Common Pool Heater Issues (And What to Do About Them)

A pool heater can be your best friend when it comes to extending your swim season or enjoying a refreshing dip in warm water all year round. But what happens when your trusty pool heater starts acting up? If you’ve found yourself Googling “pool heater not working,” you’re not alone. Many pool owners encounter common issues, but the good news is that these problems are fixable.

This guide will walk you through the most common pool heater problems and what you can do to get your heater back up and running. Whether you’re dealing with a heater that won’t turn on, keeps shutting off, or just won’t warm your pool to that perfect temperature, we’ve got you covered. 

Pool Heater Not Working? (Here’s How to Fix It)

1. My Pool Heater Keeps Shutting Off

If your pool heater keeps shutting off unexpectedly, it can be frustrating—especially when all you want is a warm pool. This issue can be caused by several factors:

Check the Flow Rate

Pool heaters generally require a specific flow rate to keep running. If there’s not enough water flowing through the system, the heater may shut off as a safety precaution. Make sure your pool pump is working properly and that the filters aren’t clogged. Always turn off the heater and pump before inspecting plumbing or internal components.

Inspect the Pressure Switch

A malfunctioning pressure switch, which monitors the water pressure in your heater, can cause it to shut off unnecessarily. If you’re comfortable with tools, test the pressure switch with a multimeter to ensure it’s functioning correctly. If not, consulting a technician might be a better choice.

Look for Overheating

Overheating might cause the heater to shut off to prevent damage. Check for proper ventilation around the heater and clean any debris in its vents to ensure air can flow freely.

Fixes to Try:

• Backwash the pool filter to improve flow.
• Check pump speed settings if you have a variable-speed pump.
• Confirm that all valves directing water to the heater are open.

If these solutions don’t resolve the issue, it could be a more complex problem requiring a technician’s help.

2. My Pool Heater Isn’t Turning On

Your pool heater not working properly is one thing. But nothing is more disappointing than a pool heater that won’t turn on at all. Here’s what to check:

Examine the Power Supply

Start with the basics—ensure the heater is plugged in and power is reaching the unit. Double-check your circuit breaker to ensure it hasn’t tripped. 

Thermostat Settings

Mistaken thermostat settings often make pool heaters seem faulty. Verify that the thermostat is set to a temperature higher than the current water temperature.

Safety Switches

Many heaters come with built-in safety mechanisms that prevent them from turning on in certain conditions. Ensure that safety switches, like the high-limit switch or the rollout switch, are not engaged due to an underlying issue.

Fixes to Try:

• Test your thermostat by raising its temperature and seeing if the heater kicks in.
• Check for signs of gas leaks (for gas heaters) or damaged electrical wires (for electric heaters). Never attempt to repair gas lines or electrical components on your own—always contact a licensed technician.

3. The Heater is Leaking

Leaking water from your pool heater is never a good sign, but this issue can often be resolved quickly.

Inspect Heat Exchanger

Leaks in gas heaters can happen for a multitude of reasons. Some of those might include bad chemistry, sooting, gas flow restrictions, and even improper venting. Please contact us today to have a professional take a look

Loose Connections

Another common culprit is loose pipe connections. Take a close look at the inlet and outlet pipes to ensure the fittings are snug.

Fixes to Try:

• Tighten any loose fittings using a wrench (but don’t overdo it—you don’t want to crack the pipes).
• Balance your pool water chemistry to help prevent future damage to vital components.
• If the heat exchanger is damaged, it will likely need to be replaced—a job that should only be done by a qualified pool technician.

4. It’s Making Strange Noises

Is your pool heater growling, popping, or making other unusual sounds? Don’t ignore it—those noises may be a sign of a deeper issue.

Check for Mineral Buildup

• Over time, minerals in your pool water can deposit inside the system, leading to a condition known as scaling. Scaling can restrict water flow and cause odd noises. 

Air in the System

• Air trapped in the lines or the heater itself can also create banging or popping sounds. This often happens when the water levels in your pool are low.

Fixes to Try:

• Use a pool descaler product to clean out any scaling.
• Ensure your pool water is at the proper level and bleed air from the system by opening the air relief valve on your filter.

5. The Heater Won’t Reach My Desired Temperature

If your pool heater is running but the water just won’t warm up enough, it’s time to do some digging.

Evaluate Heater Size

• If your heater is undersized for your pool, it may struggle to reach and maintain your desired temperature. Calculate your pool’s volume and compare it to the heater’s BTU rating for compatibility. A professional can help you determine the ideal heater size based on your pool’s dimensions and usage habits.

Clean the Components

• A dirty filter, clogged burner jets, or debris on the heat exchanger can all prevent your heater from functioning efficiently.

Check External Factors

• External factors like cold weather or extreme wind are regular culprits when it comes to a pool heater not working. Consider investing in a solar cover or windbreak to help retain heat.

Fixes to Try:

• Backwash or replace your pool filter.
• Manually clean the heat exchanger following your manufacturer’s instructions.
• Use a solar cover to retain heat overnight or during cooler weather.

Get Back to Enjoying Your Pool with Aqua Masters

Dealing with a pool heater that’s not working properly can be frustrating, but you don’t need to tackle it alone. At Aqua Masters, we specialize in diagnosing and repairing pool heater issues quickly and effectively. With years of experience and a commitment to exceptional service, we’re here to help you get back to what matters—enjoying your pool!

Contact us today to schedule a repair or get advice on how to maintain your heater for optimal performance.