Steam from some vents seems excessive this year

gabesteamheat

Greetings. My home has gas powered single pipe steam radiators, we’ve been here for about a decade. Two years ago, I replaced most of the vent valves on the radiators. While we are accustomed to the vents letting off some steam, it seems excessive this year with some going off pretty much whenever the radiators are hot, so much that at least one is soaking the wall as its blowing quite forcefully.

I've ordered a few new valves set to arrive next week. In the meantime, I'm soliciting advice on what adjustments to make to the existing valves around the house as they can be opened & closed to varying degrees. Some tidbits which may or may not be relevant:

1. We have, and have had for several years, the attic radiator shut-off completely has its entirely too big for the space & sweltering up there (now a home office since COVID)

2. The basement was too hot as well, so I put insulation on about half of the pipes down there to get to reasonable temperature, it’s been this way for several years.

3. We boxed in the boiler room last summer, which means the area immediately around the boiler is now hotter than they used to be

4. The busiest vent is an extension at the end of the main in the basement ie. it’s the last one on the line. Underneath this radiator/vent is a storage area which has insulated pipes & is now closed off from rest of basement with a door ie. the room is colder than the rest of the basement b/c the pipes are insulated.

5. Pressure is SET to 2 psi, however last night before bed, as temp. was dropping sharply, I noted the meter read 4 psi despite the 2 psi setting. This morning it went back down on its own to 2 psi. I will continue to monitor but that’s all I can say about it now.

6. Including basement & attic, its 4 levels w/ bedrooms on 2nd level so a lot is going on vertically. To our knowledge the house has hollow walls w/ no insulation.

ethicalpaul

Is it possible that your pigtail below the pressuretrol is clogged? When I hear about a vent "blowing quite forcefully" I automatically think "well that pressure is too high"

EdTheHeaterMan

The 4 PSI high limit on your system is more than you need. It appear that the Empire State Building is steam heated with less pressure than that. So your 4 story building can get away with less than 2 PSI.

There are two things that come to mind.
1. What pressure control do you have and what pressure is it set to?
2. There should be a pigtail fitting. It is a piece of 1/4" pipe (or 3/8" Pipe) that is bent in a circle to create a water seal to protect the control for touching raw steam that be too hot for the measuring part of the control. When was the last time someone took that apart and blew air thru it. If that is plugged, then the pressure that is getting to the control may not be the pressure that is actually in the boiler

There are other possibilities, but I would check those two first.

EBEBRATT-Ed

I agree with @ethicalpaul

If no one adjusted you pressure control and the gage reads higher than the pressure control setting (the scale on pressure controls can be inaccurate) then you could have a plugged pigtail, or the gauge could be bad or someone adjusted the pressure control.

Those would be the first things to check.

gabesteamheat

Pressure is set to 2 psi, but was reading at 4 psi last night. This morning is was back to 2 psi. I'm not sure of the control, I will check out when I get home.

Pigtail may have not been blown out since we've lived here. We've had a technician come out a couple of times over the years, but I don't recall this ever being done. That sounds like a good starting place, thank you.

Jamie Hall

Start by cleaning the pigtail and resetting the pressure control to 0.6 psi cutin and 1.6 psi cutout. That's ample.

EdTheHeaterMan

Jamie Hall said:

Start by cleaning the pigtail and resetting the pressure control to 0.6 psi cutin and 1.6 psi cutout. That's ample.

Agree here. But depending on what control you have, the differential setting may be additive or subtractive. That can be confusing to some folks. Knowing the model number of your control will be helpful

neilc

Gabe,
can you post some pictures around your boiler,
of your Ptrol, maybe the sightglass, Low Water Cutoff?
which you blow down occasionally, right?
pictures make it easier for us to help you, especially about setting the Ptrol

gabesteamheat

Here are a few pictures.  I'm probably setting myself up on a platter here, but aside from tinkering with the valve settings on the radiator I've done next to nothing.  So it seems I need to (1) clean pigtail (2) perform blowdown 

gabesteamheat

gabesteamheat

gabesteamheat

Jamie Hall

OK. Easy step 1. That type of pressuretrol is called "additive" and the scale on the outside -- which you can see -- is the cutin pressure. There is a handy screw at the top. Turn that screw until the slider on the scale is just above the lowest marking -- 0.5. Inside there is a wheel which determines the amount of additional pressure needed to turn the boiler off. It is most likely set a 1, which is where you want it -- don't mess with it at the moment if you don't want to. I don't see an easy way to get at that pigtail to clean it, but it looks as though the pressure gauge is also mounted to it, so if it is going up and down as the boiler fires and quits, don't worry about that yet either.

neilc

ok,
you have a lot of room to dial that Ptrol down, it looks to be about 2, that's your cut in, (when the boiler turns back on),
right now I'm guessing you're operating between 2, and 3/4 PSI, too high.

