Skip to Content

The Art of Troubleshooting


Sometimes, you just stumble over the answer. I think that the art part comes in recognizing that you got lucky that time. Now you have to figure out why you got lucky.

And then you have to remember because you know this is probably going to happen again.

In the early days of steam heating, they were making it up as they went along. The English tried it first and then left it to the Americans to develop. I suppose the English did this because gravity-hot-water heating was far safer than steam heating, and their decision shows their mechanical maturity and, at the time, common sense.

But before they got to that point, there was this delightful story about an unnamed Englishman who was piping what they thought of as a boiler in those days to what we would someday call a radiator. In between those two components was steel pipe, made strong.

The problem, though, was that the steam wouldn’t travel from the boiler to the radiator. The unnamed Englishman thought there was something wrong with his steel pipe, so he decided to try a pipe made of cast iron instead. This worked, but not because of the different metals; it worked because the cast-iron pipe was poorly made and contained sand holes from the casting process. Those holes allowed the air to escape.

So troubleshooting: Air and steam are both gases, but steam is lighter than air, and where there is air, steam will not go. The steel pipe was solid so the steam just pushed the air down the line like a plunger. Our Englishman didn’t know about radiator air vents because they remained years in the future, so he wasn’t thinking in terms of air.

And now for his troubleshooting epiphany. When steam reached the sand holes in the pipe, it, of course, leaked out, so our Englishman sealed the holes tightly with rags and sat back satisfied. So there.

But now that the air couldn’t escape, the steam stopped moving. Our troubleshooting ancestor scratched his head and considered that it had worked a moment ago? What changed? He removed the rags and to his delight, the steam raced toward the radiator. This led (eventually) to the invention of the automatic air vent.

So we learn that The Art of Troubleshooting involves first paying attention and then asking that key question: What changed?

In 1933, at Imperial Chemical Industries, Ltd. in England scientists were studying the behavior of ethylene and benzaldehyde under high pressure and temperature. They went a bit too far with the experiment and that caused the autoclave to explode, blowing up the lab but, happily, not hurting any of the scientists. When they looked inside what was left of the autoclave, they saw a white, plastic residue. After a time, we came to call this residue polyethylene. It, in turn, would evolve into PEX during the 1960s. How’s that for a happy explosion?

But the scientists had a troubleshooting problem. For three years, they tried to recreate that polyethylene but it was no dice. So they asked that key question: What changed? And then they realized that since all else had failed, they would have to recreate the original experiment. They blew up another autoclave and there it was. It seems it was the introduction of oxygen to the process when the ethylene and benzeldhyde were at high pressure and temperature that acted as the catalyst and made the polyethylene magic happen

When all else fails, you go back to what you know for sure and ask that question: What changed? And then you ask this second question: What can cause that to happen?

You’re on a job and a radiator’s not heating. It heated last week but now it’s cold. Something changed, right? What can cause that? Put together a list. I’d start with these three things:

  1. There’s no water in the radiator.
  2. There’s no flow through the radiator.
  3. There’s air trapped in the radiator.

If there’s not enough pressure in the system to lift water to the top and pressurize it at that high point, there might not be any water in the radiator. The system could be leaking or the automatic feed valve may not be working. Without water, there can be no heat.

If there’s no flow through the radiator, this could be a balance problem. Water may be short-circuiting to another part of the system. What’s changed? Look around. I’ve solved problems by closing a simple gate valve in a bypass that someone else had opened by mistake. Feel your way through the system and think like water. What would you do? Where would you go?

I’ve also seen jobs where something got stuck in the pipe and stopped the flow. I once worked with a contractor who pulled a silver coin out of an elbow. How it got in there will always make me wonder, but I will never forget that this is possible, and I will always have it on my list of things to check.

If there’s air trapped in the radiator, and not enough pressure differential across the radiator to move that air along, then flow will stop. Most troubleshooters go for this one first because it’s the easy one. That’s why I listed it last. Don’t assume that air is always the cause. A flow-balance problem will look exactly like a trapped-air problem. If you open an air vent and nothing but water comes out, that’s not an air problem.

And if it is an air problem, it’s time to wonder where all this air is coming from. What changed? I had this happen in my own house. We have copper-fintube baseboard and our house is on a slab. There are places where the pipe dips into the concrete to clear the front and back doors. We suddenly had all this air that was not there last heating season. Instead of going to the boiler room, I went instead to the tile floor by the front door, which had turned into a radiant floor. That wasn’t part of the design. We had to chop up the floor to get at that pipe and I wasn’t happy with that, but I did feel good about looking in the right place for the cause of the problem.

Always go back to what you know for sure. Ask what changed. Then ask what can cause that. Those questions are at the heart of every troubleshooting call you will ever make. Do these things and you’ll be the hero. 


Leave a comment

Related Posts

Freezing Univentilator Coils

I had written a story for Plumbing & Mechanical a while back about a fella in Canada who sent me this email: "Our problem is that five out of hundreds of univentilator co...

Published on 05/08/2023 3:15 PM by Dan Holohan
Posted in Steam Heating
near boiler piping
Dry Steam Is The Goal

I love all the advances taking place in the world of hydronics, but I’m still seeing plenty of steam systems out there in our older cities, so knowing about dry steam wil...

Published on 03/01/2023 10:29 AM by Dan Holohan
Posted in Steam Heating