New Steam boiler; higher pressure on pressuretrol

jimmyenz17

Hi everyone,
I am new to the site, learned a lot while searching the content but was wondering if someone can help me with my situation.

I did an Oil to Gas conversion 4 months ago (from 500,000 BTU Weil McClain to 450,000 BTU W-M EGH 105). It's a 3 story, 5000 sqft home with 11 radiators; one-pipe system (I had 2 plumbers giving me same BTU based on EDR calculation my radiators.

After a few months of having the new system (and noticing my heating bills being higher than when I was using Oil, although it is hard to compare in therms since it was in oil), I noticed my pressuretrol is reading high and it usually shuts off the heating cycle at 6 PSI. I thought maybe my system is short-cycling.

Other things I have noticed are:
1. Water level at the glass water gauge fluctuate a lot; sometimes to the point that it would stop the heating cycle because low-water cut off gets activated (light turned on). Then after a few minutes (when water could come back to the boiler), boiler would turn back on. In the past I had some leaks in the radiators which I fixed.
2. The Pressure rises from 0 to about 5 PSI in about 8-9 minutes of heating cycle from when I call for heat (eg thermostat set at 69 when room temperature was 67). The heat cycle would terminate before target temp was reached, i assume due to cut-out pressure setting. Then after couple of minutes when PSI would come down to 4, the boiler would turn on again.
3. A few of the radiators are a lot louder (couple on the 3rd floor especially), a lot more banging, after switching from the old oil steam boiler (WM, 500K BTU) to newer Gas Steam boiler (WM EGH 105, 450K BTU).
4. I think near-boiler piping appears to be subpar based on what I researched from this website and also from Dan's informative youtube videos (mainly height of header is too low).
5. Main Venting was also insufficient.


So I asked the licensed plumber who installed the system to come back to address some of these issues and his answer was it's great that the system is able to run well at higher pressure??!?! I told him for residential system it should be really less than 2 PSI. Anyway, what he did was:
1. He did x1 skimming (to address water level fluctuation).
2. I asked him to replace the small vents on the Main and instead put in Hoffman 75 vents (this helped heating the house faster). He did that.
4. I asked him to raise the Header height to at least 24 inches (currently its 17 inch off the top of boiler; interestingly on boiler's instructions it says at least 24" from the water level, I know Dan says it should be minimum 24 from top of the boiler to under the Header). He said let's see what Skimming does first and maybe he considers raising the height....


My question is this, aside from possibility that the boiler may be oversized (even though 2 independent plumbers calculated EDR and came to same 450K BTU requirement), what are other possible causes for high pressure on my pressuretrol? I doubt it's Gonk in the pigtail (although I will ask him to check that when he comes back).
More specifically,

*) Can low height of header (17 inch") cause high pressure due to Wet steam? If so, would it work if I increase the height of riser using Dropped header (i have limited ceiling height and not sure how much I can raise the heigh of the actual Header).
**) I assume I have significant "wet steam" given low header height. If so, I have 2 steam pipes feeding my entire house, one of them is smaller in diameter than the other one (almost half the diameter of the Header). I remember Dan was talking about bernoulli effect causing Wet steam to shoot up faster in smaller diameter pipe. Do I need to ask for that pipe to upsized? Would that help with the pressure.

I really appreciate the help. Please find the pictures attached.

109A_5

Hello @jimmyenz17,
It may need more skimming.
The Pressuretrol probably should be set to the minimums.
Cut-In = 0.5 and the Differential (inside cover) = 1, you did not take a picture of its current state.
If it is set correctly you need to find out why the pressure appears so high.
The Presuretrol does not force the Boiler to 5 PSI it is a safety limiting device, limiting the pressure by shutting off the burner.



If the near Boiler piping is not per the manual or better it probably should be changed.
https://www.weil-mclain.com/sites/default/files/field-file/EGH Boiler Manual.pdf

EBEBRATT-Ed

The header looks too small. Check the size with the chart @109A_5 posted above. The boiler needs skimming.

The higher the header the better but 24" from the water line should be ok. If the header is too small have him raise it as well. You want the pressure control should cut the burner off at 1 1/2-2 psi and back on as close to 0 as you can get it.

