty sure it's not a pressure issue.

JohnNY

Bad boiler piping can and does cause this too.

cmNJ

ethicalpaul said:

See my saga with this issue, it may give you some ideas: https://forum.heatinghelp.com/discussion/167233/fixing-pitch-issues-in-old-house

Impressive work @ethicalpaul! Since the wife is comfy now I doubt she'd sanction such a big re-do on our end (especially with my still-developing DIY skills) but your story was fun to follow. The issue you described sounds identical to mine so it does make me more confident that the problem is with the horizontal run. So, now just a matter of if/whether to try and fix it...

JimSavy

I had the same problem, have a whole discussion about it. I’m learning as well. The vents were eventually replaced with varivalves, which were quieter but still gurgled. Problem is now one of the pipes is banging and clanking and I’ve yet to find a solution to it.