White Rodgers 50M56-7433 System Lockout And Diagnostic Features, System Lockout Features

SYSTEM LOCKOUT AND DIAGNOSTIC FEATURES

SYSTEM LOCKOUT FEATURES FAULT RECALL

When system lockout occurs, the gas valve is de-energized, the circulator blower is energized at heat speed, and, if flame is sensed, the inducer blower is energized. The diagnostic indicator light will flash or glow continuously to indicate system status. (System lockout will never override the precautionary features.)

To reset the control after system lockout, do one of the following:

1.Interrupt the call for heat or cool at the thermostat for at least one second but less than 20 seconds (if flame is sensed with the gas valve de-energized, interrupting the call for heat at the thermostat will not reset the control).

2.Interrupt the 24 VAC power at the control for at least one second. You may also need to reset the flame rollout sensor switch.

3.After one hour in lockout, the control will automatically reset itself.

DIAGNOSTIC FEATURES

The 50M56-743 control continuously monitors its own operation and the operation of the system. If a failure occurs, the LED will indicate a failure code as shown on page 8. If the failure is internal to the control, the LED will stay off or flash 8 times. In this case, the entire control should be replaced, as the control is not field-repairable.

Failure codes will flash the LED in the following flash- pause sequences to indicate failure status (each flash will last approximately 0.25 seconds, and each pause will last approximately 2 seconds).

The last five fault codes stored can be displayed on the diagnostic LED. When the control is in standby mode (no call for heat or cool), press the FAULT RECALL switch for approximately two seconds or until the diagnostic LED turns off. Release the switch and the LED will remain off for two seconds. Then the fault codes will display beginning with the most recent fault first with a two second pause between codes. After the stored fault codes have all displayed, the LED will remain off for two seconds and then turn on to indicate return to normal status. While displaying the stored fault codes, the control will ignore any new call for heat, cool or fan.

FAULT CODE RESET

The stored fault codes can be erased from memory. When the control is in standby mode (no call for heat or cool), press the FAULT RECALL switch for five to ten seconds or until the diagnostic LED begins to rapid flash. When the switch is released, the LED will turn off for two seconds to indicate the codes are erased. After two seconds the LED will turn on to indicate return to normal status. If the switch is held pressed for over ten seconds the rapid flash will stop and the LED will be on to indicate return to normal status.

The 50M56-743 has only one serviceable part –an automotive type fuse, which protects the low voltage transformer from damage if the output is short-circuited. If the fuse has opened up, remove whatever caused the short circuit and replace the fuse with only a 3 Amp automotive type fuse. If the fuse does not correct the condition, replace the entire 50M56-743 control. There are no other user serviceable parts.

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