If you boiler is building pressure that quickly your either way short of venting or the boiler is way oversized which is what i would suspect. They either didn't calculate the edr right or didn't do it at all.

at least they used black pipe and not copper

jimmyenz17

The size of the header is 3 inch (matches the manual recs). This is the picture of vents. Is that enough? Would more venting help with pressure issues? 

109A_5

Hello @jimmyenz17,
The calibration of the Pressuretrol may be suspect too. They are known to be not accurate.

Also the Boiler specifications that you stated don't seem to match the manual.
"newer Gas Steam boiler (WM EGH 105, 450K BTU)"
Regardless I think it would be a good idea for you to do your own EDR survey so you know better where you stand. Do you have the EDR numbers from the contractors ?

Mad Dog_2

Good 🌄 Morning pal.  Sorry you are having trouble. You are on the right track, but instead of guessing,  it would behoove you and save you alot of precious time & $ to 
Have one of us Heating.Pros  pay you a Field Visit.  Where us the boiler?    Here to help.  Mad Dog   🐕 

KC_Jones

If you’re getting to 5 psi in 8-9 minutes the boiler is oversized or the venting is inadequate, I’m betting both.  EG-105 for 11 radiators would mean each radiator is the size of a truck, like 3’ tall and 4.5’ long.

I guess anything is possible, but the performance you are seeing indicates oversized to me.  Remember the pressurtrol is a safety device and under normal operation it shouldn’t do anything as you shouldn’t be building a meaningful amount of pressure. 

If you measure the height from floor and depth of each radiator and post a picture of the end of each to see the design/style we can help you calculate the EDR to check.  The calculations are easy.

dabrakeman

I'm not the expert here but if those mains are setup as counterflow which it looks from the picture like they are shouldn't the condensate be dripped off directly to the Harford loop rather than into the header?

I have a 4500sqft home with 11 good size radiators and am 30% oversized with an EG65... Sizing might be the biggest problem here.

jimmyenz17

Thanks for your comments everyone, you guys are amazing.
@109A_5 and @EBEBRATT-Ed you are correct; my model is actually EGH 115. And the header size then is small, it should be 4 inch as you mentioned, I can not believe this. How could you even tell from the image!!

@KC_Jones and @dabrakeman , Also please find a picture of my radiator sizes (columns etc), I still can't figure out how to calculate EDR. I re counted my radiators and I have total of 17 radiators actually (there used to be 19 radiators, 2 of the smaller ones were removed as I created a zone with different heating source).

At this point, I spent so much money on getting this steam boiler installed, what are my options to deal with an oversized boiler? I can not afford a new installation again unfortunately. Would increasing diameter from 3 to 4 inch, raising height of header help with pressure issues, or am I just wasting time if the boiler is way oversized?

@Mad Dog_2 I went with a really reputable local guy, I wish I knew about this website beforehand. I will look to see if I can find someone for consult on how to adjust the existing system since the installing plumber does not seem to know enough about steam. I'm in northern NJ area

WMno57

jimmyenz17 said:

I can not believe this. How could you even tell from the image!!

Because of the 2 1/2" to 2" reducing elbows that transition from the dual vertical 2 1/2" risers to the 2' header. Your "master plumber" likely did this because he does not own a pipe threader capable of threading pipe larger than 2". 1" to 2" pipe is threaded at 11 1/2 threads per inch. 2 1/2' and larger pipe is threaded at 8 threads per inch. A different and much more expensive tool. He probably bought pre threaded 2 1/2' inch nipples for the risers.

KC_Jones

If you could post pictures of the different style radiators you have that would be useful. It's not just the size it's the style that impacts the radiator EDR.

EzzyT

@jimmyenz17 I’m located in northern NJ give me a call at 2018878856. I could come out and take a look at your system.

jimmyenz17

@KC_Jones these are some of the radiators. 4 of the radiators are recessed. 2-3 of the radiators are small, single column. The rest are larger size as in image I attached. 

@EzzyT, thank you, I will get in touch soon. 

ethicalpaul

jimmyenz17 said:

The size of the header is 3 inch (matches the manual recs).

