One pipe steam boiler pressure too high

sobriquet

Hello, I’m having an issue this year I wanted some opinions on. Single pipe residential steam. I recently installed a low pressure gauge (0-3psi). During that installation, I removed and cleaned the pigtail, and verified the pressuretrol settings - 0.5 cut-in with differential wheel at 1. This is how it has been set for 10+ years. I’m now having an issue with radiator vents leaking like crazy. Low pressure gauge is indicating the boiler is shutting off a little above 3psi. I never had a low pressure gauge before, so I can’t attest to the accuracy of the pressuretrol in years past, but I’ve never had vents leaking like this. I could even hear spitting/hissing at one of my main vents. Yes, I have adequate main venting. 5 Gorton number 2s in total.
One other thing that may be contributing to abnormal conditions this year. Two radiators are currently removed and supply pipes plugged due to minor house renovation work. I understand this may cause an oversized boiler condition, but I assume my pressures should still not exceed my pressuretrol settings.
Does all this indicate a defective pressuretrol?

Did I cause this problem after removing/installing the pigtail and pressuretrol?

If my pressure controller is indeed the culprit, should I spring for a vapor stat?

Any thoughts or insights would be helpful,

Thank you

EDIT: one more thing, this high pressure seems to only occur after a setback, when attempting to raise home temp from about 65 to 70 in the mornings. When the system is simply maintaining temperature, my low pressure gauge indicates no pressure whatsoever.

Long Beach Ed

It has been a cold winter for many of us. When you recover from a setback, only then are the radiators completely filled with steam and the vents will close, or they are supposed to close. So any vent that doesn't close properly will exhibit problems as yours are.

Either your vents are in poor condition or of poor quality, or your pressure is too high, your piping is incorrect producing poor quality steam or of too high velocity.

Temperature setbacks often don't work well with steam systems, and often wind up costing you money.

If you post some photos of the piping around your boiler I'm sure some folks here can offer suggestions.

sobriquet

https://forum.heatinghelp.com/discussion/comment/1844319#Comment_1844319

I will try to get some photos. Based on my very basic knowledge of steam, my near boiler piping appears to be far from perfect. Is it recommended to not set the thermostat down? Just maintain a steady temp day and night? Is it more cost effective?

Long Beach Ed

https://forum.heatinghelp.com/discussion/comment/1844320#Comment_1844320

It depends… It very well may be a cost saving. It would depend on boiler and radiator sizing, heat loss and piping. Probably best to experiment.

109A_5

Your pressuretrol may have never worked correctly, they seem to have a history of being dysfunctional. My lungs can trip mine when set to 1.5 PSI cut out. Also the switch should be verified that it actually opens the circuit when you hear the click.

With the radiators removed it may have been just enough EDR reduction that when recovering from a setback the pressure rises enough to make a dysfunctional pressuretrol more obvious.

ethicalpaul

3 psi is all too typical for a pressuretrol even at the lowest settings.

I don't like my system to be anywhere near that pressure, so given the meager selection of solutions out there, I would recommend a vaporstat rather than running at 3psi. Anything better or cheaper would require substantial DIY skill and mentality.

How big is this system with 5 Gorton #2 on it?

I think you are just noticing more or as others said the weather or setback is different. There's nothing about adding a gauge that would make your boiler be higher pressure causing leaking vents.

techforlife

Is your pressuretrol an old mercury tube job that is not level?? Replace pressuretrol with a Vaporstat, a much better control.

sobriquet

https://forum.heatinghelp.com/discussion/comment/1844509#Comment_1844509

ive been interested in upgrading to a vapor stat for years, just haven’t gotten around to it. It’s a 3 story house, about 2500 sq ft I think. There are three mains coming off the boiler, 2 are about 40 feet, 1 is closer to 20. The suggestion of 2 gorton number 2s for each 40 foot run came from this forum, years ago. Then I put one on the shorter run. When I bought the house (2013) there were no main vents at all. What a difference that made. I think I am noticing things more this year as well, with how cold it’s been in NJ.

sobriquet

https://forum.heatinghelp.com/discussion/comment/1844601#Comment_1844601

I’m not sure. I assume it came with the boiler when installed (97). Did they still use mercury then?

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1845362#Comment_1845362

Thanks. yeah this forum overstates venting sometimes 😅

danmayer175

I get similar issues when there's too much pressure in my system. Anything over 2 psi reveals leaks that never leak at low pressure. I calibrated the pressuretrol to keep things under 1.5 and haven't had any issues since.

ethicalpaul

low pressure covers many sins

Long Beach Ed

Main vent sizing is dictated by the amount of air in the main and the steaming rate of your boiler. A boiler that takes ten minutes to produce steam for a main doesn't need that main vented in two minutes. A 40-foot 2" main can usually quite effectively be vented with one or two Gorton #1 vents.

A properly sized boiler will only turn off on pressure on the coldest "design day" days, hardly justifying the added expense of a Vaporstat. Here in New York that's perhaps once or twice a year.

Unless the entire system is evaluated, and each repair assessed and prioritized, throwing parts at it often wastes money that could be better spent correcting the worst deficiencies. Amateur assessments often default to the easy stuff and miss the true problems.

ethicalpaul

Well said, @Long Beach Ed

An interesting test in this case would be to interrupt a call for heat (to ensure the main is hot—this gives the "worst case" in terms of the shortest amount of time that a boiler could heat a main).

Then remove one of the #2 vents on one of your mains. Leave the fitting open.

Then let the boiler turn on again after a few minutes (to ensure air is back in the main), and time how long it takes for steam to get to the open fitting. This is how long it takes to vent with an open pipe (obviously).

Then turn off the boiler, plug the open fitting, and do it again with timer. You'll have to watch the remaining vent to see when it stops venting air—that's how long it took for a single #2 to vent that main.

Compare the times. If they are close, then put the extra #2 on the shelf and save it for when the first one fails. It's better to have a single correctly-sized vent than two of them—it takes steam and time to close the second one, and there is twice the chance for failure.

Then repeat for your other main with two #2s on it.

Let us know the times! This is how we learn what to tell people in the future, thanks!