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It takes HOURS for many radiators to get hot, why?


Good day,

I am reading "We Got Steam Heat" and Dan advises to post my question here if I get stuck. 

Here goes:

I've lived in our 1931 brick exterior and plaster interior home since 11/2019.  It is a single-pipe steam system connected to 38 radiators on 3 levels. Basement, 1st and 2nd floors.  The home has double insulated windows, storm doors, and 6 fireplaces. Only one is used regularly. 2, are covered with repurposed dining table protector pads. The flue's are always kept when not in use. 

Every winter it takes on average 3 hours for several bedroom radiators to get hot. 

The front door faces south and the boiler is below & slightly northeast of it. The thermostat (TS) is in the dining room (east of the entrance) on the south end of the wall directly above the boiler. This room is a constant +/-70* year round.  The 2 radiators are plugged. I presumed it was to keep the room from getting too hot and interfering with the TS. The radiant heat from the boiler already interferes. I have to set the heat ON to about 74* for it to turn on. Then it is on and on and on and on..... for hours until the 6 radiators on the 2nd floor (west and northwest of entrance) get hot. By which time we've already plugged in the heaters. 
On the 1st floor, northeast of the entrance it takes just as long for those 4 radiators to get hot. Again, heaters plugged in.  

The living room is west of the boiler & has 3 of 5 radiators plugged. It takes a while for those to heat up as well.

The only radiators to heat within a 1/2 an hour are located in the center of the home east & west of the entrance on both levels. 

The master bedroom has 2 of 4 radiators plugged. 

I honestly don't know how long it takes for the basement radiators to get hot.

All but one of the radiators have Vari-Valve vents. The one that isn't is a longer nipple topped vent.

Just last month I found 2, Gorton 1 on the main lines that are northwest of the boiler. I changed one this week. The other still made the klinking sound and I could blow air  through it. The line with the working vent has insulation that starts about 30" north the vent. There is no insulation between the vent and the boiler. It runs close to the ground and comes up to the ceiling . I will insulate that pipe this week. These to vents are don't he lines that lead to the 1st floor radiators on the east side and take hours to heat.

Some other quirky things are there are several hot spots under the floor upstairs. on the the bathrooms floor is so toasty warm year round. As is inside a closet just across the 30' wide hallway.  

(Pictures of the PEX tubing) The previous owner installed central air and radiant heat systems on the 1st floor. Central heat and AC for the diningroom, kitchen, powder room and 2 bedrooms. These areas are located east of the entrance. The radiant heat is only in the kitchen.

I never use the radiant heat. Don't really need to as the hot water passes the circulating pump and half the floor is always warm. I turned that off year 1. However, the hot water passes both circulators. So I keep the valves closed on the central air system when I'm not using it. (That's really too much work). 

There is no water hammer or steam spitting from vents. There is a ticking sound for a few minutes as the heat is rising to the second floor maste bedroom. it stops after a few minutes.  I believe that to be the pipe expanding around the floor or framing holes.

He is my concerns: 

My family has already mentioned that it's past October 15th. Way past. 

I just payed over $1K to top of my 550 gallon tank, after filling it up in September. It has used a 1/4 tank of oil just to have hot water ready to be used. 

I think the pressuretrol is set too high. 

Here are my questions:

1. Why does it take so long for the steam to get to all the radiators. 

2. Why are the radiators plugged? Should I put vents on them? If so, which vents do you recommend?

3.Should I lower the pressuretrol setting to .5 or 1? Or change it to a vaporstat? 

4. Can I move the TS to the opposite side of the wall? That would put it inside the entry about 7 feet from the door. This entrance has 2 quick heating radiators on the south & north sides of the interior wall.  It's not a drafty hallway and we hardly ever use that door. Or move it to the 2nd floor directly above it in the hallway or inside the master bedroom?

5.Why are there hot spots on the floor? Is that normal for a steam system?

6. Can or should I convert to gas?    I do have a Con Edison gas line in the home for the dryer.  I see the line runs extra lengths in 2 directions. One towards and under the kitchen and the other towards the boiler room.