How are you determining the header is 3"? By measuring? Or looking at the number stamped on the fittings? I can't read any of them in the photos but it doesn't look like 3". It almost looks like the header and steam supplies are 2" and the smaller riser is 1-1/2" but photos can be deceiving.

KC_Jones

ethicalpaul said:

jimmyenz17 said:

The size of the header is 3 inch (matches the manual recs).

How are you determining the header is 3"? By measuring? Or looking at the number stamped on the fittings? I can't read any of them in the photos but it doesn't look like 3". It almost looks like the header and steam supplies are 2" and the smaller riser is 1-1/2" but photos can be deceiving.

For the OP.

2 1/2" pipe will measure 2 7/8" OD, 3" pipe will measure 3 1/2" OD

I ran the numbers you supplied and made a few assumptions because at this point it's a reality check. Here is a screenshot of what I got. I'm getting 673 and you have a boiler rated for 977. See the second screenshot for what that means. Also I assumed you have the EGH-105, but as was pointed out earlier that unit is rated for 405,000 input, but you stated 450,000 input so there is a typo somewhere. So based on those numbers the boiler is 45% oversized or has a pick up factor of 93%. I would rate that as grossly oversized. For me, I'd be threatening legal action if they didn't put the proper size in on their dime. At this point they have been paid to screw up your house, and what they did might not even be piped correctly if that isn't 3" pipe. With that system EDR you didn't even need a commercial boiler, the residential line should have been fine. You could have gotten away with an EG-65, but most likely an EG-75 is what a contractor that knows what they are doing would have put in.

jimmyenz17

@KC_Jones thank you so so much for taking the time to calculate the EDR. I really appreciate it. This has been such a frustrating process, i didn't even post all the other crap that went wrong during that installation (eg he cut the wrong steam pipe as we were removing the radiator and steam filled the whole room when I turned on the system, luckily I was at the house to turn off the system, crazy stuff).

To learn the boiler is even more than 45% over-sized (the actual model is EGH 115, with 450K BTU) is unbelievable. He did not even follow basic minimum requirements of the actual manual (header diameter and height), wow. Thanks again for your help everyone.

KC_Jones

The EGH-115 is 61% oversized or 115% pickup factor.  It’s beyond grossly oversized.  Yeah that would have to be replaced on their dime IMHO.

These calculations aren’t even hard, sad that they can’t even do the most basic thing.

AdmiralYoda

@KC_Jones @jimmyenz17 It boggles my mind how often this stuff is screwed up!!! I'm a typical DIY homeowner and after about a day of reading on this website I feel more qualified than many of the "Pro's" out there!!!!

Not to put down anyone in the trade, but it seems like if you own a pipe wrench or something resembling a wrench you are qualified to work on steam. Like many industries (auto mechanic background here) it is the bad 5% that give the other 95% of people a bad name.

That boiler is large enough to heat a building over twice your size. Yikes!!!! You essentially have an engine out of an 18-wheeler in a mid-size sedan. No matter how much you baby it, you will never get good fuel economy.

dabrakeman

AdmiralYoda said:

@KC_Jones @jimmyenz17 It boggles my mind how often this stuff is screwed up!!! I'm a typical DIY homeowner and after about a day of reading on this website I feel more qualified than many of the "Pro's" out there!!!!

Not to put down anyone in the trade, but it seems like if you own a pipe wrench or something resembling a wrench you are qualified to work on steam. Like many industries (auto mechanic background here) it is the bad 5% that give the other 95% of people a bad name.

That boiler is large enough to heat a building over twice your size. Yikes!!!! You essentially have an engine out of an 18-wheeler in a mid-size sedan. No matter how much you baby it, you will never get good fuel economy.

Probably a majority of them are quite good at their trade but don't know anything about steam. Steam is not their trade. That might be 95% of the outfits in some areas.

ethicalpaul

The bad 5%? Sounds a little low regarding steam installs.

AdmiralYoda

@dabrakeman @ethicalpaul I am probably biased growing up in old homes with steam and now owning one from the 1880's, so it seems commonplace and relatively simple to me. But what concerns me is that the good outfits out there that are indeed skilled that just seem to hack steam systems/repairs together without caring or learning how to do it right.

