Heater runs but pool water does not reach set temperature; unit cycles on and off frequently.

Safety first: Turn off power before cleaning coils or accessing sensors.

• Verify expectations: Check AquaCal's performance charts for your model versus pool size and ambient conditions. Heat pumps raise temperature slowly, often 1–2°F per hour under ideal conditions.
• Use a pool cover: Install and use a solar or thermal cover, especially at night, to reduce heat loss.
• Check setpoint and mode: Ensure the thermostat is set correctly and that the unit is in HEAT mode, not COOL or AUTO with conflicting settings.
• Clean evaporator coil: Remove debris and rinse the coil to restore airflow and efficiency.
• Sensor check: Compare displayed water temperature to an independent thermometer. If the heater thinks the water is warmer than it is, replace or relocate the water sensor.