Why Is My Pool Heater Not Heating?

Quick answer: Most pool heater problems come from low water flow, a thermostat set below the current water temperature, a gas or power supply issue, or a fault code. Check those first.

Common causes

• Thermostat set too low
• Dirty filter or closed valves causing low flow
• Gas valve off or empty propane tank
• Tripped breaker
• Heat pump in cold weather, which heats more slowly

What to do

• Set the thermostat above the water temperature and confirm the heater is on
• Confirm the pump is running and filter pressure is normal
• Check the gas supply and the breaker
• Write down any fault code shown on the display

When to call a pro

If you smell gas, leave the area and call the gas company. For repeat faults or ignition problems, call a pro.