Bradford White 120T400, Руководство по установке и эксплуатации

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DIAGNOSTIC ERROR CODES AND TROUBLESHOOTING PROCEDURES FOR 120T MODELS WITH HONEYWELL
LOW FIRE START CONTROL SYSTEM
Error Code Definition of Code Cause of Problem and Actions Taken to Correct
No code –
blank display

Check power supply to the water heater.

Make sure water heater is plugged in and the breaker is on.
 Check if there is 120 volts power supply to the LINE connections on the
control board.

If 120 volts is present, check for 24 volts output to SECONDARY
terminals on the Control Board.
 Check for loose wires, defective transformer.
 Check wire harness connections from display to the control board.
3-48, 58-60 Internal Faults
 Verify wiring to the wiring diagram.

Check power supply to make sure voltage and frequency is correct.

Check for 24 volts from the transformer to the control board.
 Reset module by interrupting power or pressing the reset button on the
module.
49 Voltage too low or high
 Measure the incoming line voltage.

Voltage should be 115-125 volts.

If the voltage is not within this range or there is drastic fluctuation, then
have the incoming power supply checked.
 If the line voltage is satisfactory, check the output from the transformer
to make sure it is 22-26 volts.
 Replace transformer or wiring if defective.
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AC Inputs phase
reversed
 Check the module and display connections.

Check the module power supply and make sure that frequency, voltage
and VA capacity of the transformer meet specifications.

Check to make sure the wiring connections on the control module from
terminals J4-10 and J8-2 are connected together.
62 Fan speed not proved
 Check the PWM (tachometer for blower speed – “Pulse With
Modulation”) wire harness connection from the blower to the control
module.
 Make sure the pin terminals make solid contact.

Measure the resistance of each wire in the wire harness from the
terminal ends.
 Replace wire harness if defective.
67 ILK Off (Interlock Off)
 Check wiring to the normally closed blocked vent pressure switch and
high limit switch.

Use a voltmeter to find out if the pressure switch or the high limit switch
has opened.
 If so, determine the cause (blocked vent terminal, clogged condensate
drain, high temperature in compartment).

If limit switch is closed, check wiring for shorts.

Measure continuity.
 If limit switch and wiring check O.K., replace control module.
80
High Limit (Overheat
Condition)
 Check the wiring from the sensor to the control module.
 Measure the resistance of each outside wire to the center wire.

If either outside wire has a much different resistance reading, replace
the sensor.
 Check water temp at nearest point of use to the water heater, if water
temp is above 200°F replace the sensor, if below 200°F replace the
control module.

Make sure the sensor is securely held inside the well with the clip.
 If the problem persists and the sensor and wiring check O.K., then
replace the control module.
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