Electrical Requirements - A.O. Smith BTX-100 Service Handbook

ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUAL

ELECTRICAL REQUIREMENTS

The water heater covered by this Service Manual must be grounded in accordance with
the local codes, or in the absence of local codes: the National Electrical Code (NFPA 70) or
the Canadian Electrical Code (C22.1).
The water heater covered by this Service Manual requires a 120 VAC 1Ø (single phase)
power supply. It is factory equipped with a standard 3 prong appliance cord that plugs into a
standard 120 VAC wall outlet. 5.2 FLA (full load amps) approximate.
As shown in the illustration below there should be 120 VAC present between the power
supply hot and ground wires. 120 VAC should also present between the hot and neutral
wires. There should be 0 VAC present between the neutral and ground wires.
Correct wiring for a standard 120 VAC wall outlet is also shown in the Illustration below. Note
the orientation of the ground connect is at the bottom. Reversed polarity is when the hot and
neutral wires are connected opposite from what is shown here.
Service Notes - Electrical
This water heater is a polarity sensitive appliance and will not operate if the power supply
polarity is reversed. If the polarity of the power supply is reversed the water heater's control
system will declare a fault condition and display "AC Reversed" on the UIM display.
The water heater's burner must be grounded for flame sensing current to be established and
verify ignition. If the burner is not grounded the water heater's control system will declare a
fault condition and display "Ignition Failure" on the UIM display after 3 failed ignition trials.
Also shown is an outlet tester that will quickly determine if the plug is wired correctly. These
testers will also diagnose reversed polarity, open ground and open neutral wire problems.
Outlet testers are inexpensive and simple to use. They are available at most hardware
stores and home centers.
120 VAC 1Ø Power Supply
HOT
120 volts
Technical Literature Department
NEUTRAL GROUND
0 volts
120 volts
Servicing should only be performed by a Qualified Service Agent
Correctly Wired Outlet
Neutral
8 of 52
120 VAC 1Ø
Wall Outlet
Outlet Tester
Ashland City, TN © 2008
Hot
Ground