Enable/ Disable Switch; Power Supply Test - A.O. Smith Cyclone XL 100 Series Service Handbook

Ground Terminal
Heater Wiring
(Factory Installed)
Lead Wire
Ground
L1 (Black Wire)
Neutral (White Wire)
Firere 19. Jenction Box Assembly

ENABLE/ DISABLE SWITCH

The Enable/Disable Switch is NOT an "on/off" switch and does not disconnect 120 volt power to the CCB and other heater components.
When in the "Disabled" position the switch removes electrical power from the Gas Control Valve so that water heating is disabled. The
display, CCB, and other electrical components will still be energized and the display will read "Water Heating Disabled". The Enable/
Disable Switch can be used to disable operation and reset error codes. To operate the water heater, make sure the switch is set to
"Enabled" position. Turn power off at the source (circuit breaker) during installation and servicing.

POWER SUPPLY TEST

Proper grounding and polarity can be verified with an AC volt meter by taking three voltage readings at the power supply wiring inside
the water heater's 120 VAC junction box.
CHECK FOR AC VOLTAGE BETWEEN:
1. Hot & Neutral - should be approximately 120 VAC.
2. Hot & Ground - should be approximately 120 VAC.
3. Neutral & Ground - should be approximately 0 VAC.
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