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Balancing one pipe steam radiators

Don_175
Don_175 Member Posts: 100
We have a house with one pipe steam system. The mains are vented with big mouth vents. 
There are various cast iron radiators throughout the house. Most are columnar. There is also a long tubular and a few cast iron convectors. 
They all have Ventrite #1 vents. 
I read the excellent article on the wall about balancing based on EDR and CPM based on radiator size.
our house has crawl spaces so it would be very difficult to measure the pipe lengths as they travel around.
Dan’s article mentions just using radiator size for balancing and not how far they are from the boiler. 
I have a chart I found that gives EDR for each radiator type. 
The gist of what I’m thinking is to open up the vents of the largest radiators based on EDR and turn down the ones on the smallest ones, with the ones in the middle sizes would be set between the settings of the smallest and largest ones. 

Does this seem reasonable, or should I also factor in distance from boiler in a rough way, maybe turning up a notch the ones that are furthest away. Just trying to do this systematically. 

Thanks very much. 

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 19,907
    You have done the most important part -- main vents on the steam mains.

    There are probably as many approaches to balancing the radiators in a one pipe steam system as there are people trying to do it -- maybe more. It is possible to get all mathematical about it. It's also possible to get all hands on. Or somewhere in between.

    There is, however, one key principle to keep firmly in mind: there is a very definite upper limit to how fast a radiator can heat, and therefore an upper limit to how fast a vent can be and be useful; anything beyond that is limited by other factors. However, there is no lower limit, and below that maximum rate the speed and heat output is controlled by the radiator vent, once steam gets there.

    So... if you of the more hands on approach (I am!) what is needed to balance is to slow down the radiators in spaces which are warming than you want them to be -- without, of course, letting them get too cold. As you slow those down, the radiators you haven't played with yet will tend to put out more heat, since what happens at one radiator will affect, to some extent, all of them. Eventually you may find that you do need to speed up a few radiators -- but keep in mind that there is a upper limit to that, so slow the over ambitious ones down first.

    Of course, as a starting point, a bigger radiator should, all else being equal and the radiators matching the spaces well, a bigger radiator will need a faster vent, so that's a place to start at least.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Don_175
    Don_175 Member Posts: 100
    Thanks Jamie. I have been kind of doing the balancing by feel. If a room heats up too quick, I turn the vent down and vice versa. I will do the calculations to get an idea of the different sizes and then use that as a baseline before adjusting them. Some are a little difficult to figure out. The tubular one we have must be 6 feet wide but only 2 feet tall. But the columnar ones, which are much taller are maybe 3-4 feet wide. I'd assume the tubular one has more mass, but I think the calculations will help give me an idea.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,566
    A low pressure gauge will show whether the capacity of your main venting is adequate. Strive for under 2 ounces, as the air is escaping. The aim is to get steam arriving at each radiator at the same time, with generous main venting, and slower radiator vents.
    The radiator EDR measurements will be useful in determining if the boiler is properly sized.
    Are your supply pipes insulated?—NBC
  • Don_175
    Don_175 Member Posts: 100
    Yes. All pipes in basement are insulated. 
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 790
    VentRite #1s can be adjusted from completely off to about a #5. Depending on the layout of your house, you may need more capacity at the radiators farther from the main, like on an upper floor. The guys on HH have their favorites. Just avoid knockoffs...you get what you pay for.

    Assuming you have one thermostat, is it in the coldest room in the house? Dan's books talk about that. It worked for me.

  • Don_175
    Don_175 Member Posts: 100

    VentRite #1s can be adjusted from completely off to about a #5. Depending on the layout of your house, you may need more capacity at the radiators farther from the main, like on an upper floor. The guys on HH have their favorites. Just avoid knockoffs...you get what you pay for.

    Assuming you have one thermostat, is it in the coldest room in the house? Dan's books talk about that. It worked for me.

    Our Ventrites go to 8 on the dial. We have a thermostat with remote sensors. I put one in the coldest room, and it felt nice. The other rooms ended up about 5-6 degrees warmer. Maybe those are the ones where I should turn down their vents

  • Jamie Hall
    Jamie Hall Member Posts: 19,907
    Don_175 said:

    VentRite #1s can be adjusted from completely off to about a #5. Depending on the layout of your house, you may need more capacity at the radiators farther from the main, like on an upper floor. The guys on HH have their favorites. Just avoid knockoffs...you get what you pay for.

    Assuming you have one thermostat, is it in the coldest room in the house? Dan's books talk about that. It worked for me.

