Display shows EC or ECO, and the spa heats less frequently; temperature may drop between cycles.

Safety first: No electrical hazard; this is typically a settings issue.

• Check heating mode:
  • Review the USSPA user manual for mode descriptions (Standard, Economy, Sleep).
  • Use the mode button or menu to switch back to Standard mode if continuous heating is desired.
• Verify filtration cycles:
  • In Economy mode, heating may occur only during filtration cycles; adjust cycle times if needed.