My old man has a small auto repair business and I basically grew up in the shop. I can't tell you how many times something limped in due to a botched repair. We'd scratch our heads and think that it must have taken 5x the time and 5x the money to repair it so poorly!

That mentality has stuck with me I guess and I don't understand how if someone or some business is remotely talented in what they do....why can't they learn to do it right the first time rather than use the homeowner as a guinea pig is beyond me.

But it is like this in every trade, not just steam. .....rant deactivated.

clammy

I hope you had permits and written signed contracts on the conversion then you could possibly have a leg to stand on legally that and hopefully the plumber is willing to admit it and most likely replace the boiler all on his dime which I think in New Jersey would be a miracle . Possibly he ll try to lower the gas pressure or remove a bunch of burners but short of replacement there’s absolutely no miracles to be performed on a fairly over sized boiler . Even if the near boiler piping was over sized and perfect it would not decrease your short cycling . You may not be able to get him to admit he screwed up but you certainly are entitled to have it corrected or be reimbursed monetary from him but I think that might require the courts which may not be worth the time and return . You ll figure out his stand when he no longer answers or calls back at which point contract a lawyer . As other have stated replacing steam boilers isn’t for every one that has a pipe wrench in the tool box there’s simply a bit more required then just that and just having a plumbers or Hvac lic doesn’t mean you know squat the truth be told it allows you to do the work legally and pull permits bingo end of story
Peace and good luck clammy

ChrisJ

dabrakeman said:

AdmiralYoda said:

@KC_Jones @jimmyenz17 It boggles my mind how often this stuff is screwed up!!! I'm a typical DIY homeowner and after about a day of reading on this website I feel more qualified than many of the "Pro's" out there!!!!

Not to put down anyone in the trade, but it seems like if you own a pipe wrench or something resembling a wrench you are qualified to work on steam. Like many industries (auto mechanic background here) it is the bad 5% that give the other 95% of people a bad name.

That boiler is large enough to heat a building over twice your size. Yikes!!!! You essentially have an engine out of an 18-wheeler in a mid-size sedan. No matter how much you baby it, you will never get good fuel economy.

Probably a majority of them are quite good at their trade but don't know anything about steam. Steam is not their trade. That might be 95% of the outfits in some areas.

If they take the work and charge for it, does that not make it legally their trade by definition?

Accepting work you do not know how to do, and then working to figure it out and getting it done correctly is one thing. Accepting it, guessing, doing it completely wrong not even bothering to open the installation manual that comes with the equipment and then charging for it is another.


We see an awful lot of it on here. But maybe, there's actually hundreds of good jobs we never see and we only see the bad ones. I don't know.

clammy

I doubt there hundreds of correctly installed steam boilers being just about every one I see is hobbled in in some consorted way which generally is opposite of a simple diagram included in the i n o manual ,a picture can’t get much easier I do think, thought wrong . Which leads one to believe they are dyslexic either in there reading or in there interpretation of a drawing or are the one doing the spinning just that a pipe spinner connecting pipes cause that’s all it is correct . I vote on the second being I have got into arguments over the diagrams and we where both looking at it at the same time . The other reason is fear ,the fear that if done correctly it will cost far to much and they won’t get the job being there’s price will be higher then all the rest of the dyslexics he s bidding against . And let’s not factory in the internet and prices available to all, god forbid you make a mark up to cover your business expenses cost of living oh no
Most never see the value until they deal w nit wits w all types of excuses w no cures or answers aside from that s the way steam is and themselves are at there wits end and scream uncle and do one of three following things
1 they move plan on moving quite soon ( heard many many times to many )
2 attempt to live with it and usually referee to above
3 yank it all out and do hot air and ac being those guys have to know more then the last guy right
I really cannot remember 1 job in the last 10 years or more that was replaced that was piped correctly using the correct materials and following instructions not a one. As uncommon as one would think it’s as common as measles used to be .
Accepting a job without much of a clue on what to do or how to do it is commonly called flying blind and rolling the dice a lot of business follow this model and make tons of $ cause they didn’t roll snake eyes and got lucky it ,s called business and to stay in it you always need the $ that’s the #1 priority so you gotta sell sell sell what ever and figure it out as you go but keep the till full .
The cheapening of a price is soon forgotten after the bitterness of poor quality .
Peace and good luck clammy

PMJ

@jimmyenz17 ,

I think you said above that the previous boiler running on this system was even bigger than this one.

