The art of system renovation

THE PHONE CALL: One of my regular customers told me about a conversation he recently had with an arts council administrator who was about to take over paying the energy bill for his building and was starting to worry. The administrator was complaining of too much heat, thinking that some repairs would be better done over the summer and wondering if part of the building could be removed from the steam

THE PHONE CALL: One of my regular customers told me about a conversation he recently had with an arts council administrator who was about to take over paying the energy bill for his building and was starting to worry. The administrator was complaining of too much heat, thinking that some repairs would be better done over the summer and wondering if part of the building could be removed from the steam system.

I said that it sounded like a long list of concerns, and my customer asked if I was interested, and I told him yes.

We drove up together since the job is about an hour away in a quaint college town, complete with a cobblestone main street. It's out in the country, past farms, fields and barnyard odors.

Eventually we pulled up to a threestory, red-brick building framed by large oaks that stretched the better part of a block. It was built in the late 1800s as a women's college, away from the main campus. The arts council was taking over the majority of it to use as exhibition-and studio spaces. A historical society was taking over the rest and would install its own HVAC system.

The troubleshoot
It was a mild spring morning but already summertime hot in the foyer as we walked past a very warm cast-iron radiator. We met the administrator and his assistant in the boardroom with a set of plans and another hot radiator. I noticed that both of them were wearing light clothing for that time of year.

I inquired about the location of the building's thermostat and was met with blank stares. Neither had any idea that they could control the amount of heat in the building.

At that time, the university owned and maintained the property, which has its own steam boilers. The college campus has a district steam heating system. Consequently, the maintenance personnel had a "steam all the time" mentality. The boilers were set to run 24/7, keeping steam pressure at the header at 3 PSI, regardless of the need. That way, it eliminated those nuisance no-heat calls. No wonder sweat was forming on my forehead.

I suggested a cycle-rate control for the overheating. It would run the boilers on varying on-off cycles in relation to the varying outdoor temperatures. On a mild spring morning, it would have steam on for 15 minutes out of an hour, then off for 45 minutes. Not on for the whole 60 minutes. This saves energy and improves comfort. The administrator began to pay attention.

Since the only problem with a cyclerate control is that the system has to operate properly, I said we should look around at the piping. Unfortunately, it quickly became clear that this system was suffering from neglect. The boilers were less than five years old, but the pipes, traps and return system hadn't been touched in five decades.

One area of concern led to another area that needed repair. The most pressing of the problems was leaking underground return pipes. Leaks in a steam system cause new water to be added to the boiler. This fresh water has minerals and oxygen that can cause problems.

It's a deadly one-two punch. Minerals come out of solution and attach themselves to the inside of the hot boiler below the waterline. Oxygen comes out of solution to erode the metal on the inside of the boiler above the waterline. Those five-year-old boilers weren't going to last long with leaking underground lines.

By lunchtime, it was clear that major renovations were required. Underground piping needed to be eliminated and the returns run to condensate transfer pumps in low points of the building. The removal of part of the building from the steam system would require re-piping the 6-in. supply main from the header to a new location in the system.

I was concerned the cost of all these changes would be more than the nonprofit organization could bear. The contractor and I decided to give the administrators a "budget" number to test the financial footing. It surprised us when they told him to proceed.

The follow-up
The piping crew sweated there for weeks that summer replacing traps and piping, while adding the pumps. I returned a few times to look over the progress and suggest changes as the walls, ceilings and floors opened up to reveal new surprises, good and bad.

The path of the steam was rerouted through the new 6-in. main to the distribution piping and radiators. The path of the air out of the supply piping and radiators was rerouted to the vents on the condensate transfer units. The path of the water back to the boiler feed unit was then rerouted through the pumps on the condensate transfer units.

When fall came, with students back on campus and a chill in the air, it was time to fine tune the renovated system. Fortunately, we had spent enough time studying the system. All it needed was a tweak to the cycle-rate control.

The system performed as advertised, with steam, air and water smoothly moving along their paths. All the while, the cycle-rate control was keeping the building from overheating and the gas bill from being too much of a burden. The administrator was happy with the results, although he now dressed in a sweater instead of short sleeves.

The contractor was glad that he had kept his crew busy during the summer, which isn't always easy to do. I was glad that we could save a steam system, and that it worked as promised after so many changes.

TAGS: Plumbing