E18 error occurs, and the unit indicates a low-voltage or power supply fault.

Safety first: Disconnect power before touching wiring.

• Check outlet: Plug a lamp or tester into the outlet to confirm stable power. Avoid using extension cords.
• Inspect transformer: Ensure the Waterguy power adapter matches the voltage and amperage specified on the control head label. Replace if warm, noisy, or discolored.
• Direct connection: Plug the transformer directly into the wall outlet, not a power strip, to reduce voltage drop.
• Board inspection: If E18 persists with a new adapter, the control board may have an internal short and should be replaced.