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Linhardt's Field Notes: Behind the Looking Glass

Nov. 1, 2004
by Patrick Linhardt The Phone CallA commercial controls guy was on the line. The caretaker at an estate where he did the air conditioning work wanted

by Patrick Linhardt

The Phone Call
A commercial controls guy was on the line. The caretaker at an estate where he did the air conditioning work wanted him to fix their steam system.

Some rooms hadn't heated well for years. There was steam pressure at the boiler, but he just couldn't seem to get this one section as warm as the rest of the house. If he ran the boiler long enough by raising the thermostat, it would get warm, but the rest of the house was like an oven. He sounded quite frustrated, so I agreed to meet him at the job.

This part of town is known for its large houses and fundraising visits by President Bush. Many of the houses were built in the glory years of steam heating, big society shacks with big steam boilers. This place had the longest driveway I've ever had the privilege to drive up. It was at least a half mile of smooth asphalt winding along a wooded ridge and over two gorgeous stone bridges.

When the house finally came into view, I could see my contractor friend and the caretaker looking up at the roof. A huge oak tree had been hit by lightning and crashed a large limb right on an ornate chimney (the kind that twists around and costs more than my house). In addition, the slate roof and copper gutters would also have to be repaired. Ouch!

The Troubleshoot
We went inside and met the lady of the house. To my surprise and delight, she was interested in the operation of her steam system, and even came down to the boiler room with us.

The first thing I like to do is familiarize myself with the system piping. So we all trekked around the basement looking for the end of steam mains, tracing wet and dry returns, and looking around. I was having trouble finding the end of the steam main for the area of the house that wasn't heating properly.

The four of us were standing in a large bath just off the billiard room. I asked the caretaker if there were any rooms left to see. He looked at the customer, who looked back at the caretaker, then looked me up and down, looked at the contractor, and looked back at me.

Curiously, she reached up behind her in the linen closet. I heard a buzzing sound and the caretaker swung open a full length mirror like a door. The contractor commented, "Ten years Ive been working here and you never showed me this."

We stepped through the passageway behind the mirror/door into a vault-like room with a bank safe and cases of liquor, wine, and beer.

I looked up to find the end of steam main I was searching for, and sure enough, there was the problem. This was a twopipe system that used radiator-style thermostatic traps at the end of the steam mains to vent the air over to the dry returns, which then carried the air back to be vented in the boiler room. Unfortunately, someone years ago had removed the trap and capped off the connections to the steam main and dry return.

Why? Who knows. Whatever the reasoning, it was the wrong thing to do. This steam main without a vent was pooling air at its end, thereby blockingthe flow of steam up the risers to the radiators. Steam pushes air ahead of it as it moves through the system. The air from the main had to find its way out through the radiator traps, a much slower process.

The first thing I like to do is familiarize myself with the system piping. So we all trekked around the basement looking for the end of steam mains, tracing wet and dry returns, and looking around.

Consequently, steam reached these radiators only after the radiators in the rest of the house were warm. When the thermostats were satisfied, these radiators hadn't received enough steam to do their job. They never got as much steam as the others, unless the thermostat was turned way up.

The Follow-up
I explained to the crowd in the secret room that a new trap would have to be installed to act as the air vent for that steam main. With air removed from the end of the main, steam would fill the main first, then flow evenly up the risers.

This main would now be vented like the other supply mains, just like it was drawn up 80 years ago. Balance the main venting and there would be balanced heat upstairs.

The lady of the house appreciated that the mystery had been solved. The caretaker cursed his predecessor for not getting this fixed right the first time. The controls contractor was still mad that he wasn't allowed in here the past 10 years, which would have allowed him to solve the problem much sooner.

As for the storm damage, the owner of the estate had the whole roof replaced, all the chimneys re-done, and new copper gutters and downspouts installed.

However, he didnt stop with the outside. The controls contractors company was awarded a contract to update the whole steam system. They then subcontracted out the new boiler installation, but had me specify the new boiler piping's size, pitch, and height.

The contractor also added a boiler feed unit for a nice, steady waterline and peak operating efficiency. Float and thermostatic traps were added at the end of the steam mains to keep the steam from trying to sneak out of the system through the vent pipe of the boiler feed unit. That can cause water hammer in the wet returns and/or a steam bath in the boiler room if overlooked.

Because the caretaker now had time to spare, he went around the house and replaced the guts of every steam trap in the place. Most hadn't seen a pipe wrench since the day they were installed. Now, the steam goes to and stays where its supposed to.

And finally, I was happy when the lady of the house reported that her castle was never more comfortable.

Patrick Linhardt is the sales manager at Aramac Supply in Cincinnati, OH. His newly-released book is Linhardts Field Guide to Steam Heating. To order, visit or call 513/703-5347.