Joe hates electronics. “Gol’dern new stuff. How can you fix it if you can’t see how it works?”

Joe Jr., a generation younger, loves electronics. “Heck, Dad, the self-diagnostics tell you what’s wrong, so there’s nothing to figure out. But really, Dad, something else is usually the problem, like the wiring. I’m just the kid around here, but if you want to know how electronics work … ”

Frankly, Joe doesn’t want Joe Jr. to explain how electronics work. He just wants the new stuff to go away. Then he can get back to the days when he could spend an afternoon fiddling with things until he got all the pieces apart and back together again.

It looks like Joe isn’t going to get his wish. Electronics are here to stay, even in the not-always-so-progressive plumbing and heating biz.

A few weeks ago, I attended a tankless water heater class. I was astounded. Kyle, the manufacturer’s rep and trainer, said, “If you’re here to learn how to install a water heater, you might as well go home. This isn’t a water heater - it’s a computer.”

I looked around the room at 39 pairs of muddy plumber boots, and thought, hmm, there’s going to be a stampede for the door.

But everyone stayed. Maybe the promise of food kept them in their seats. Maybe they were just tired at the end of a long day. Or perhaps the industry is changing.

Everything’s Changed

The world has changed. Cars are electronic. Appliances are electronic. And yes, the plumbing and heating business is slowly becoming electronic. Like with the tankless water heater, the manufacturers aren’t giving us any choice. As rep Kyle said, “If your idea of a water heater is still the old-fashioned ‘barrel on a campfire,’ this new stuff may not be for you.” 

As I was listening to Kyle, I had a chance to think, “Well, what are electronics, anyway? Just how are electronics so different from ‘not-electronics?’”

The difference is what’s done with the electricity. With old-fashioned electricity, you start with a particular voltage, say 24 volts, and wave form, say alternating current (AC), and keep that. All you do to control the circuit is turn the electricity on or off with a switch.

In electronics, both can be changed. An amplifier circuit changes voltage to adjust volume. In a variable-speed DC motor, the waveform is changed.

But these differences aren’t what matters to us practical folks. We want to know what it does. What’s it good for?

Electronics are useful because there are no moving parts to maintain. There’s not much heat to dissipate. They don’t take up much space. And even though electronic gizmos can be pricey, compared to electro-mechanical alternatives, they are inexpensive to manufacture.

Electronics let us do things that would otherwise be impossible. The “computer” controls of the tankless water heater can bring on just enough flame to add just enough Btus to keep the water at set point. With a conventional water heater, we have one size flame, and it can be either on or off. Temperature swing (called differential) is probably an uncomfortable 15 degrees.

But let’s return to Joe’s predicament. He’s let electronics remain a mystery even though they’ve been around most of his life. It’s been half a century since words such as “solid state” and “transistor” (remember transistor radios?) appeared. And there are other words that we use all the time without thinking about what they mean: LED, DIP switch, thermistor, semiconductor and microprocessor.


Let’s just go over what these words mean to show how un-mysterious electronics is.

Solid state, as in solid-state circuit, simply means no moving parts. It’s in a state of being solid.

A semiconductor is a material that conducts electricity under certain conditions. Back in elementary science we learned that metals conduct electricity and rubber and glass don’t. Semiconductors are choosy about when and how they conduct.

Silicon is one of the materials that’s best for making semiconductors. Thus Silicon Valley is the home of big semiconductor businesses.

When you look at an electronic “board,” or printed circuit board, there are lots of bead-like pieces all over it. As a group there are called semiconductors. Individually, they are resistors, transistors, thermistors, diodes, SRCs, and triacs. Each has a special function. On the board, they are wired together into circuits, similar to a circuit that we’d make to wire a thermostat, zone valve and transformer. Of course electronic circuits are tiny. That’s how we get to words like “microelectronics” and “microprocessor.” 

Let’s take the mystery out of these little critters and look at what they do:

An electronic resistor looks like a bead with colored rings on it. Those colors are code for the amount of resistance each has. Like in old-fashioned electricity, a resistor “resists” the flow of electricity to cause desired things to happen.

A thermistor is a resistor whose resistance varies as the temperature changes. It can communicate temperature by changing the resistance it reports.

A transistor is a three-legged resistor that can use low voltage to vary power into higher voltage circuits.

A diode looks like a resistor but has only one colored ring. It allows electricity to flow only one direction.

A light-emitting diode (LED) creates light as the electricity flows through it.

A DIP switch is often found in electronics from the 1980s and 1990s. DIP stands for “dual in-line package.” That means there’s a line of tiny two-position switches. The switch positions you select help tell the microprocessor what it’s supposed to do.

SRCs and triacs are electronic relays.

When the printed circuit board is connected to other devices, it becomes a module or a microprocessor.

The devices that bring in information, or data, are called inputs. In the heating business, typical inputs are temperature from a thermistor and flame current from a flame sensor.

The module expects or “looks for” certain kinds of information from the inputs. When it receives or “sees” the correct information, it creates electrical output

Output allows other devices to be turned on or off. Typical output in the heating business would be to open a fuel valve once the module has “proven” that there’s a need for heat and that all of the safety conditions have been met.

The module turns input into output by using mathematical formulas called algorithms. The result is called logic.

Because a module or microprocessor seems mysterious, it often gets blamed when there’s a problem. Manufacturers say tens of thousands are replaced needlessly every year.

The module is just the “thinker.” It’s completely dependent upon having good input. That means that all the devices giving it information need to be working correctly. It’s also dependent upon the output devices being functional.

But the most frequent problem a module gets blamed for is in the wiring bringing information into it or out from it. Do you know the word intermittent? That usually means the wiring looks solid, but somewhere a connection is loose.

No matter how simple we make the subject of electronics, Joe’s still right. He darn well doesn’t have to learn anything “new,” even though it’s been around more than 50 years. Joe thinks that with all these changes, he just might hang up this business after all these years. He thinks maybe he’ll just stay home and watch his new giant flat screen TV. By golly, no one can make him use electronics!