You can turn that indicator down to its bottom, just stop turning as soon as you start to feel resistance, if you go too low, and the boiler does not refire, just raise the indicator up by 1 turn,
Inside, under the cover, is a small white or grey wheel with 1 - 5 on it, this is your differential, and is added to your cut in to give you a cut out, set that to 1,
Your boiler should turn on at ~0.5 PSI, and turn off at ~1.5, that's ideal,
definately aim for less than 2 for a high,

EdTheHeaterMan

That pressure control is additive. And it is set too high. You want to set the cut in as close to 0.5 as you can get without the innerds disconnecting. (innerds is a technical term) like maybe 0.7ish.
On the inside there is a white differential dial. Set that to 1. that will make the high limit around 1.7 top 2.0 (That control is not very accurate).
The Brass pipe that is bent into a circle is the pigtail that should be removed and checked to see that you can blow through it. Don't do that when there is steam in the boiler, (it's like McDonalds Coffee) you will burn your lips

So here is what may have happened. The burner lights and makes steam and the boiler pressure goes up to 5 or 6 PSI (or even higher). The pigtail is clogged and the boiler pressure takes time to work its way through the blockage and make the burner stop at the gauge pressure of 2.3 or something like that. But the boiler still has the higher pressure in it for some time, then the pressure in the pigtail keeps going up. Eventually the boiler pressure drops to some regular pressure like .5 PSI or even 0, but the blocked pigtail is still clogged and does not let the 4 PSI pressure out very fast. So when you looked at the gauge, it read 4 PSI but the boiler may have been off for sometime and the real pressure may be back down by then OR you looked at it when the boiler pressure was still over 5 PSI but the clogged pigtail was not showing you the proper pressure. (See how this can be a problem). Now after the thermostat is satisfied, everything goes back to normal the next day.

Another possibility is that the gauge is defective. There may be no pressure in the boiler and the gauge is pointing at 2 PSI. That means that when the needle points to 4 PSI, it really is indicating 2 PSI. You need to know that the gauges and controls on these boilers are El Cheapo designed to meet the MINIMUM code requirements. If you want accurate control and gauges, you need to add (Not Replace) the more accurate expensive controls and parts to get accurate control.

neilc

LWCO,
Your's (how do you spell your's) is probe type, so you don't have the weekly chore of blowing down a float chamber.
You should still take some water from the boiler drain once a month or so, read your manual, This takes some dirty, muddy water out of the bottom, and is good to do. Keeps the muddies and dirties away from the probe.

Sightglass,
is a little dirty water in there,
See to the right, where there's that small hole in the boiler jacket?
and the exposed fiberglass insulation, that's where you shold have a skim port.
Your installer, didn't, and there fore, didn't finish their job, skimming the boioler a time or 3,
That plug under the fiberglass should be removed, and a nipple and cap installed,
so the boler can be skimmed.
Back to that dirty water, see the moisture above the water line, and it almost looks oiley, this needs to be skimmed.
It's in your manual, or in plenty of threads here,

Book for you,
https://www.heatinghelp.com/store/detail/we-got-steam-heat-a-homeowners-guide-to-peaceful-coexistence

https://www.heatinghelp.com/store/

EdTheHeaterMan

Jamie Hall said:

OK. Easy step 1. That type of pressuretrol is called "additive" and the scale on the outside -- which you can see -- is the cutin pressure. There is a handy screw at the top. Turn that screw until the slider on the scale is just above the lowest marking -- 0.5. Inside there is a wheel which determines the amount of additional pressure needed to turn the boiler off. It is most likely set a 1, which is where you want it -- don't mess with it at the moment if you don't want to. I don't see an easy way to get at that pigtail to clean it, but it looks as though the pressure gauge is also mounted to it, so if it is going up and down as the boiler fires and quits, don't worry about that yet either.

