Display shows EC or ECON and spa heats slowly or not to the expected temperature.

Note: EC is typically a mode indicator, not an error.

• Check mode: Use the topside control to cycle through modes (Standard, Economy, Sleep). Set to Standard for continuous temperature maintenance.
• Verify set temperature: Increase the set temperature to the desired level.
• Adjust filter cycles: Ensure filtration/heating cycles are long enough to maintain temperature, especially in cold climates.

If the spa remains in EC and will not change modes, the topside control or main board may require service.