The question should be asked then - how did that one run? The main on the ceiling surely is big enough for that boiler. No, the header can't be that small - that much is sure, and choking off a boiler like that will surely cause pressure in the header before steam gets anywhere and cause high bills. But what was operation like with the old boiler? How big was its header? Was the old one running acceptably aside from the cost difference of the oil? They did downsize you from that one. How was it?

jimmyenz17

@clammy Thanks for your reply. Yea, I did have permits and signed contract. In fact, the town luckily failed the inspection on the boiler (they had no clue about near boiler piping or EDR etc, but failed on basic things such as lack of support on the wiring and gas line etc). This plumber did ghost me for a while, but to be honest at this point, with so many things being wrong, I do not want him to touch anything anymore.
In my opinion, there should be a separate certificate or governing body for Heating, HVAC and plumbing. Majority of home owners will have no clue about their mechanical room, let alone a niche steam boiler. They (including me when I was looking for a "plumber" last year) have no idea a licensed, reputable plumber does not = qualified heat specialist.

@PMJ , yea the previous boiler to my understanding was about 500,000 BTU (an old Oil, WeilMclain, I'll post the picture). I was meticulous on checking on it and the pressuretrol was never high (always less than 1 PSI) at the end of heating cycle. I did not take many pictures of near-boiler piping of the old system, there is one i found attached.

PMJ

I figured that was the case seeing the size of that main. Only 1 psi at the very end of the cycle. And if you don't want even that much pressure all that is needed is a different control method to end the burns a little earlier.

It seems then that quite a lot of extra boiler isn't necessarily the end of the world as is so often portrayed. The biggest problem here is the too small header.

Clearly the contractor's understanding of steam isn't what it should be. At the same time replacing what is already there with same in the absence of owner complaints to me isn't malpractice. I could run that boiler just fine with a big enough header. Obviously the delivery piping can handle it and fill radiators without pressure. That being the case I'd take the extra.

109A_5

jimmyenz17 said:

I was meticulous on checking on it and the pressuretrol was never high (always less than 1 PSI) at the end of heating cycle.

I still can't help but wonder if we are all on the same page here, since the context of the Pressuretrol description seems odd to me since the beginning of this post. The Pressuretrol is that gray box that you can change the settings on and is a pressure limiting device (by shutting off the burner). Not a device that gives you the reading of the Boiler's actual pressure.
Example;
"New Steam boiler; higher pressure on Pressuretrol" and
"meticulous on checking on it and the Pressuretrol was never high"
The Pressuretrol is not a pressure gauge. And still no close up picture of the current Pressuretrol settings (inside and out).

This is the Pressuretrol on your old Boiler:



The settings on the Pressuretrol don't change unless someone changes them and often they are too high from the factory. Was it replaced with the new Boiler ?

@PMJ, I believe your boiler is oversized in the classic sense and yet no pressure issues. And no flaky pressure devices to control operating pressures to deal with.

jimmyenz17

@109A_5 yea I mistakenly used pressuretrol and pressure gauge interchangeably. I never changed the pressuretrol setting (cut-in etc) in the old or new system. All I checked was the pressure reading on the pressure gauge (which I now know,  once it’s 1-30 psi range, low pressure readings may not be accurate anyway). 

PMJ

@109A_5,

I see what you are saying. But as I read it the OP has identified a clear pressure difference in his operation after the installation. Early in the cycle pressure vs late(and less). I am looking at a main big enough to deliver steam to his system from that boiler without pressure. The change is a header that is too small. I have a boiler the same size and a main that looks to be the same. The dead men clearly knew that extra size in the delivery piping made a lot of problems disappear. My setup is a good example - a big bull head T and no equalizer and yet no issues with wet steam or pressure or water level. Clearly not done "correctly" either, but no issues because of the size. There is just plain a lot of room for a lot of steam to move slowly.