    Our Ventrites go to 8 on the dial. We have a thermostat with remote sensors. I put one in the coldest room, and it felt nice. The other rooms ended up about 5-6 degrees warmer. Maybe those are the ones where I should turn down their vents

    That's where I'd start, anyway.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 790
    The number 0 - 8 is only a scale from shut to fully open. The #5 I mention has to do with how the different size radiator vents are characterized relative to capacity. If you want to learn more look at the tables in this:

    https://heatinghelp.com/systems-help-center/balancing-steam-systems-using-a-vent-capacity-chart/

    It appears you are on the right track. Satisfying the coldest room is, in my opinion, a good beginning, then you can tweak the others. Just remember each time you change a setting or valve, you may affect other radiators in the building. Once you get through the exercise, it should work. In the spring and fall when demand is different from the dead of winter the performance of the system may be a bit different, but that's a minor issue and isn't worth changing settings for the shoulder seasons.

  • Don_175
    Don_175 Member Posts: 100
    The number 0 - 8 is only a scale from shut to fully open. The #5 I mention has to do with how the different size radiator vents are characterized relative to capacity. If you want to learn more look at the tables in this: https://heatinghelp.com/systems-help-center/balancing-steam-systems-using-a-vent-capacity-chart/ It appears you are on the right track. Satisfying the coldest room is, in my opinion, a good beginning, then you can tweak the others. Just remember each time you change a setting or valve, you may affect other radiators in the building. Once you get through the exercise, it should work. In the spring and fall when demand is different from the dead of winter the performance of the system may be a bit different, but that's a minor issue and isn't worth changing settings for the shoulder seasons.
    Thanks! Here is what I did for a start. I used the chart to determine EDR for each of my radiators. The largest was the tubular at 81. I put that vent at 8. I then went through and figured the fraction for each. A few had EDR of 40 so I see their vents at 50%, or 4. However a couple of rooms where the radiators were still cold, I upped their settings. There were two which should have been set at 4, but because the rooms were cold, I set them to 6. I then plan to go around and tweak them as I see how each one heats. Does this sound reasonable? Thanks 
  • ethicalpaul
    ethicalpaul Member Posts: 3,885
    It's reasonable! My preferred way would be to set all radiators low (like 2 in your case) then slowly increase the ones in the rooms that turn out to be colder than I want them.
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • Don_175
    Don_175 Member Posts: 100
    Would it make sense to go around with my infrared thermometer gun to check each radiator to see how they are heating? If so, when should I do it? When they first start to heat?
  • mattmia2
    mattmia2 Member Posts: 6,591
    Temp of the room is a better indicator. That will better compensate for the different heat loads of the rooms if the radiators aren't all perfectly sized.
    bburdDon_175
  • Jamie Hall
    Jamie Hall Member Posts: 19,907
    Don_175 said:

    Would it make sense to go around with my infrared thermometer gun to check each radiator to see how they are heating? If so, when should I do it? When they first start to heat?

    They will all be right around 212 to 215 anyway. What may differ is how much of the radiator is hot.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Don_175
  • dabrakeman
    dabrakeman Member Posts: 284
    I just get some exercise and run around the house using my hand to determine the % fill on each radiator. Usually when my wife is not home so she doesn't worry about my mental state. I started off adjusting my adjustable vents so that each radiator got to 50% fill at roughly the same time, starting off with them pretty slow initially. It took a number of trials to accomplish this. Then, of course I noticed that the actual heat in each room varied. I think that if all the radiators in the house were original and no major modifications were made in the house since it was built chances are even heating of the radiators would lead to somewhat even heating of the rooms. In my case over 132 years I know that some radiators had been changed, moved around and one eliminated. My kitchen for instance I see evidence that it probably originally had a lower but much longer radiator that extended the full length of the 2 West windows on that wall. Now stands a single taller radiator rising above the sill level (which they typically wouldn't have done in original construction) and I estimate to be of considerably lower EDR than what might have originally been there. Someone probably wanted more usable wall space in the kitchen at some point... In the adjacent mud room a small radiator was removed. Between the two I have a hard time keeping this west side of the house warm relative to the rest. So, I basically vent that kitchen radiator such that it will just about reach 100% fill on my typical max cycle time of 30 minutes. At the same time my upstairs rooms tend to overheat when at balanced fill rate with the downstairs radiators and we like the bedrooms cool anyway so those get slowed down considerably.

    My point of all this is 1) I think it advantageous that you have good quality adjustable radiator vents that will allow you to dial in your optimal balance with some patience, and 2) depending upon the unique situations within your house (room radiation to heat loss) and your personal desires for room to room temperature you "may" find in the end that correlations between vent rate and either radiator size or distance from boiler are more minimal than expected. Just don't over vent and try to avoid venting a radiator such that it completely fills on what you would consider a long but still somewhat normal cycle since routinely closing on steam can lead to vent failure and other issues. If your boiler is properly sized and the radiators and home pretty much original, then your "balance" should bend up a little more balanced to EDR than mine;)
    Don_175
  • Don_175
    Don_175 Member Posts: 100
    Excellent advice! Thanks