balancing system

Kevin Blair

I tried a search and didn't find what i want, but i bet this question has been asked and answered a number of times: how do I go about balancing the radiators of a one pipe steam system?



I get some, and even most, of them on at one time, but there is always at least one cold one. Right now the back of the house has three cold radiators.



There are 9 radiators total. The one in the dinning room seems to be the key. I am sure it is the first one to receive steam. This evening it heated all the way across. This meant that 5 of the 9 radiators came on. I have tried it with the vent wide open, almost totally closed and seemingly every point in between. When I change the vent setting for this radiator it seems affect all of the others.



With 9 of them, it is hard to isolate variables...anyway, I hope someone has some thoughts on to proceed and get things sorted so that they all come on when they should.



Thanks,

Kevin

Rod

Balancing

Hi Kevin-  You might want to get Gerry Gill's /Steve Pajek's book on Balancing Steam Systems. It's available as a download e-book at the following link:

http://www.heatinghelp.com/products/Books/5/146/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill-and-Steve-Pajek



You might also want to read Dave Bunnell's ("Boiler Pro") Article of 1 pipe steam systems:

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/1551/Taking-Another-Look-at-Steam-Boiler-Sizing-Methods-by-Dave-Boilerpro-Bunnell



Both of these with give you a great insight into balancing your steam system.

- Rod

David Nadle

Do you have main vents

If you don't have vents at the ends of the mains then it will be hard to balance the radiators. If you have good main vents then steam will be available to all radiators at approximately the same time and you can size your radiator vents based on the size of the radiator instead of the distance from the boiler. I assume your thermostat is in the dining room you mentioned. That radiator usually has the slowest vent so it doesn't trip the thermostat too early.

Kevin Blair

Balancing

Thanks for the responses!



The main vents were replaced two years ago, maybe a bit more, after we bought this house. It is actually a two flat with two separate one pipe systems--one for each apartment. The funny thing is that i got the lower one to balance last fall w/o any trouble, but i cannot seem to get the upper--where we live!



I will read Dave Bunnell's article and see where that takes me.



The thermostat is in the dinning room. I actually rigged a temporary thermostat at the back of the house, but all that does is keep the boiler firing longer. The radiators still didn't come on!



The vents in the radiators are new, replaced at the same time as the main vents, but i wonder if the one in the dining room needs to be replaced? 

nicholas bonham-carter

main vents

what type of main vents are installed? the radiator vents should only let the air out of the riser + radiator. the main vents handle the steam chest, and all the piping. low pressure [ounces] helps to speed up the simultaneous arrival of steam to the radiators.--nbc

Kevin Blair

vents

The main vents are Hoffman #3 and the radiator vents are varivalves from Heat Time. All were purchased in February 2008.



This house is a two flat with a finished attic that includes two bedrooms and a bathroom which is essentially part of the second floor unit. The apartments have three bedrooms. There are 7 radiators in the second floor apartment and two in the finished attic.



The boiler is pretty much in the center of the main piping, but the front of the house is a bit shorter run than the back. The front (dinining room, living room, first bedroom and bathroom) radiators all come on, as does one of two in the finished attic. The radiators in the other two bedrooms on the second floor, a bedroom on the 3rd floor (attic) and a back porch off the master bedroom do not come on. These all appear to be connected to the slightly longer run.



If I play around with the radiator vents I can get some of the cold radiators to come on, but others go off. The best I have ever managed is 7 of the 9, with one of the 7 working ones still more cold than warm.

BobC

Pipes

I didn't see any mention of pipe insulation in your post. If some or all of the basement pipes are not insulated that can lead to all kinds of balancing problems. Also check to make sure all the piping and radiators are pitched back towards the boiler.



good luck,

Kevin Blair

insulation

Thanks, I didn't think to add info about insulation and pitch. The pipes are all insulated and the pitch of the raditors is correct. This was all done at the same time that I changed the vents. Thye pipes were missing insulation and a few of the raditors were completely level, not pitched at all.

Rod

Main Vents

Hi Kevin-

     Check your main vents again. I'm not sure you have the right number as the Hoffman # 3 is a Paul vent. (See attached chart)  On each of the steam mains ("runs") there should be a main vent(s).