My boiler actually is a pretty good match by the specs to my EDR at 1000. But at a 40 degree difference to the outside it runs 25% of the time. In design day conditions maybe 50% to heat the place so it clearly isn't undersize. When I moved in it did fill radiators every cycle and stopped on the vaporstat until I changed the control to end all that because it made no sense. I learned pretty quickly that any pressure ever was totally unnecessary. And it didn't take a boiler size change for me to do it...because the delivery piping was big enough.

I say if pressure doesn't develop until radiators are filling up then the boiler can be easily run without pressure with simple control changes. These systems don't ever need radiators to fill completely. I could be wrong but from what I am seeing and reading that is the case here. And, quite honestly as long as the fill can happen with no pressure I prefer to have the extra.

109A_5

jimmyenz17 said:

@109A_5 yea I mistakenly used pressuretrol and pressure gauge interchangeably. I never changed the pressuretrol setting (cut-in etc) in the old or new system. All I checked was the pressure reading on the pressure gauge (which I now know,  once it’s 1-30 psi range, low pressure readings may not be accurate anyway). 

OK now that we are past that, how is the new Preseuretrol set ? Is it the same or lower than the old Boiler ? Pictures may help.

PMJ said:

@109A_5,
I see what you are saying. But as I read it the OP has identified a clear pressure difference in his operation after the installation.

@PMJ, all I am saying, is @jimmyenz17's system probably has many installer related issues. Most of these issues may take time, effort, tools and money to straighten out. However, possibly if the Pressuretrol is set too high (still unknown in this post) it is easy to change with just a screwdriver and a few minutes time and may give some relief to the situation.

Since the Boiler is oversized many here would recommend a Vaporstat. For many reasons I believe your way of controlling a Boiler is superior than just going the Vaporstat route. Also a thermal switch and an appropriate timer may be in the same price ballpark or less than the cost of a Vaporstat.

For @jimmyenz17 to get the best economy and performance from the new system all the issues should be defined, addressed and resolved the best way possible. That said, I'm thinking the Boiler won't get changed, so your control method may be the best resolution for that.

jimmyenz17

@109A_5
I don't remember the pressuretrol setting for the old boiler, the image I attached before has poor resolution to tell the setting.
In the new boiler, the cut-in pressure is set as about 1.5 PSI or 2 (difficult to tell based on the marks) and the white dial that is inside the pressuretrol is set at 1 . So cut-out should be 2.5 to 3 PSI from what I understand.
I have been watching the heating cycle a few times and noticed that after 8-10 minutes the pressure on the gauge reads 6-7 PSI and at that point the boiler shuts itself down (I assume the gauge is just inaccurate and system is shutting itself at the actual cut-out I set on the pressuretrol). Not sure if I answered your question, my understanding is still basic!

KC_Jones

jimmyenz17 said:

@109A_5
I don't remember the pressuretrol setting for the old boiler, the image I attached before has poor resolution to tell the setting.
In the new boiler, the cut-in pressure is set as about 1.5 PSI or 2 (difficult to tell based on the marks) and the white dial that is inside the pressuretrol is set at 1 . So cut-out should be 2.5 to 3 PSI from what I understand.
I have been watching the heating cycle a few times and noticed that after 8-10 minutes the pressure on the gauge reads 6-7 PSI and at that point the boiler shuts itself down (I assume the gauge is just inaccurate and system is shutting itself at the actual cut-out I set on the pressuretrol). Not sure if I answered your question, my understanding is still basic!

Just to be clear on how a proper boiler should work. The pressurtrol should not activate during normal operation. The boiler when sized properly should produce steam at a rate that should not dramatically exceed the systems ability to condense it. In your case with a dramatically oversized boiler, it is producing steam faster than the system is capable of handling it, so building pressure is the result. That shuts the boiler down on safety and doesn't fire again until the pressure drops.

This situation is compounded by the inadequate main venting you have. If you let us know how long and what size the mains are we could recommend a proper amount of main venting. This will not solve the oversize problem, but it could help you get more reasonable run times before shut down.

