Spa heats very slowly or cannot reach set temperature, especially in cold weather.

Safety: No internal electrical work is required for basic checks.

• Step 1 – Verify mode: Ensure the spa is in Standard mode so the heater can run as needed.
• Step 2 – Inspect cover: Check the AquaRest spa cover for waterlogging, tears, or poor fit. Replace if heavy or not sealing properly.
• Step 3 – Check cabinet insulation: Inspect access panels and cabinet for missing or displaced insulation, especially in windy outdoor installations.
• Step 4 – Clean filter and confirm flow: A restricted filter can reduce heater efficiency. Clean or replace the filter cartridge.

If heating remains inadequate with good insulation and flow, the heater may be partially scaled or failing and should be tested and possibly replaced.