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

Safety first: No internal electrical work is required for this issue, but always keep water balanced and GFCI protected.

EC/ECO is usually not a fault but an indication that the spa is in an energy-saving mode where heating occurs only during filter cycles.

• Check mode setting: Use the topside control panel to view the current mode (Standard, Economy, Sleep, etc.). Refer to your American Whirlpool manual for button combinations to change modes.
• Switch to Standard mode: Set the spa to Standard or Ready mode so it maintains the set temperature continuously.
• Review filter cycles: Ensure filter cycles are long enough and scheduled appropriately so the spa has time to heat, especially in cold weather.
• Monitor temperature: After changing settings, allow several hours for the spa to reach the new set temperature.

If the spa still does not heat properly in Standard mode, there may be a separate heater or sensor issue that requires diagnosis.