It's so annoying that these people take money from customers to not know what they are doing. pitiful

109A_5

jimmyenz17 said:

@109A_5
I don't remember the pressuretrol setting for the old boiler, the image I attached before has poor resolution to tell the setting.
In the new boiler, the cut-in pressure is set as about 1.5 PSI or 2 (difficult to tell based on the marks) and the white dial that is inside the pressuretrol is set at 1 . So cut-out should be 2.5 to 3 PSI from what I understand.
I have been watching the heating cycle a few times and noticed that after 8-10 minutes the pressure on the gauge reads 6-7 PSI and at that point the boiler shuts itself down (I assume the gauge is just inaccurate and system is shutting itself at the actual cut-out I set on the pressuretrol). Not sure if I answered your question, my understanding is still basic!

Thank you, @jimmyenz17 that tells me two things;
One, the Pressuretrol setting could be lower Cut-In = 0.5 (and not 1.5 or 2)
Two, the calibration of the Pressuretrol is suspect (no surprise there).

@KC_Jones, I thoroughly understand that since I have a slightly undersized boiler and it never goes over 2 inches of Water Column. In my opinion in the eyes of Honeywell a 'trol is a safety device and a 'stat is a dynamic control device. That being said, presently @jimmyenz17 has Pressuretrol that probably can be set to a lower pressure. This may help make the situation more livable until the other issues can be corrected or otherwise resolved.

Is there some reason the Pressuretrol should not be set to its functional minimums ?

PMJ

@KC_Jones ,

I would say in this case the boiler is producing steam much faster than it can get through that small header and that is what is creating the pressure and tripping the pressuretrol. I don't think the entire system is at 6 psi after 8 minutes and all radiators condensing their maximum amount. The header is at 6 psi but the main after it is not.

This is an important distinction and critical to understanding the point I am making.

Jamie Hall

I rather agree with @PMJ here. It would not be at all hard, given that riiser setup, to lose several psi before the steam even leaves the header -- never mind trying to get up the risers to the rest of the system. Those two main vents themselves don't help -- they aren't large enough for the capacity of the boiler, though they may match the mains well enough. Without some rather dramatic repiping, this is going to be a very difficult system to control properly. I'll have to think about how to do it -- some combination of a holdoff timer on refiring the boiler if hit shuts off on pressure, but also a remote pressuretrol as a control device (keeping the pressuretrol on the boiler, of course, as a safety. I'll have to think on this one.

PMJ

Jamie Hall said:

I rather agree with @PMJ here. It would not be at all hard, given that riiser setup, to lose several psi before the steam even leaves the header -- never mind trying to get up the risers to the rest of the system. Those two main vents themselves don't help -- they aren't large enough for the capacity of the boiler, though they may match the mains well enough. Without some rather dramatic repiping, this is going to be a very difficult system to control properly. I'll have to think about how to do it -- some combination of a holdoff timer on refiring the boiler if hit shuts off on pressure, but also a remote pressuretrol as a control device (keeping the pressuretrol on the boiler, of course, as a safety. I'll have to think on this one.

I do think the header must be replaced. It is too small and choking the boiler causing the pressure. It is like me closing the big valve on my header at the main half way or more which would immediately cause pressure in my header. I'm not proposing a control that can deal with that. There will always be more pressure in that header than should be which wastes too much. The flow out must be unrestricted.

I'm saying with big enough header piping to that big main WW3 over replacing the boiler can be avoided.

ChrisJ

So you two feel 2" piping is restrictive enough to cause a several psi drop?

What volume of gas would 2" piping need to cause a 3-4 PSI drop over such a short distance?

For natural gas, I see 23,300 cubic feet per hour for a 1 pound drop at 20 feet.
How many cubic feet of steam per hour can that boiler produce?


I understand that piping isn't adequate.
But picturing that 2" piping with 6 PSI on one side and 1 PSI on the other, that would seem like an insane amount of volume if it's primarily carrying steam.

