Patrick Linhardt
The mystery expansion tank is discovered at last.

Eureka!

June 21, 2022
Once you find something in an unusual place, you start wondering why it was installed there.

[Editor's note: this column finally solves a mystery that began back in Pat's January 2022 column.]

It was a beautiful late spring morning. I was driving to the job without an expansion tank, or more accurately, the job where we hadn’t found one yet, despite two other trips and lots of crawling around under the house. Today the mystery would be solved, at least I thought so.

We were scheduled to have access to the attic, since the new boilers finally were built, shipped and delivered. They were going to be installed in the partial basement along with a new expansion tank. We suspected the attic because we found three pipes leaving the crawl space to go up to an air handler in the attic. An odd number of pipes is odd in the hydronic world.

Move to Electric

I was in a great mood. The next day I was going to drive to Oak Park, New York, near Buffalo to look at an electric vehicle. I had been urging my company to start buying electric vehicles as our gas vehicles come up for replacement. This idea was not met with much enthusiasm at first, but I found out later that a certain board member with a lot of influence convinced the rest of the board to at least buy one as an experiment.

The previous Friday, our CFO found my cubicle and informed me that I was going to be the guinea pig to have the first electric car in the company, and oh by the way, that I was in charge of selection and purchase. Luckily I had plenty of time for this project.

It was a slow day for a heating guy in the heat of the cooling season. I scheduled a test drive of one of the electric vehicles that I hadn’t driven yet for that afternoon, then jumped on the internet to see what the world offered.

The boilers on this job took about four months to get in. Most electric vehicles are six to nine months out from time of order, which is a long time to wait to begin an experiment. To get started in a timely manner, I went to a reputable used car website. About three to four pages in, I found a car that fit my specifications with only 2,750 miles in Oak Park, about a six-and-a-half-hour drive from Cincinnati.

It was the brand/type I wanted, but was never able to arrange a test drive with our normal car dealer. Fortunately, a different local dealer had mysteriously received four new cars like it one morning the next week, so I scheduled a test drive. I picked up my wife on the way. I wanted to get her opinion, since she has opinions about everything. It’s just her nature. She keeps me from making bad decisions.

There were three left when we got there. We took a blue one out on a test drive, with our six-foot nine-inch salesman comfortably seated in the backseat. There was some chatter on the internet about this model being a little cramped, but we sensed just the opposite. We loved it, but none of the three on the lot had the extended battery option that I wanted. They also had a $10,000 dealer bump to the MSRP. Yikes!

The car on the internet was looking like my best option, but if I was going to get that one, the CFO insisted that I drive it before buying it. My wife was game for a little adventure, so we planned on leaving that Friday and make a weekend of it. If it was everything the web said, she would drive the old car back while I drove the new one.

The Torpedo

I was thinking of all this while we were standing in the closet with the attic hatch. The homeowner was insisting that there wasn’t anything up there, while also saying that she had never been up there herself. Anyway, the contractor got the hatch open and climbed up. At first, he didn’t recognize it, but then had a eureka moment.

There it was, hanging from the roof trusses, uncharacteristically wrapped in un-faced fiberglass insulation, which made sense with the open to outside attic vent at one end. The contractor is a Navy veteran, so he described it as a torpedo. The homeowner was expecting something the shape of a basketball. We’re not sure where she got that idea. We were just so happy to finally find the damn thing.

Once you find something in an unusual place, you start wondering why it was installed there. I usually begin with history. The homeowner said the house was built in 1952, or so. This is a nice house in a very nice neighborhood, so I suspect that the installing contractor sent an experienced crew for the install.

If the guy laying out the location of the components had 30 years in the trade, then his experience goes all the way back to the 1920’s and gravity circulation, when the expansion tank was in the attic above all the radiation. Just a theory, because we’ll never know.

Since the contractor decided to leave it in place, somebody, seventy years from now, is going to be looking at that tank and wondering why it was ever  there in the first place. Why have 60 gallons of water exposed to freezing temperatures at the top of the house? What if it ruptures and floods the bedroom below?

Heading-Off Future Problems

After we found it, we went back to the boiler room to figure out the best way to disconnect it. We found the ¾” line coming off the supply header of the existing system piping. He was going to have the install crew cap it off on the system side and leave it open on the tank side. The homeowner was pleased to have the potential problems eliminated.

The new tank would be connected to the bottom of the air separator with the fill line like we do nowadays for better air control. That keeps the point of no pressure change and the pressure reducing valve in the same place on the suction side of the system or zone pumps on the supply side. Hopefully, seventy years from now, that will still be the best way to lay out the location of the components.

The next day in Oak Park, the Ford Mustang Mach-E was everything it was supposed to be and more. The only thing my wife didn’t like was the fragrance that the detail guy used. It’s always something…

Patrick Linhardt is a thirty-seven-year veteran of the wholesale side of the hydronic industry who has been designing and troubleshooting steam and hot water heating systems, pumps and controls on an almost daily basis. An educator and author, he is currently Hydronic Manager at the Corken Steel Products Co.

About the Author

Patrick Linhardt

Patrick Linhardt is a thirty-seven-year veteran of the wholesale side of the hydronic industry who has been designing and troubleshooting steam and hot water heating systems, pumps and controls on an almost daily basis. An educator and author, he is currently Hydronic Manager at the Corken Steel Products Co.

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