Reasons Why Your Pool Heater is Malfunctioning

The heater for your pool is vital to keep the temperature of your water comfy, give you an extended swim season, and protect your investment; however, when it no longer functions correctly, it can quickly make your pool unusable.

By knowing the most common causes of issues related to a malfunctioning pool heater, you can help to identify early issues and minimize the risk of expensive repair costs. Below is a list of the most frequently seen causes of pool heater issues, as well as what they mean to your unit.

9 Reasons Why Your Pool Heater is Malfunctioning

1. Dirty or Clogged Filter

Restricted water flow is one of the primary reasons that pool heaters have issues and fail to function properly. Dirty or clogged pool filters reduce water circulation in the pool, which may cause the heater to turn off as a safety feature.

Signs to look for:

• The heater turns on and then turns off quickly
• Low pool water pressure
• Heater error codes indicate low water flow.

Solution: Clean the filter and perform a backwash, and restore appropriate water circulation in the pool.

2. Thermostat Problems

In your heating system, an incorrectly calibrated or otherwise faulty thermostat can cause your heater to not heat properly. In some cases, a faulty thermostat won’t accurately read the temperature of the water and send the proper signal to turn on the heater.

Look for the following signs:

• Water temperature is inconsistent
• The heater does not respond to changes in temperature

Solution: Test your thermostat with an infrared thermometer, and recalibrate your thermostat if necessary; if you cannot calibrate your thermostat properly, you may need to replace it with a new one.

3. Ignition Failure (Gas Heaters)

The ignition system on a Gas Pool Heater is the part that ignites gas to start heating the water. If the pilot light or electronic ignition has an issue, the heater will not turn on.

Common Problems:

• Defective Ignition Switch
• Gas Supply Problems
• Dirty Burners

Solution: Verify that there is a gas supply to the heater, clean the burners, and inspect the ignition components. It’s usually best to have a qualified technician service the heater.

4. Electrical Issues (Electric or Heat Pump Heaters)

Issues with the electrical system can cause issues with your heater’s ability to turn on and operate at maximum efficiency. Possible problems include tripped circuit breakers, loose connections, and/or defective parts.

Indicators of problems include:

• Heater not powering up
• Breaker continues to trip
• Odor coming from the heater (burning)

Solution: Reset the circuit breaker and check for loose connections. If you are unsure of how to make your own electrical repairs, you will want to contact a qualified technician.

5. Low Refrigerant Levels (Heat Pumps)

Low refrigerant levels are poor at heating your pool with a heat pump, using reduced efficiency. You may notice the following signs:

• The heater turns on, but the water doesn’t get hot
• Ice on the unit
• Strange sounds

Solution: A professional diagnosis is required to resolve refrigerant problems and to recharge the refrigerant.

6. Corrosion and Scale Build-Up

Corrosion that occurs from poor water chemistry is often responsible for internal heater component failure, including the heat exchanger. Corroded components will show the following signs:

• Rust or visible scale on heaters
• Reduced heating performance
• Leakage from the heater

Mitigation strategies include: Maintaining a balanced chemistry in the pool and adhering to a regular schedule for heater maintenance.

7. Faulty Pressure Switch

A pressure switch will be triggered when a consistent flow of water is available; once this occurs, the heater will begin to operate; however, if there is a problem with the pressure switch, then the heater will not operate.

Signs of this type of problem include:

• Heater won’t start despite proper flow
• Flow-related error codes

Solution: If a problem does exist, have the pressure switch inspected and or replaced

8. Blocked or Dirty Heat Exchanger

Debris and scale can build up inside the heat exchanger over time, which will impede the ability of the heat exchanger to transfer heat efficiently.

Signs of this type of problem include the heater:

• Running longer than normal.
• Raising the utility bill.
• Providing insufficient heat.

In the event of a clogged heat exchanger, cleaning by a licensed heating technician will likely be required to restore the unit to normal operation.

9. Incorrect Pool Heater Size

An oversized heater will have trouble keeping your pool at its ideal setting. Examples to look out for:

• Heater takes longer than expected to raise the water temperature
• Heater runs continuously
• Heater can’t reach the set point temperature

Solution: Contact a pool professional to determine that the heater is sized correctly.

When to Call a Professional

While minor issues like filter cleaning can be handled independently, more complex problems involving gas lines, electrical systems, or refrigerant should always be addressed by a certified pool technician. Routine inspections and seasonal servicing can prevent most heater failures before they become serious.

Get Your Pool Heater Back on Track with Perfect Pools

If your pool heater has stopped heating your pool the way it should, you should not wait for the situation to worsen. Experienced technicians at Perfect Pools have the expertise to diagnose and repair pool heaters of any kind, including all types of gas or electric heaters and heat pump systems.

Whether you need a simple repair on your existing heater or a complete replacement, we will get your pool to the right temperature as quickly and efficiently as possible.

Contact us at Perfect Pools now to set up a professional inspection so that you can continue to enjoy the benefits of having a warm, efficient pool to swim in all year long.