The Case of the Belching Boiler

A friend had called me to say that his building’s boiler was acting strangely and the building was losing heat and hot water. Could I come over and take a look? It being Saturday evening, naturally, I had nothing going on, so I strolled over and met my friend in his basement.

It wasn’t the boiler itself that was acting strangely, but rather the condensate receiver that fed it. The receiver is part of a system that includes a condensate pump, which is used to pump the condensate (water) from the radiators in the apartments. The condensate receiver works a lot like a toilet in reverse. As it becomes full, a float inside activates a pump and the water is pushed back into the boiler. At the discharge side of the pump, a one-way check valve prevents the water from backing out of the boiler when steam pressure starts to build.

My friend showed me the malfunctioning boiler. After it had run for a few minutes, all of a sudden water would come gushing out of the receiver’s air vent in a violent torrent. Spooked, the building residents had called in a contractor to assess the situation. What they needed, the contractor pronounced confidently, was a new, larger condensate receiver, to the tune of about $7,000. Needless to say, this was in the middle of the heating season, and my friend was under pressure to solve the problem ASAP. Like, immediately.

Nonetheless, he blanched at the prospect of spending seven grand on the boiler if he could avoid it, and decided a second opinion was needed – which is how I entered the picture. Once onsite, I inspected the boiler, the receiver, and some other equipment. I noticed nothing untoward, although it looked like some of the condensate pipe near the receiver was in the process of being replaced, probably because it had been leaking.

I asked him to show me the problem again. He turned on the boiler. We easily recreated the aforementioned torrent, and it was enough to frighten anyone into spending seven grand, or even more, simply to stop the gusher and bring back the heat and hot water.

A Vision Appears

There was just one problem – the contractor’s recommendation was absurd on its face. Yes, the receiver was on the small side, but it was handling only a small fraction of the condensate in the building. And it had operated without incident for the previous two or three years.

Something had changed, but I couldn’t figure out what. I paced the basement fruitlessly for a while until it became clear the answer was not going to come to me right away. As I was leaving, I told my friend to do nothing until I had had some more time to think.

When I arrived home, I retired to the smallest room, which is where I often do some of my best thinking. As I sat in contemplation, I slipped into something of a dreamlike state. Suddenly, a vision appeared in my mind and I knew exactly what had happened. I raced back to my friend’s building with the news, feeling a bit like Sherlock Holmes.

The problem was indeed in the condensate receiver, but not in the way the contractor imagined. As I said, the receiver works a lot like a toilet in reverse. At the discharge side of the pump, a one-way check valve prevents water from backing out of the boiler when steam pressure starts to build. It turned out that, during the condensate pipe replacement work, someone had inadvertently removed the existing check valve and neglected to reinstall it. Not surprising, really, considering what a tiny part it was, and that its function was probably unknown to the people performing the pipe work.

It’s also quite possible the contractor who recommended the unnecessary new/larger receiver sincerely believed he was making the right call. Nonetheless, the result probably would have been that, for $7,000, he would have installed the new receiver, complete with a new check valve, and the problem would have been solved, with everyone thinking that the “undersized” receiver was the culprit. No one would ever have known the difference.

Sure enough, when a check valve was re-installed, the problem was solved. And it didn’t cost seven grand. Elementary, my dear board member!