7. Should I replace the TS? It often stays open when the temp has reached its set temp. 

8. What is a petrometer and what should I know about and do with it?

9. Lastly, What changes should I make before I turn the heat on for the season?

Thank you all for reading this novel. And even greater thanks for your time to reply. Have a great day.



  • Jamie Hall
    Jamie Hall Member Posts: 23,322
    It wouldn't hurt a bit to try the pressuretrol at a lower setting -- just don't go all the way to bottom, as they tend to come apart when you do. And that would take 10 minutes.

    Second, I would wonder -- what thermostat is in use? If it's one of the newer digital ones, is it set for steam?

    Third -- lack of main venting. And insulation. Both of those problems will really make trouble getting steam to more distant radiators. A Gorton #1 is a good vent. It's too small, even for a relatively short main. You do have a headroom problem, but a Gorton #2 would be much better -- and you need them on all the mains in the basement.

    Radiator venting -- make sure that the nearer radiators have slow vents on them.

    The hot spots may be uninsulated sections of main or runout; if you are not losing water in the system that's probably what they are. If you are losing water, though, they might be leaks in the piping.

    So -- how much water are you using?

    Also, check the pitch of all the pipes that are even remotely horizontal. An incorrect pitch can make steam very slow -- if not block it entirely.

    You mention thinking of changing to gas. Don't bother. Even if a conversion burner were available for that boiler, it won't make a bit of difference in delivering heat out into the system. The boiling water in the boiler doesn't know or care what the heat source is!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 9,662
    Can you show us a radiator with the cover off? Are all the radiator valves either all the way open or all the way closed? I assume this is 1 pipe steam.

    Is the hot water loop also heated by this boiler?

    When was the burner last serviced by someone that knew what they were doing? It could be underfired or the boiler could be plugged up with soot so it isn't heating the water fast enough to boil it.

    If piping has sagged or some of the returns are plugged such that water is held in the piping that will stop the steam from progressing.

    There may be some device under the asbestos that has failed, it may not be a simple system.

    Most of that insulation is asbestos in case you were not aware.
  • ChrisJ
    ChrisJ Member Posts: 15,702
    I can't comment on the rest, but,
    It looks like the barometric vent is up against lattice. That's no good if you want it to work correctly.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • AdmiralYoda
    AdmiralYoda Member Posts: 629
    edited November 2022
    When was the last time a Steam Pro came and did an inspection and tune up? Mechanical problems are one thing...but with a boiler that old I'd want to be confident it is running at safe pressure with safety mechanisms in place and is burning oil properly.

    I'm not a pro, just a homeowner enthusiast but one thought did come to mind. Perhaps the oil burner is not sized correctly for the boiler? It may take that long just to heat the water up!

    A couple things to check:
    1. Get yourself a low pressure gauge, something like 0-3psi. I'd want to verify that the pressuretrol is operating and the pressure is not too high. If it is high, which I suspect it might be....adjust it down as much as you can. Steam likes low pressure. 1-2psi at most usually, ounces are even better.
    2. When there is pressure and steam is being made, carefully take one of the air vents or plugs off of the radiators. Plenty of hot steam should come out. If barely any airflow happens make sure the radiator valve is opened.

    It isn't advisable but some people have tried to control the amount of heat a radiator can produce by closing the radiator valve. Way better ways to control too much heat.

    Also check to make sure any gate valves (if any) on the mains are wide open.
  • neilc
    neilc Member Posts: 2,703
    # PIGTAIL ,

    take the time to check, or just replace the pigtail,
    that's the looped pipe under the Ptrol,
    that one looks to be steel, try and find a brass one,
    the steel is more prone to plugging,
    the pigtail needs to be free breathing back into the boiler, or in your case that piping,
    needs to be free breathing so the Ptrol, and your gage, can "feel" the boiler pressure, .
    as you reassemble the piggy and Ptrol, add a little water to prime the new pigtail loop,

    and yeah,
    lower that Ptrol setting to as low as it can go, and reliably cut back in, try lining up the indicator to the 0.5 on there,
    inside the cover there should be a differential wheel, it should be set to 1,
    this will give you a cut in of ~ 0.5, and a cutout ~ 1.5,

    when the boiler is firing,
    what do you see for pressure on that gage?

