Do Pool Heaters Have Pilot Lights? A Deep Dive Into Ignition Systems

Understanding Pool Heater Ignition Systems

Short answer: Some pool heaters do have pilot lights - usually older gas models. But many newer ones use electronic ignition instead.

Ever tried turning on your pool heater only to be met with silence and cold water? It’s like your heater is ghosting you. The culprit could be your ignition system. Knowing how it works can save you time, stress, and money. So let’s break it down and help you figure out exactly what’s going on under the hood of your pool heater.

What is a Pilot Light in a Pool Heater?

If you run a gas pool heater, there’s a good chance it uses a pilot light. That’s the tiny flame that stays on quietly, waiting to spark the main burner to life. It might look small, but it plays a big role in warming up your entire pool.

A pilot light is kind of like a watchful lifeguard. It doesn’t jump into action until it’s needed - but when it is, it gets the job done fast. Older heaters rely on these small flames, while newer models usually go with more modern, energy-smart options.

How a Pilot Light Works

Here’s how it all kicks off. Your thermostat senses the water temperature dropped below your set point. It tells the gas valve to open, and that’s when the pilot flame lights the main burner.

The main burner heats the water, then the system shuts off once the right temperature is reached. It’s a simple chain reaction - but if that pilot light goes out, nothing happens. You’re stuck with cold water and a big question mark.

Types of Gas Pool Heater Ignition Systems

Not all gas heaters are built the same. Some have that old-school, always-on pilot flame. Others use a more efficient system that only lights when the heater is running.

Your heater will either use a millivolt ignition or an electronic one. The difference affects how you light it, how often you need to maintain it, and what to check when things go wrong.

Millivolt vs. Electronic Ignition

Let’s talk ignition types. Most gas heaters fall into one of two camps: millivolt ignition or electronic ignition. Here’s what each one means for you as a pool owner.

Millivolt Ignition (Constant Pilot)

This is the classic system found in many older heaters. The pilot light is always on. When the flame is lit, it heats up a little device called a thermocouple. That device creates a small electric current - just enough to keep the gas valve open and get the burner going.

Pros:

• No need for electricity

• Easy to understand and use

Cons:

• Always burning gas, even when not heating

• Can blow out in the wind or due to dirt buildup

• Needs manual relighting

Let’s say you go out of town for a few days. While you’re gone, a strong wind blows through your backyard and poof - out goes the flame. Now the heater’s dead silent when you get back. Annoying? Definitely.

Electronic Ignition (On-Demand Pilot)

This system only lights the pilot flame when it’s actually needed. A small electric spark ignites the flame just before the burner kicks in. Once your pool hits the right temp, the system shuts off completely.

Pros:

• Saves energy

• Safer since there's no constantly burning flame

• Often restarts automatically if something goes wrong

Cons:

• Needs a power connection

• Can be more expensive to fix

Many modern pool heaters use electronic ignition. They're great if you're looking for efficiency, especially if you use your pool year-round.

Common Pilot Light Issues and Troubleshooting

Even the best systems can hit a snag. When the flame goes out or won’t start at all, your heater stops working. Here are the most common problems pool owners run into - and what you can do about them.

Pilot Light Won’t Ignite

If your flame just won’t light, here’s what might be going on:

• The pilot tube could be clogged with dirt or bugs

• You might have a faulty gas valve

• No gas is reaching the heater

• The ignition switch or control board could be broken

Start simple. Look for dirt or webs near the pilot assembly. A quick clean with a soft brush and canned air can sometimes fix it in minutes.

Pilot Light Keeps Going Out

You finally get it lit, but it goes out again and again. That’s frustrating. Here’s what might be behind it:

• A worn-out thermocouple

• A draft blowing the flame out

• Rust or soot blocking the gas flow

Picture this: it’s a breezy day, and your heater is on the patio. A little gust is all it takes to snuff that flame. If it happens often, consider adding a wind guard or moving the heater to a more protected spot.

Potential Causes for Pilot Light Problems

Let’s break down what causes most flame failures:

• Dirt or grime blocking the flame

• Loose or corroded wiring

• Weak gas pressure

• Worn-out thermocouple or pilot generator

• Defective control valve

Many of these problems build up over time. Cleaning the pilot area every few months and checking for wear can help avoid a full breakdown later.

When to Seek Professional Assistance

Sometimes, DIY just doesn’t cut it. If your heater still won’t work after cleaning and checking the basics, don’t risk it. Gas and electricity are no joke.

Call in a licensed pool heater technician if:

• You smell gas

• You suspect a broken gas valve

• The pilot light won’t stay on despite several tries

• You’re not sure what to check next

A pro can spot the issue quickly and make sure your system is safe. It's always better to get help than to guess and make the problem worse.