PMJ

KC_Jones said:

jimmyenz17 said:

@109A_5
I don't remember the pressuretrol setting for the old boiler, the image I attached before has poor resolution to tell the setting.
In the new boiler, the cut-in pressure is set as about 1.5 PSI or 2 (difficult to tell based on the marks) and the white dial that is inside the pressuretrol is set at 1 . So cut-out should be 2.5 to 3 PSI from what I understand.
I have been watching the heating cycle a few times and noticed that after 8-10 minutes the pressure on the gauge reads 6-7 PSI and at that point the boiler shuts itself down (I assume the gauge is just inaccurate and system is shutting itself at the actual cut-out I set on the pressuretrol). Not sure if I answered your question, my understanding is still basic!

Just to be clear on how a proper boiler should work. The pressurtrol should not activate during normal operation. The boiler when sized properly should produce steam at a rate that should not dramatically exceed the systems ability to condense it. In your case with a dramatically oversized boiler, it is producing

ChrisJ said:

So you two feel 2" piping is restrictive enough to cause a several psi drop?

What volume of gas would 2" piping need to cause a 3-4 PSI drop over such a short distance?

For natural gas, I see 23,300 cubic feet per hour for a 1 pound drop at 20 feet.
How many cubic feet of steam per hour can that boiler produce?


I understand that piping isn't adequate.
But picturing that 2" piping with 6 PSI on one side and 1 PSI on the other, that would seem like an insane amount of volume if it's primarily carrying steam.

No way to know the exact numbers without a gage on each side. It is a restriction that shouldn't be there. It is also a restriction right at the source of the steam. It is an orifice actually preventing the full volume of steam being produced from passing through. The dead men always installed pipes big enough that such a thing could never ever happen.

I have the same size boiler with a 4 inch header. If you changed that out with a 2 inch I'd have pressure at all times in that header trying to get steam to the rest of my system. How much I don't know. I do know it would be a total non-starter.

ChrisJ

PMJ said:

KC_Jones said:

jimmyenz17 said:

@109A_5
I don't remember the pressuretrol setting for the old boiler, the image I attached before has poor resolution to tell the setting.
In the new boiler, the cut-in pressure is set as about 1.5 PSI or 2 (difficult to tell based on the marks) and the white dial that is inside the pressuretrol is set at 1 . So cut-out should be 2.5 to 3 PSI from what I understand.
I have been watching the heating cycle a few times and noticed that after 8-10 minutes the pressure on the gauge reads 6-7 PSI and at that point the boiler shuts itself down (I assume the gauge is just inaccurate and system is shutting itself at the actual cut-out I set on the pressuretrol). Not sure if I answered your question, my understanding is still basic!

Just to be clear on how a proper boiler should work. The pressurtrol should not activate during normal operation. The boiler when sized properly should produce steam at a rate that should not dramatically exceed the systems ability to condense it. In your case with a dramatically oversized boiler, it is producing

ChrisJ said:

So you two feel 2" piping is restrictive enough to cause a several psi drop?

What volume of gas would 2" piping need to cause a 3-4 PSI drop over such a short distance?

For natural gas, I see 23,300 cubic feet per hour for a 1 pound drop at 20 feet.
How many cubic feet of steam per hour can that boiler produce?


I understand that piping isn't adequate.
But picturing that 2" piping with 6 PSI on one side and 1 PSI on the other, that would seem like an insane amount of volume if it's primarily carrying steam.

No way to know the exact numbers without a gage on each side. It is a restriction that shouldn't be there. It is also a restriction right at the source of the steam. It is an orifice actually preventing the full volume of steam being produced from passing through. The dead men always installed pipes big enough that such a thing could never ever happen.

I have the same size boiler with a 4 inch header. If you changed that out with a 2 inch I'd have pressure at all times in that header trying to get steam to the rest of my system. How much I don't know. I do know it would be a total non-starter.

I have absolutely no doubt this can easily be calculated.
At this point, I'm not buying the 5 PSI pressure drop on a 2" header.

While the header is being fixed the ridiculous boiler should be replaced with something reasonable.

EzzyT

The homeowner reached out to me, had me come out to the house and looked over the entire steam system.
The boiler is about 25% oversized.
The header is definitely to small along with not being high enough above the the boilers normal water line.
There is about 20’ section of the 3” steam main that is counterflow with no condensate drip.
The main venting needs to be upgraded along with all the radiator vents.