Heater runs but pool water does not reach set temperature or heats very slowly

Safety first: Ensure normal operation and no leaks before extended runtime.

• Verify setpoint: Confirm the Poolworld heater set temperature is higher than the current water temperature and that the mode is set to Pool or Spa as needed.
• Check flow rate: Ensure valves are correctly positioned and the pump is running at the recommended speed for heating. Clean the filter and baskets.
• Use a pool cover: Cover the pool when not in use to reduce heat loss from evaporation and wind, especially at night.
• Compare to capacity: Check the heater BTU rating against your pool volume and climate. If undersized, longer run times or a larger heater may be required.

Note: In cold or windy conditions, even a properly sized heater may take many hours to raise pool temperature.