Bradford White U-TW4-75S-76R-3N - Manual (Page 14)

Page 14
Abnormal Operation (cont’d)
B) If the resistance is below 3000 ohms: The gas control immediately
turns off all outputs and proceeds to flash 8 times then 1 time with a
three second pause. The error self clears if the resistance returns to nor-
mal range for at least 15 seconds.
2. Temperature Sensor Fault:
A) Temperature Sensor Open Circuit: The gas control immediately turns
off all outputs and proceeds to flash 8 times then 3 times with a three
second pause. The error self clears if the fault clears for at least 15 sec-
onds.
B) Thermal well sensors not reading the same temperature within
±5.5°F: The gas control immediately turns off all outputs and proceeds
to flash 8 times then 3 times with three second pause. The error self
clears if the fault clears for at least 15 seconds.
C) Water Temperature in excess of ECO (Energy Cut Off) Limit: The gas
control immediately turns off the pilot and main valves. The gas control
LED proceeds to flash 4 times with a 3 second pause.
To reset the gas control, rotate the setpoint knob to the minimum set-
ting for at least 6 seconds before returning to desired temperature set-
ting.
3. Pressure Switch/Blower Temperature Fault:
A) Pressure switch closed at start of call for heat: The gas control waits 4
seconds then, proceeds to flash 2 times with a 3 second pause. The
gas control waits 2 minutes and then turns on the blower for 30 sec-
onds. The blower turns off after 30 seconds and the control waits for
the pressure switch to open. Any time the pressure switch opens, the
blower turns on (or stays on) and the control proceeds to wait for the
pressure switch to close.
Sequence of Operation
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