Why can't I get the two sides of my house heating at the same time?

How long and what diameter are the Mains? Hoffman 40 is a slow radiator vent and the 75's are main vents but two of them are good for maybe 15 to 20 feet of 2" main. The last thing you want to do is plug either of those vents. You need to use some larger vents and enough of them, on each main, based on their length and diameter to balance the flow of steam. My guess is you have more radiators and/or larger radiator vents on the faster main than on the slower one and steam, taking the path of least resistance is going that direction. Put the correct amount of Main vents on each main and then balance the radiators. Vent mains fast, radiators slowly.

@Ps44. Are you sure that the 75's are still venting? They may have died a quiet death.

I ve seen this issue on a few occasions usually what I have found is one main has more rads on it thenthe other ,is the main that is slow to heatwave less rads on it ? The easiest way to explain is what I have experienced which is your quick to heat main must have to much venting on the rads in comparison to the hard to heat . I would count how many rads are on each main you will likely find your quick main has after add up your rad and vents much more and this is what messing it up . I know this sound s weird but remove the main vent on your fast main plug it and chk your results . Personally I would trash that Hoffman 40 and put a 1 gorton on each main to start and it still a issue then put 2 on your hard main and one on the quick main. Have all your rads vents been update recently ? I always suggest replacement at a max time of 10 years after5 they owe u nothing .if your strapped for cash then go to the depo for maid o mist cheaply vents and use them to get semi balanced and as they go replace w gortons . I do suggest on main don’t waste your time w cheap just get gortons main vents aside for Barnes and jones big mouth the rest are just garbage .i once years ago had a difficult 1 pipe balancing job took we a few try’s but it came to me .i was unbalanced because I had far more vent capicatiy on one main compared to another main vents had very little to do it had to do with hi pressure goes to low and hi pressure will always go the path of least resistance which was the main w most of the rads and most of the venting .installed a straight # 5 or 6 on the big main and 2 gorton main vents on the short went right into balance ,it took me a while to see the light and it wasn’t in a book trial and error and some head scratching now it’s in the skull crap and in the bag of cure all’s peace and good luck clammy

You need to get the mains both heating to the ends before any radiators get steam.

If this means having four big mouth vents on one and no vents on the other so be it

In my house I have a short main with a single Gorton 1 and the other 29' main has 5 Gorton 1s.

If I vent the short main which comes off the header first, too fast it still steal steam for a while. That's no good.

Where ya located? Maybe it's time to bring in one of the guru's from The Wall, rather than keep throwing money and parts at it.

There are several contractors located in Brooklyn on the Find a Contractor page. https://heatinghelp.com/find-a-contractor/state/NY

One of them, https://heatinghelp.com/find-a-contractor/detail/newtech-energy-inc, actually says,

Sounds frustrating @Ps44

Hope everything works out sooner rather than later!

I have a 1920s vintage two family with a supply pipe and return to the front rooms on both floors and a second supply pipe and return to the back rooms of the house. The short version is I have owned the house for 30 years and found out the upstairs front living room never got to 70 degrees, even though the rest of the house was warm enough. Once I became aware I did a bunch of things to try to straighten it out...too numerous for now. The back of the house has shorter runs and was heating up much faster than the front, where the thermostat was located.

I haven't read all of this thread, but one thing I thought was contributing to my problem is there is a main vent on each of the two returns, but they are connected about a foot apart. I thought there might be a possibility that the back section was venting through its vent and because it was shorter, it was also venting through the vent on the return from the front supply. This past summer I repiped the back return to go down to the Hartford loop, so the column of condensate in the return would prevent the venting of the back through the vent for the front, letting the front vent more quickly.

Have you looked at the report that has a list of the venting capabilities of the multitude of radiator vent valves and main vent valves? The title is, "Balancing Steam Systems...Using a Venting Capacity Chart". I made a table and chart of the venting capabilities of Gorton, Maid O'Mist, Vent Rite and Heat Timer vents from the data in the tables. I had been using Heat Timers only to find out that when they are set at minimum, they still pass about a #5 amount of air/steam. I bought a bunch of Maid O'Mist vents and way too many orifices only to end up with using the Vent Rites because they could be adjusted down enough to get everything pretty well balanced.

I attached the Excel spreadsheet and can explain how to read it if you need help. The house is about 1000sqft on each floor so it is not that large and I had to set the Vent Rites at fairly small openings. Again there's a lot more to this story and if you are interested or want some reading to help you fall asleep, go to Strictly Steam and look at "Converted Two Family" and "Over Venting" .

There's another thread about thermostats and I also replaced my round Honeywell thermostat with their wireless thermostat with wifi capability. It cost $300 or so, but now I can monitor using the app and don't have to leave the basement if I want to run the boiler when I am in the basement.

I apologize if this seems rambling and hope it is helpful to you and anyone reading my comments.

That's great. If you look at one of my threads, I failed at doing some "surgery" on my returns and had to patch it for the remainder of the winter. Then I got noise and found a support strap was not connected and I had no idea when it came loose. I checked the slope and it was wrong, rehung the strap and the noise went away.

If you have the time, the chart/table on venting is an eye opener...I now have lots of extra vent valves that I will never use.

Happy New Year.

Returns should never be tied together above the water line. It allows steam to move between mains/returns close vents.

@dopey27177, the second picture shows exactly what you just stated. Look at the first picture, which is before the modification and you can see the elbow and tee where the two returns come together and there is only one copper line down. The second picture, which is harder to see the details, shows the two returns separated and a second copper line going down.

You just restated my case as to why the second arrangement is correct. I came up with it on my own through trial and error and some speculation. I was pleased that my Westfield consultant agreed and now you also validated my conclusion and modifications.

I am a retired mechanical engineer who worked in the US Nuclear Navy program for 38 years. I started my career working on the USS Los Angeles reactor plant design in the late 60s, qualified on a submarine nuclear power plant, operated it, trained sailors on it, went through 2 refueling/overhauls (one as a shift supervisor, the other as mechanical engineering manager) and spent years in many other parts of the business.

All that being said, while I learned a lot about nuclear power plants, when I bought my steam boiler heated 1920s vintage 2 family, it was a totally new learning experience. Wow!

I fell into Dan and this web site and have found it to be a tremendous resource with highly knowledgeable people contributing immensely important information to those of us involved in this technology.

The Gill/Pajek report was another eye opener which pointed me to the ultimate venting solutions for the situation with my house.

You might enjoy reading my threads.

@SteamingatMohawk and @dopey27177 , Thank you both for your service. My great grandfather and great uncle worked the Adm. Rickover on the Nautilus Project at EB in Groton. The USN has a remarkable record of safe nuclear power.

And yes trying to reverse engineer to steam's most basic elements can be daunting, steam heat is almost completely counter intuitive.

I do have an additional Gorton on the front line right after the last radiator tap off, so its essentially at the beginning of the return line. I think that helped a lot. I tried many different venting arrangements, including putting 2 Gortons on a tee off the main line. The second didn't help. I did all my work last heating season, except I separated the two returns over the summer. It seems to be operating fine now.

Thank you, but I didn't earn your thanks militarily, because I was a civilian. I was able to go home to my family every night, unlike the military. By the way, my time at prototype was at S1C in Windsor.