by Patrick Linhardt
The service manager called during the holidays sounding nervous and excited. His customers were experiencing uneven heat in the home, and he was worried that the number of main air vents in their system could be the culprit.
At the same time, the service manager was thrilled to have found an old Broomell vapor system, the same kind I had raved about in a recent seminar. He asked if I wanted to give it a look. I leapt from my chair.
When we came in the home's kitchen door, I immediately noticed the smell of baking coming from an oven as big as the front end of a 1958 Buick.
A cherub-faced boy appeared and asked if we wanted to see his train set. I love toy trains, especially at Christmas.
We followed him to the living room where he started up his express train. It went chugging around the Christmas tree, puffing smoke rings as it zoomed past a miniature freight station, a water tower, and then through a tunnel.
We thanked him for letting us see his fine train set and stepped into the foyer to look at a radiator. The service manager showed me the radiator handvalve with the wooden lever handle and " Vapor" cast in the body. He pointed out the vapor device on the return side.
Sure enough, it had the brand name "Broomell" on it. The boy was curious about what we were doing and joined us. I commented that this was my favorite type of steam system.
Because he loved steam engines best, he wanted to know if the steam system in his house was like a train steam engine. He also wanted to know if it ran on coal and had a steam whistle.
I told him that we might be able to answer some of his questions if we went to the basement. I've seen a lot of strange things in my twenty years of looking at old piping, and heck, we might even find a whistle on the boiler.
I explained that both the steam engine and the steam boiler work with steam pressure. The engine needs a very high pressure to make the heavy train cars move, while the boiler only needs a very low pressure to make the house warm. In fact, that's one reason I like this type so much.
I stretched the truth a little and told him that the Broomell system had a whistle on it , and if it was still installed, I'd show him.
In fact, to keep the pressure extremely low on the system, the Broomell receiver has a built-in relief valve. A copper float moves up and down in the body of the receiver in relation to the pressure in the boiler, while the gauge glass shows that pressure in ounces.
A rise in pressure pushes the float up, while a chain and pulley system would close the coal-fired boiler's draft doors, decreasing the fire.
If the pressure is still too high, the float pushes the relief valve open. I told him that this steam release might be like a steam whistle going off. The boy raced down the steps ahead of us to the basement.
I was quite surprised at what I found down there. The service manager was correct: this system had too many vents. By the time I traced out the piping, I counted 10.
There were five at the end of the steam mains and five at the end of the dry returns before they dropped into a wet return. This wasn't that large of a house, maybe 14 or 15 radiators at the most. That's 1.5 radiators per main air vent.
In addition, this didn't look like a Broomell system at all. Broomells were designed for one vent releasing the air into the chimney through the receiver, and typically no wet return. I was now the curious one.
We wandered back to the boiler room where our junior train engineer was still looking for a whistle. I explained that the Broomell receiver must have been removed some time ago.
He didn't stay disappointed too long, and asked where in the boiler one would shovel in the coal. I told him that few modern boilers operate on coal anymore, just as few train engines operate on coal these days.
The little rascal had helped me realize that the system must have experienced a radical transformation in the basement when the original coal boiler was replaced many years ago. Nothing had changed upstairs in the radiators, but someone had really complicated the piping system downstairs.
From the standpoint of steam distribution (steam up), the five steam mains had plenty of size to limit steam pressure drop. However, the way they were piped required ten air vents.
Most residential systems have one main along the front of the house and one along the back. When it comes to air removal (air out), vapor systems need more venting capacity than pressure systems.
However, 10 vents are far too many for this size system. In addition, replacing them would be quite an expense. From the standpoint of condensate return (water back), a dry return is much less likely than a wet return to ever clog and slow the return of condensate, which can cause boiler flooding. This modified design had me thinking, and not about visions of sugarplums.
I enjoyed my visit with the curious boy. The cookies were hot out of the oven when we got back upstairs. We shared a few while he ran the train and blew the electronic whistle as it passed the highway crossing.
Regarding the renovation of their system, the homeowners didn't want to make any changes because of the expense and their uncertainty of how long they were going to live in the home.
As it turns out, it wasn't too long. In the spring, I received a call from another contractor inquiring about converting a steam system to hot water. It was the same house. Although I'm not a big fan of abandoning steam systems, this one needed too much of an extreme makeover.
The new contractor's solution was to change the basement piping to reverse return and pipe in the condensing hot water boiler as primary-secondary. He also added air vents to the radiation, but left the handvalves and vapor devices installed. As a result, the new customer's comfort issues were resolved.
However, with the appearance of steam on the top floor and a hot water system in the basement, I wonder how confused the next contractor will be.
Patrick Linhardt is the sales manager at Aramac Supply in Cincinnati, OH. He often lends his sleuthing skills and technical expertise to local contractors in need. His newly-released book is Linhardt's Field Guide to Steam Heating. To order, visit steamupairoutwaterback.com or call 513/703-5347.