Easy way to check the pigtail is to remove the gauge and take a 1/4" Barb x MPT fitting with a piece of 1/4" vinyl tubing attached and BLOW. If there is a blockage, you can tell

RTW

Not sure this applies directly to the problem, but on the issue of the Pigtail, I just had that checked out and it was clean. However, the Tech wanted to fill the Pigtail with water first before re-installing saying the water played a positive role in conjunction with the Honeywell Pressuretrol it is directly connected to( same one pictured in this post) The gauge is teed off

dabrakeman

Yes, the pigtail should have some water in it to form the trap.

If you are regularly seeing even 2psi (regardless of the ptrol setting) in your system then eventually you are going to be failing vents. I doubt you are seeing mid winter extreme temperatures yet so the real question in my mind is why are you building any significant pressure at all. Are you doing large recoveries from setbacks? Do you have good main venting? Is you boiler way oversized? Please do as the others have said and reset your ptrol to lowest settings which will ease the strain on your radiator vents, but I expect you may then start cycling on pressure more often which begs answers to some of the other questions I have posed.

mattmia2

The gauge is very likely not very accurate at low pressures, you need to tee in a 0-3 or 0-5 psi gauge to know what pressures you're really seeing.

ethicalpaul

The good thing about pigtails is they fill themselves up with distilled water if you leave them dry.

RTW

The good thing about pigtails is they fill themselves up with distilled water if you leave them dry.


In response, do I not need to check if water is in Pigtail after it has been installed with water? I have the tech. person return mid-winter to only change out the oil filter that feeds the boiler ( thus, filter replace 2x a year) Im sure its doable but wanted to check to be sure Regards, Bob

RTW

Lastly, while Im thinking of it, the Pigtail in my system is below the Pressuretrol only, Not the gauge that is teed off. Is that OK ? My steamheating system is fine and I find boiling the vents in white vinegar every few years good practice as preventative maintenance. Gorton's on Main Vents and MOM on radiators seem to work

dabrakeman

Looks to me like your gage is above the pigtail trap and OK.

ethicalpaul

RTW said:

The good thing about pigtails is they fill themselves up with distilled water if you leave them dry.


In response, do I not need to check if water is in Pigtail after it has been installed with water? I have the tech. person return mid-winter to only change out the oil filter that feeds the boiler ( thus, filter replace 2x a year) Im sure its doable but wanted to check to be sure Regards, Bob

No, you don't have to check the pigtail for water. You just have to check it every couple years to ensure it is not blocked with mud/rust/gunk

gabesteamheat

Update: I have incrementally been lowering the Pressuretrol w/o much impact, pressure still approaches 5 psi at times. I scheduled pros for boiler maintenance but they are booked for the next month so I am bringing in the (probably overpriced) guy for troubleshooting this Friday.

My latest observation is the main valve never seems to be offing steam. While all the radiator vents are busy, the one that is out of control is the last one on the line - the one on an extension just after the main vent. Is it a plausible theory that the main vent is busted, with the last radiator on the line taking the brunt of the pressure?

gabesteamheat

Here's a pic of main vent that has been quiet despite the radiator vents going crazy.

Jamie Hall

If I didn't say it already, get that pressure down. Not sure what the problem is -- clogged pigtail, mss set pressuretrol, or what -- but get it down.

To 2 psi or less.

A once or twice spike above 3 psi isn't going to damage a vent -- usually -- but routinely running up there and that vent is toast. Shame about that #1 which is quiet, but you've learned an expensive lesson.

ethicalpaul

To add to the correct stuff that Jamie said, no vent should be "offing steam"

mattmia2

Did you add a low pressure gauge or are you basing the system getting to 5 psi off of the 0-30 psi gauge?

gabesteamheat

mattmia2 I'm basing it off the 0-30 psi gauge

mattmia2

gabesteamheat said:

mattmia2 I'm basing it off the 0-30 psi gauge

Tee in a 0-3 or 0-5 psi gauge or gauge calibrated in ounces, those 30 psi gauges aren't accurate at low pressures, especially if they have been bashed at some point during other work. You may be looking at the wrong problem.

gfrbrookline

A low pressure gauge is a great addition, 0-30 is required but worthless, but the poster stated s/he is lowering the setting incrementally. If the ptrol is just set to .5 and 1 it will likely resolve the vents from hissing if that is the problem.

The question that hasn't been asked is when the vents were replaced what were they replaced with? A change in brand or venting rate can make a huge difference. Were they replaced like to like or with a different vent? If the new vents are not good quality they may have failed and no longer close so they allow steam to openly vent out not related to the ptrol setting. If the previous vents didn't leak steam with the ptrol set at the same setting it is likely the vents that are the problem. The ptrol may be out of calibration which is not uncommon.