tS
AquaCal Startup Timeout / No Heat Produced

Display shows tS or TIMEOUT; unit attempts to start but times out.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Compressor not starting, Reversing valve stuck (on heat/cool models), Control board not energizing outputs, Internal overloads tripping

How to Fix / Troubleshooting

Safety first: Disconnect power before accessing internal components.

  • Observe startup: Restore power and command heat. Confirm that the fan starts and listen for the compressor. If the compressor never starts, suspect contactor, capacitor, or compressor.
  • Check contactor coil: Verify the compressor contactor is being energized by the control board. Replace if the coil is open or contacts are burnt.
  • Capacitor test: Inspect and test the compressor start/run capacitor. Replace if out of tolerance.
  • Technician diagnosis: If tS persists, a technician should evaluate compressor health and control board outputs.
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Repair Difficulty

Professional Required 5/5

Required Part

Compressor Contactor
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