Er4
Aquaterra Spas Heater Relay or Current Sense Error

Display shows Er4 or ERR4, heater and pumps may be disabled.

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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

Stuck heater relay on control board, Heater drawing abnormal current, Shorted heater element, Control board current sensor failure

How to Fix / Troubleshooting

Safety first: Turn off power at the breaker. Do not attempt to run the spa until the heater circuit is inspected.

  • Visual inspection: Open the control pack and look for burnt marks near the heater relay or terminals.
  • Check heater connections: Ensure heater wires are tight and not discolored from overheating.
  • Test heater resistance: Using a multimeter (only if you are qualified), measure the resistance of the heater element and compare to Aquaterra specifications. A shorted or open heater must be replaced.

Because Er4 involves high-voltage heater circuits, professional service is strongly recommended.

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Repair Difficulty

Professional Required 5/5

Required Part

Heater Assembly
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