    can you see the water line in that sightglass?
    and does it bounce much? more than a 1/2 inch, 1 inch ??

    those circulators,
    they should be set with the motor bodies horizontal, not vertical like you are,
    dirts will settle down to those bottom bearings,
    you don't want that,
    known to beat dead horses
  • clammy
    clammy Member Posts: 3,111
    Aside from above comments and lack of any venting on some radiators and under venting of your mains the bigger question is has anyone done a water side flushing of the boiler ? As old as your boiler is if no one has flushed out boiler you may have a large build up of mud which greatly reduces the boilers ability to produce steam . With out vents on every single pipe radiator they will receive little if any heat . I believe the previous home owner possibly removed them in a attempt to lower there fuel usage . This some thing that I ve come across over the years not un common w older homes .Aside from others comments it’s also would make sense to have some one clean the fire side of the boiler and check the burner and it’s firing rate or if the boiler has a rating plate on it or against the edr of your existing radiators . Reducing the burners firing rate may also have been greatly reduced again in a effort to lower fuel consumption . I would say that your boiler is way into its twilight years and w fuel at what it is and rising keeping a boiler that possibly about60 % eff and hoping to use less fuel and heat your whole home without going broke may be fairly hopeless . To get everything up and working you first need to install radiator vents in all radiators and replace all main vents also . You would be wiser to look to have your steam boiler replaced basically due to its age ,face it it’s 85 years old and at that point not many would want the liability of it having a total failure on there clock and be left holding the bag . The other fact is that boiler was installed when oil was just about free ,it ain’t free anymore . This is the best honest free advice I can give either way your gonna pay weather it’s the oil guy and still be uncomfortable or hopefully a honest mech w steam knowledge not a knuckle head but there only so much your gonna do w that beast and even if you get it all up and working great your fuel consumption is not going to make you feel so good .
    Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • MikeAmann
    MikeAmann Member Posts: 998
    Thanks for the pics. It feels like I just took a journey in the WAYBACK MACHINE.
  • TonKa
    TonKa Member Posts: 104
    edited November 2022

    The line with the working vent has insulation that starts about 30" north the vent. There is no insulation between the vent and the boiler. It runs close to the ground and comes up to the ceiling . I will insulate that pipe this week.

    This sounds like you are describing a wet return. Insulating a wet return couldn't hurt, but is not crucial to the system.

    Straighten out your main venting, then your radiator venting. I think you'll be pleased afterward. I know I was in my house. 🙂

    This should help:

  • mattmia2
    mattmia2 Member Posts: 9,662
    edited November 2022
    You could just have a lot of bad vents on the radiators, you can try unscrewing a vent on one of the radiators that isn't heating and see if you get air and then steam within 5 minutes to half an hour or so. Lack of main vents will slow the radiators heating but by tens of minutes, not hours. If you don't you have other issues like water is trapped somewhere or the boiler is underfired.
  • 19311pipesteam
    19311pipesteam Member Posts: 3
    My sincere thanks to everyone that offered great advice. I am having the boiler cleaned & serviced as needed on 11/11. I still haven't turned on the heat. I hope the replaced main vent works. I will follow all the suggestions and hope for a quickly warmed outcome.

    The water line is visible in the glass tube. it is about an inch high with the system off. I will check the gauge when the boiler turns on to heat the hot water tank. I'm not sure if that will make the water move.

    My first winter here I did replace several vari-valves that weren't working. I am sure the dining room radiators were plugged to keep the thermostat working. But in reality, I have to turn on and off the TS manually. I am strongly considering moving it upstairs.

    Thanks for your honesty Clammy. I would like to replace this old timer with gas. I just don't know if a gas system can be fitted in without changing the radiators. Ort maybe change to hot air as 1 of the 3 central AC units gives heat too.

    Does anyone have an explanation as to why there are hot spots on the floors?

    Thank you for your consideration & time.

    Be well, warm & healthy
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,210
    Clammy is on the money here, as usual.

