Bradford White EF120T4003N3, Руководство по обслуживанию

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120T Control Board Schematic
Troubleshooting
System Observation for 120T400/500 Models with Direct Spark Ignition
Water Heater Fault: Water heater does NOT operate.
Display Error Code: Water heater digital display does
NOT operate - blank display.
Is 24-28 VAC present
between red and black wire
pin connections on the back
of control board?
Verify secondary voltage at the control
board.
Refer to control board illustration.
Voltage at connector location J8 across
blue and yellow wires should be 24-28
VAC. If not, check transformer. Replace
transformer if defective.
Does the water heater digital
display operate? Increase
thermostat setting if tank is warm.
Digital display
operates– see
next page.
Check main power supply to water heater.
Check fuse, circuit breaker, plug receptacle, line
cord, and wiring to water heater.
Check to make sure switch on front of control
board is in the ON position.
Replace digital display.
Replace control board.
Check wire
harness for proper
continuity.
Check wires for proper
termination to control board. Are
wire terminations connected
properly to digital display?
N
Y
N
Y
Y
Refer to control board illustration.
Voltage at transformer across black and
white wires should be 110-120 VAC.
Verify 120V from the power switch.
Verify primary voltage at the transformer.
WARNING
120 volt potential exposure. Use caution making
voltage checks to avoid personal injury.
CAUTION
Use caution to NOT damage connectors when
making voltage measurements or jumping terminals.
Black & White
wires
Yellow & Blue
wires
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