E30
Rheem Low Voltage / Power Supply Fault

Heater shows E30 and will not start; often associated with low-voltage issues

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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

Undervoltage at power terminals, Loose line connections, Shared circuit overloaded, Failing transformer (if used)

How to Fix / Troubleshooting

Safety First: Turn off power at the breaker before opening the electrical compartment.

  • Measure line voltage: With a multimeter and power restored, verify voltage at the heater's input terminals matches the nameplate rating. If low, correct the supply issue.
  • Inspect connections: Tighten all line and neutral/ground lugs. Look for discoloration or melted insulation indicating overheating.
  • Dedicated circuit: Ensure the heater is on a dedicated circuit sized per Rheem's installation manual. Remove other loads if sharing is causing voltage drop.
  • Check internal transformer (if present): With power off, inspect the low-voltage transformer for overheating or buzzing. Replace with a Rheem-specified transformer if defective.
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Repair Difficulty

Medium 3/5

Required Part

Power Supply Wiring / Transformer
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