Digital control will not start the pool pump; display shows E01 and pump does not run.

Safety First: Turn OFF power at the pool sub‑panel breaker and verify with a non‑contact voltage tester before opening any covers.

• Check supply voltage: Remove the Rheem pump control cover. With a multimeter and power restored, measure voltage at the LINE terminals feeding the pump. Compare to the nameplate (typically 230V ±10%). If voltage is low, contact an electrician to correct the supply.
• Inspect wiring connections: Turn power OFF again. Tighten all line, neutral, and ground screws at the pump terminal block and at any external Rheem control box or timer. Look for heat discoloration or melted insulation and repair/replace damaged conductors.
• Check wire gauge and run length: If the pump is far from the panel and wired with small gauge wire, excessive voltage drop can trigger E01. Consult Rheem installation manual for recommended wire size and upgrade if needed.
• Inspect internal relay/contactor: On models with an integrated Rheem control module, inspect the power relay or contactor for pitted or burned contacts. Replace the control module or relay assembly if contacts are damaged.
• Reset the control: After corrections, turn power OFF for 2–3 minutes, then restore power and attempt to start the pump. If E01 persists with correct voltage, the control board may be defective.