    Clean the mung out of the water side of the boiler. That means trying to get into the med leg and cleaning it out.

    How long does it take the boiler to start steaming? Check the firing rate of the burner. If it's too low the water will simmer forever without steaming. Check the stack temperature of the boiler and see if your fire's not going right out of the chimney. The dampener can be set and baffles added to the fireside to slow the gas flow and lower the stack temperature assuring more heat is going into the iron.

    Get all the venting straightened out.

    Sounds like the thing is under fired to me. Those old Mills boilers required a huge fire to heat that iron, and oil men don't always know what they are doing in the quest to economize steam systems.

    Save your money and consider replacing that thing. I'd bet the payback would be only several years.
  • propmanage
    propmanage Member Posts: 15
    All good information but winters coming fast and you should really get a seasoned steam professional in to go through everything. Good luck.
  • bburd
    bburd Member Posts: 917
    @19311pipesteam The choice of fuel has nothing to do with your radiators, those can stay in place if they are in good shape.

  • AdmiralYoda
    AdmiralYoda Member Posts: 629
    @19311pipesteam After your heating pro gives you the results of the inspection and tune up, it would be appreciated if you could post them here.

    Also, I'm sure the real steam pro's would love to pick this person's evaluation apart!

    Did you go with a local HVAC company or a steam pro from the "find a contractor" feature on this site?
  • 19311pipesteam
    19311pipesteam Member Posts: 3
    Hello eveyone.

    I had the annual service done on Friday stuff was cleaned & filters changed. The steam pro I used is the long-time service company for this home that is not listed on this site however, this not-so-old "dead man" did say he earned his steam education working with Dan for about 5 years.

    He did lower the both components of the pressutrol to about half of what it was. I showed him where the main vents are. He agreed with my having changed it. He confirmed that one of the 2 was on the return. He informed me that there are 2 main lines going to opposite sides of my home. Unfortunately, we couldn't find any vents on the second line as the basement was finished entirely in a Tudor stucco when built. He believes the vents we found were added [years] afterwards. He recommended that I close the vari-valves mid-way on all the radiators I know to heat fast and see if that helps push the steam to the cold rads.

    The boiler was left on at the end of the service and he recommended that I take notes of what happens at every radiator.

    I did and the following occurred: Heat hit the coldest rooms within 30 min. may have been sooner but I was checking other things. I found one of 1 of 2 radiators in an upstairs bedroom cold, the radiator in the attached bathroom was cold and the radiator next in line (1 of 2) in the next bedroom was cold. But the 2nd radiator was piping hot.

    On the 1st floor, I heard steam hissing from a radiator that looked plugged. I haven't yet removed the wall panel to see what going on.

    I just had a meeting this morning with a pro to discuss options for converting this morning. He looked at my system and said, "wooooohhh". It was a short meeting. He informed me that his company may not even be able to handle an install like. He will call me with some options or names of companies that may be able to help. If conversion to update or change fuel source isn't in the best interest of the comfort of my home & wallet, then I will have to clean and update every part of the system so that we can be economically warmed.

    Otherwise, I'll have to start using all 6 fireplaces.


    Can anyone suggest how I might be able to replace the Gorton 1 for a Gorton 2 in the second to last picture above? It is a tight fit.

    I am also going to replace the radiator vents on the cold radiators. Should I try Gortons or stick with Vari- Valves?

    I greatly appreciate all the advice and information.
  • mattmia2
    mattmia2 Member Posts: 9,662
    You'll need to find where the vent is at the other main and I suspect it stopped working long ago or is sized for coal. An IR camera might help trace the pipes and give you some ideas where to make a hole.

    For the boiler replacement work from the steam guy and see if you can find someone that understands the job, either that guy or someone he recommends. You should still carefully vet whoever you pick but it sounds like that is a good place to start. Your job is both big and technically difficult. It is still by far cheaper than abandoning the system with the right steam pro but it will require someone who can look at and understand the whole system.

    You have to potential options for the vent. If you are lucky you can turn that elbow in the main a bit clockwise and get some clearance to unscrew the vent then turn it back after you replace the vent. Otherwise you'll have to make a little hole in the ceiling.