A pool heat pump is a great investment for extending your swimming season and maintaining a comfortable water temperature. But like any mechanical system, it can develop issues over time. Knowing how to recognize and resolve common problems can save you time, money, and frustration. Here are some of the most frequent pool heat pump problems and how to fix them.

1. Heat Pump Not Turning On

Possible Causes:

• Tripped circuit breaker

• Faulty thermostat

• Power supply issues

How to Fix: Start by checking your breaker box to ensure the circuit hasn’t tripped. If it has, reset it and see if the unit powers on. Next, inspect the thermostat settings—make sure it’s set to a temperature higher than the current water temperature. If the unit still won’t start, there may be an issue with the wiring or control board, and it’s best to call a qualified technician.

2. Not Heating the Pool Properly

Possible Causes:

• Dirty or clogged air filter

• Low ambient air temperature

• Low refrigerant levels

• Scale buildup on the heat exchanger

How to Fix: Ensure the air filter is clean and unobstructed. Since pool heat pumps rely on warm outside air to operate efficiently, they may struggle in cooler conditions. If the outside air temperature is below 50°F (10°C), heating performance will drop. If the unit is clean but still underperforming, low refrigerant or internal scaling may be the cause—both require a professional to diagnose and repair.

3. Heat Pump is Running, but Water is Cold

Possible Causes:

• Bypassed water flow

• Dirty evaporator coil

• Incorrect water flow rate

How to Fix: Check the plumbing to make sure water isn’t bypassing the heat pump. Also, inspect the evaporator coil for dirt or debris—if it’s dirty, clean it carefully with a soft brush or use a coil cleaner. Make sure the pool pump is providing sufficient water flow; low flow rates can prevent the heat pump from transferring heat effectively. Cleaning the pump basket and backwashing the filter may help.

4. Strange Noises Coming from the Unit

Possible Causes:

• Loose parts

• Debris in the fan

• Worn compressor or motor

How to Fix: Turn off the power and inspect the fan for any visible debris or obstructions. Tighten any loose screws or panels. If the noise persists or sounds mechanical (like grinding or banging), it could be a sign of a failing motor or compressor—these should be assessed by a technician.

5. Unit Keeps Shutting Off

Possible Causes:

• Overheating

• Faulty sensors or switches

• Inconsistent power supply

How to Fix: Check for proper ventilation around the unit and clear away any obstructions. Overheating can trigger automatic shutdowns. If airflow is fine, there may be an issue with a sensor or high-pressure switch, which should be tested and replaced by a professional if needed.

Final Thoughts

While pool heat pumps are generally reliable, issues can and do arise. Regular maintenance—like cleaning filters, inspecting coils, and checking for obstructions—can prevent many common problems. When in doubt, consult your owner’s manual or hire a licensed technician. A little troubleshooting can go a long way in keeping your pool warm and your heat pump running smoothly.