No, the photo is not what we found at the job without an expansion tank, because we visited the job site recently and still didn’t find it. The homeowner came back from her extended Florida vacation and was willing to let us explore more of the house. On a rainy day, I arrived early for a change and got a better look at the house as I came up the long driveway.
It didn’t appear to be added onto like I originally thought and there wasn’t much attic above the Mansard roof. The contractor arrived and we went to meet the homeowner. I asked her when the house was built. She replied in 1963, with the boiler room specifically not located below the house. Seems the guy building it back then had a boiler explosion in the basement of his previous house.
With that information, the crawl spaces we previously explored made more sense. The whole living space of the house was over a series of crawl spaces, since the guy (or his wife) building it were freaked out by the accident in the last basement. No basement, no problems. Funny things motivate people to do funny things.
Back to the Crawl
We left the kitchen where we were talking to walk to an access to a crawl space from inside the house. The boiler feeds three air handlers that have hot water coils. The first day we found one of them in a crawl space very close to the boiler room. We dropped in to investigate. This day we found the second air handler in a crawl space towards the opposite side of the house, fed by an un-insulated 1-1/4” copper pipe. It was the 60’s, they did things differently back then.
No tank found there, so we headed in the direction of the boiler room, crawling on all fours at first, then on our bellies to get under ductwork as we approached the other side of the wall that stopped our last exploration. We eventually identified it by the number and size of the pipes. Sure enough, there was the suspected ¾” copper pipe. Like before, it was much cooler to the touch than the other pipes.
There were the two pipes going to the air handler we had just found and two pipes going to the third air handler, which I learned—while flat on my stomach—was on the second floor. The suspect ¾” pipe and the third air handler’s two pipes disappeared into a chase that ran up to the second floor. We looked through the rest of the crawl space to no avail before getting out.
The contractor and homeowner were off to the second floor before I had knocked the dust off my clothes. I caught up to them and peeked into a utility closet on the second floor. There were the two pipes re-appearing out of the attic and connected to the air handler. The suspect ¾” pipe was nowhere to be found.
Around to the Bulkhead
The homeowner then told us about another access to under the house, which might lead to other crawl spaces. She said there wasn’t an “attic” and wanted us to go back outside in the rain to a “bulkhead”, insisting we take a screwdriver. We are both polite men that don’t want to upset a customer, so out we went.
On the opposite side of the house from the boiler room was set of doors leading below grade, like what usually is used for an outside basement entrance. But at this house, they opened to a crawl space access, just big enough for an air handler to get in. A wooden cover was already loose, so no screwdriver was required. Once in, we realized it connected to the space with the second air handler. Nothing new to see there, and no expansion tank in sight.
As we walked back around the house, we decided that there must be an attic with an attic hatch somewhere on the second floor because there is ductwork feeding registers on the ceiling. Unfortunately, we were out of time since the homeowner informed us she had to leave for an appointment. The search was called off until the crew comes to install the new boilers. Maybe next time…
A Chemical Shot Feeder?
Some of you might recognize the item in the photo. The Kid (who I’m training to take my job if you’re a first time reader) didn’t have a clue. Frankly, it took me a little while to grasp what was going on. That’s the beauty of hot water and steam heating. You never know what you’re going to see next.
Coincidently, this house also was heated with hot water coils in air handlers. Just two in this case since it is a much smaller place. Also, the boiler wasn’t in the basement. In fact it wasn’t a boiler at all, but a swimming pool heater that was sitting outside along the driveway. The supply line split to a pipe going into the basement and to a pipe going up the outside wall and then into the second floor.
The homeowner was also a single woman. To reach her second floor air handler, we walked upright through her enormous closet to find this chemical shot feeder attached above the coil, with a gauge glass set added to the piping. It did take me a minute or two to understand that this was the expansion tank for the system. Not your conventional setup.
Since the pool heater/boiler was outside, the system had a glycol mix circulating instead of straight water. To make it easy to get the glycol mix into the piping, it is poured into the top of the shot feeder where the chemical usually goes. The gauge glass was there to indicate when more glycol mix was required to be added.
When the gauge glass was half full, the air cushion in the shot feeder was enough to accept the expansion of the glycol/water mix as it warmed up. The system doesn’t have much water/glycol volume, so that cushion of air doesn’t need to be very big.
Its location above all the radiation was like the open expansion tanks for the old systems, but completely different because it was a closed system. It was the first time in 38 years of poking around basements and attics that I came across this setup. Credit to the guy who came up with it or maybe it’s something that’s done in your area. Let me know if you’ve seen this before.
Andy B, a plumber in NYC, has an idea of what we might find in the attic of the job without an expansion tank. I’ll let you know his thoughts and what, if anything, we eventually find. Next month I’ll switch to something about steam heating.
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.