Sherlocks go to the top to solve mystery of the pipes

Ever longed to trade wingtips for gumshoes, stock reports for stakeouts, computer models for the Maltese Falcon? Working on an old house is one way to give your investigative aspirations a workout.

There are a lot of secrets hiding in the walls, crawl spaces, attics and basements of older dwellings. Sometimes they're given up readily, but other times you have to do legwork.


We've mentioned before that plumbing can be a sort of old-house Bermuda Triangle, where odd things happen to pipes and connections are not always what they seem.

Randy and his colleague, Gene, have spent about a week now moving radiators and radiator pipes in an addition/kitchen remodeling project. When layouts were changed to open up the space in this eclectic 150-year-old house, some of the old pipes ended up in the middle of the floor.


One set of pipes, feeding a radiator on the second floor, ended up in the way on both floors; the radiator was making way for a doorway. They cut the pipes and removed the radiator, and there the mystery began . . . because the pipes continued up the old wall and through the ceiling, through the third floor and out through the roof.

Where were they going? Were they connected to some other radiator above, or some other part of the system?

To figure out what to do, the carpenters turned detective.

The first task was to determine what kind of heating system the house had. There are two predominant types of hot-water (boiler) systems. The so-called "open" system usually had a tank at a location higher than the highest radiator -- often at the ceiling of a bathroom or in the attic. The system operated at fairly low pressure, and the tank had a pipe that went out through the roof to expel any excess water. Usually the old tanks had a sightglass to check the water level: If you could see water in the sightglass, the system was full.

The other type of system, the "closed" system, operated at a higher pressure. Water circulated through the system, often with the help of a circulating pump, and returned to the boiler to be reheated. Usually such systems had an expansion tank next to the boiler to collect excess water.

Over the years both types of systems sometimes got modifications that made them work differently. A lot of people with open systems converted to a closed system when they replaced an old low-pressure boiler with a "modern" higher-pressure one. Unless unneeded pipes were in the way, they were simply capped and left.

In the current case, there were strong clues to indicate the system was closed. The boiler has a circulating pump and a pressure gauge; it also has a pressure-relief valve set at a typical closed-system pressure of 30 pounds per square inch. An open system wouldn't need a pressure-relief valve, the pipe to the roof would relieve the pressure.

But despite the closed-system clues, there were those pipes running out through the roof. And if the system turned out to be an open one, the pipes at the second-floor level would have to be reconnected above and below, to make the "overflow" system work -- at a cost of a couple hundred dollars in copper and labor.


The eccentric design of the house -- a blend of Queen Anne and Craftsman styles -- deepened the mystery. A series of gables with peaked roofs and other places with flat roofs (all in slippery slate) made the pipes hard to trace.

The old-fashioned way to determine if a pipe is open or capped -- and this is not an especially pretty thought -- is to blow on it. (Well, in old houses, sometimes low-tech solutions are the most appropriate.) So the sleuths trekked back to the second floor, where the pipes were cut off, and blew into them. They seemed to be capped. But where? And where did they stop?

Because of the roof lines, there was no place to stand outside and trace the pipes once they left the third-floor ceiling. Randy found a window on the third floor that looked out on the gable the pipes pierced, but the vantage point wasn't quite high


They had been assuming, because of all the peaks, that the third floor was the top of the house. So what was next? Hire a helicopter?

Then they discovered the attic hatch. It was the first real breakthrough in the case -- and what's more, the attic had a window right over the gable where the pipes came out. When they looked out, they discovered the pipes ran back into the house -- right about where the attic started.


They dug into the rock wool insulation below their feet and found pipes. To make sure they were the right pipes, Gene tapped on them in the attic while Randy went back to the second floor to feel the pipes there. Yes, they were vibrating.

Back in the attic, they traced the pipes through the insulation to the base of the chimney. They were capped there.

It seems clear that at some point there was an expansion tank with a sightglass mounted to the chimney. The mystery was solved. This was a former open system converted to a closed system. The pipes that were cut would not need to be reconnected, resulting in a big saving.

Randy and Gene are standing by in case Scotland Yard calls. But the lesson is, when dealing with the intricacies of an old house, you have to be persistent to get at the truth. You can't make assumptions based on a few clues; you have to turn bloodhound and track the mystery all the way to the top.

If you have questions, tips or experiences to share about working on houses, write c/o HOME WORK, The Sun, 501 N. Calvert St. Baltimore, 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.