Electrical Requirements; Grounding And Polarity; Power Supply Test - State Water Heaters 120 Series Service Handbook

electrical reQuirements

The water heaters covered in this manual require a 120 VAC (Volts Alternating Current) 1Ø (Single Phase)
power supply. The maximum AC amperage is approximately 5.2 FLA (full load amps) during the Igniter Warm
up operating state. Residential models are factory equipped with a 3 prong appliance cord that plugs into a
standard 120 VAC wall outlet. Commercial models are not equipped with an appliance cord; an appliance
cord or hard wiring will have to be field installed, see Commercial And Residential Models on page 46.

grounding and polarity

The water heaters covered in this manual must be properly grounded and the polarity of the power supply
must be correct. Correct polarity wiring for a standard 120 VAC residential wall outlet is shown in Figure 2
below, note the downward orientation of the ground connection socket.
The hot and neutral wires from the power supply must connect to the black (hot) and white (neutral) wires
respectively inside the 120 VAC junction box on the water heater, see Figure 4 on page 9 for junction box
location. The ground wire from the power supply must connect to the green wire inside the 120 VAC junction
box on the water heater.
A "Reversed Polarity" condition occurs when the hot and neutral wires are connected in reverse from what
is shown in Figure 2. If the power supply polarity is reversed it will cause AC Reversed fault conditions and
Control System lock outs. If the water heater is not grounded properly it will cause Ignition Failure fault
conditions and Control System lock outs, see Flame Sensor on page 18 and the Power Supply Test below.
120 VAC POWER SUPPLY
HOT
(typically black)
120 VOLTS

power supply test

Proper grounding and polarity can be verified with an AC volt meter by taking three voltage readings at the
wall outlet being used or the power supply wiring inside the water heater's 120 VAC junction box. Inexpensive
plug in outlet testers, available at most home centers and hardware stores, can be used to quickly verify
proper grounding and correct polarity at a 120 VAC wall outlet, see Figure 2 above.
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.
6
NEUTRAL GROUND
(typically white) (typically green)
0 VOLTS
120 VOLTS
Servicing should only be performed by a Qualified Service Agent
POLARITY CORRECT WIRING
120 VAC WALL OUTLET
NEUTRAL
PLUG IN OUTLET TESTER
Figure 2
HOT
GROUND