Steam Boiler not heating main - looking for steam pro to evaluate near boiler piping (Fairfield CT)
I have a SteamMax 125 steam boiler. Boiler fires and makes steam, and the boiler risers/header get hot, but the steam main downstream does not fully heat and the main vent (Big Mouth) never closes. I just added the big mouth last week but didn't seem to help at all.
Some radiators heat (often partially), others lag or stall. Pressure is low (vaporstat).
Near-boiler piping appears marginal:
- Short risers (~18–19″ to first turn)
- Early 90s into the header
- Suspect wet steam / poor separation before the main
System worked in past years but has become unstable. I’m not looking to swap vents or raise pressure.
Looking for a steam-experienced pro to evaluate and likely correct near-boiler piping (possibly a drop header) and advise on return cleaning/skimming as needed.
If you’re a steam specialist In or Near Fairfield, CT, or can recommend one, I’d appreciate it.
Comments
-
can you show us a picture of the near boiler piping? if it worked before it probably isn't the near boiler piping but the arrangement is more important than the lengths.
does @New England SteamWorks work in that area?
0 -
I go further in to Connecticut than Fairfield and its an hour from us. Here to help Cooper. Mad Dog
1 -
i added a big mouth but the steam never reaches it to close it.
0 -
With the boiler off, unscrew the main vent completely.
Start the boiler. When steaming starts, you should feel air coming out of the the hole, and eventually, steam. It comes on fast, don't let yourself get burned.
If it doesn't, something is plugged between the boiler and the vent, and needs to be fixed.
If air does come out properly, something is wrong with your vent.I ordered a pair of main vents, and one was broken from the get-go.
cheers -matt0 -
the header is wrong, the order should be the risers from the boiler, the risers to the steam mains, then the equalizer. you have the risers from the boiler in between the equalizer and the connection to the mains.
i assume this is 2 pipe. it looks like it is a vapor system. it should probably vent from the returns only with the mains venting in to the returns through crossover traps or something similar.
0 -
Hey Matt, I did this test before I added the Big mouth. I did get some air movement, but it never transitions to sustained steam. The
Header and boiler risers get hot, pressure stays low, and the main never fully heats.
That’s why I’m suspecting steam collapse / wet steam rather than a hard blockage or bad vent.- Some of my radiators are heating… some partially, some fully, there is low pressure and no hammer noise. The Header and risers do get hot but the main vent never closes.
0 -
Appreciate that — agree the header geometry is suspect.
Boiler risers are short and steam seems to collapse before filling the main.
I’m primarily looking to correct the near-boiler piping (possibly a drop header) so the system can make dry steam again.
Once that’s resolved, I can revisit venting strategy if needed.
0 -
Someone like @Mad Dog_2 or @New England SteamWorks would be the ones to figure it out. Tell them what is happening but don't tell them how to fix it. There is likely some knuckleheading that happened in numerous areas and though ideally the header should be fixed, it may not be the problem.
This is 2 pipe and you don't have steam traps on the radiators, right?
0 -
yea two pipe system. But there are traps. I initially replace one with TFW-2507. Didn’t seem to fix the problem. ( only first 1/4 of the radiator heating up)
New England Steam Works actually is the one who told me about this site/forum because I was too far outside his service area. It also sounds like Mad Dog is more of a consultant vs someone who actually does the work?? I could be wrong. But I’m looking for a steam competent plumber to remedy this. I called one company and $200 later, they said I needed to replace all the traps on the radiators that weren’t working.
0 -
trap problems usually cause a radiator other than the one with the bad trap to not heat. the bad trap lets steam in to the returns and that steam in the return keeps a different radiator from being able to vent and heat.
the black rectangular box thing I think is an air vent for one of the vapor systems, it possibly is stopping steam from venting out before it gets to the vent, but if the system is working properly there should never be steam in the returns in the first place so vents on the returns should never close.
I'll let @Mad Dog_2 say what he does or doesn't do. I think some of the new york companies also work in CT. If the traps are ancient most pros would just replace them rather than going looing for a bad one if they know one or more are bad and traps capsules are not inexpensive. if it is still equipped with the vapor valves on the radiators and you keep the pressure very low, around 8 oz/in^2, it should function without the traps.
0 -
Gotcha, yea I think I've taken my DYI skills to its limits. It snowed in CT this past weekend and its COLD in this house. The second floor is much warmer but its pretty chilly on the main floor. Radiators just aren't kicking off heat like they should. Its been tough to find someone who seems to know steam. So I figured I'd give this forum a try. I appreciate all the help and feedback, but at this point I need James Watt in here now.
1 -
Check the gas pressure. Boiler might not be making enough Steam. Pretty common. Gas control might need adjusting or replacing. Could be other things as well
1 -
You can check the firing rate by clocking the test dials on the gas meter.
—
Bburd
1 -
does the boiler cycle on and off on the vaporstat? if the boiler is producing full output and the system isn't consuming it because the air can't get out then the pressure should rise and trip the vaporstat off, assuming it is set to something reasonable. also could be the pigtail to the vaporstat is clogged and the pressure is getting too high sending steam and water places it shouldn't be and keeping the system from heating.
0 -
Here is the webster catalog. I think that device is the vent trap on page 17:
there is another version out there that isn't from during wwii that doesn't have iron and steel substituted for brass.
0 -
Thanks for these suggestions and info. I'll pass it all along to the steam pro who eventually comes to take a look.
0 -
how old is the boiler?
any chance you're seeing steam plumes from the chimney when you're firing and steaming?
known to beat dead horses0 -
@CooperFamily Call @Mad Dog_2 or PM him he does some travelling. Based on past experience in Fairfield County steam people are in short supply.
Proof that Fairfield is short on steam people is that you have a boiler that is piped wrong, all wrong.
That is or was a vapor system and a really old one at that looking at those old fittings.
I also might question the height of the boiler return behind the boiler it could be too high and cause hammering.
1 -
that check valve above or at the water line is going to do weird things. it originally was there (with a boiler with a much higher water line) to work with the webster boiler return trap to equalize the pressure in the boiler and the return to allow the water to return to the boiler.
0
Categories
- All Categories
- 87.3K THE MAIN WALL
- 3.2K A-C, Heat Pumps & Refrigeration
- 61 Biomass
- 428 Carbon Monoxide Awareness
- 120 Chimneys & Flues
- 2.1K Domestic Hot Water
- 5.8K Gas Heating
- 114 Geothermal
- 166 Indoor-Air Quality
- 3.7K Oil Heating
- 77 Pipe Deterioration
- 1K Plumbing
- 6.5K Radiant Heating
- 395 Solar
- 15.7K Strictly Steam
- 3.4K Thermostats and Controls
- 56 Water Quality
- 51 Industry Classes
- 50 Job Opportunities
- 18 Recall Announcements