     The Vari-Valve Vents on your radiators are very aggressive (fast). I would follow Boiler Pro's recommendation:  "Vent you mains quickly and your radiators SLOWLY but completely"

      I should have mentioned in my earlier post. One of the benefits of Gerry Gill's book is that he has listed (and tested) all the common vents (main and radiators, plus radiator traps) and shows their venting capacities at different pressures so it is easy to compare the different makes and model vents. It also has set by step article of balancing.

- Rod

Kevin Blair

main vents

Tanks for the chart. I do plan to download the book tonight.



From the chart it looks like I have the wrong main vents. I am pretty sure these were recommended by the guy who cleaned the boilers for me when we took over the house, but it could be I simply bought new versions of what I found already installed.



Either way, it looks like I should be using 4A or 75. Does Hoffman have a customer service number so that I can call and discuss what would be best?



The varivalves seem to work well, especially in the lower and i can set them to vent more slowly.



I am leaning toward replacing the main vents and seeing what happens.

Kevin Blair

4A vs. 75

Doing a bit of research between the 4A and the 75. I am not sure which one to get. The 4A is less expensive, which is always nice, but I am not sure it is the best choice. I am also going to double check that I hoffman #3 in both places. I only looked at one vent this morning and assumed they are both the same.

Rod

Main Vents

Hi Kevin-

As you will see when you get Gerry's venting book, the Hoffman 4A is much smaller capacity wise when compared to a Hoffman 75 or a Gorton # 1.

I would get the book first and calculate the volume of your different mains and then using the venting info, calculate the venting capacity you need for each main so that they will fill with steam at the same time.  You might want to look into both the Hoffman 75 and the Gorton #1 and Gorton #2  and make a cost comparison. Also take into consideration the clearance available as a Gorton #2 is quite a bit larger than the other two.

    After you have all your mains venting quickly, you can then consider each radiator's individual vent. The Vari - Valves, even on minimum setting, have quite a bit of venting capacity and may still be too big. The Vari-valves along with other radiator vents are rated in Gerry's book so you'll be able to see comparisons.

With your main venting straightened out you should now have all the mains filled with steam and that steam available to all radiators. The idea now, using the radiator vents, is to ration the steam so all the radiators reach their full capacity at the approximately the same time which means you'll have to slow down some and speed other ones up.

- Rod

Rod

Main vents (cont.)

Sorry I didn't see your newest post before I posted my last. The Hoffman 4A has about 1/4 the venting capacity of a Hoffman 75.  The Hoffman # 3 is a Paul radiator vent and is tiny physically when compared to a typical main vent so I think you may have read the number incorrectly which is very easy to do on an old rusty vent! Most of the steam people favor Gortons so I would take a close look at them. Hoffman 75s are good vents but a bit pricey.

- Rod

nicholas bonham-carter

go with a gorton #2 !

pex supply has them, and hopefully they are not in short supply now that winter is here.

start with 1 then see if the end of the dry return gets steam a lot quicker, however if the main is long, you may need more [i have 5 on each of 6 dry returns!]--nbc

Kevin Blair

Goofed on the Main Vent #

Thanks again for all of the help!



Just got home and checked carefully: both main vents are Hoffman 75; I misread the 5 as a 3 this morning on my way out the door. Sorry!



I have set the varivents to pretty much their lowest setting on all 9 radiators. I moved the switch to the closed position and then backed it off approximately an 1/8"



We'll see what that does. In the meantime i will download the book and start to read..

Kevin Blair

Gortons

Thanks! I will see what lowering the setting on all of the radiators does; could be hard to tell as the temp in Buffalo has risen a bit to the mid 50s--was low 40s the last few nights.



The vents would be 2+ years old...any way to know if they are still working?



I can take a picture, but from what i see, the radiators that are not coming on seem to all be connected to the end of the longer run. The one in the attic that does come on is fed from the middle of the longer run, about halfway between the boiler and the vent.



The pipe and the vent feel warm, but the branch line doesn't feel warm. Not sure if this means that the vent is working (i.e., it is warm) or not working. if it is not working, then it would explain the lack of steam going into the branch lines.



I will check on the Gorton #2 and may get one and give it a try.