White Rodgers 50a55-286 System Lockout And Diagnostic Features, System Lockout Features

SYSTEM LOCKOUT AND

DIAGNOSTIC FEATURES

SYSTEM LOCKOUT FEATURES

When system lockout occurs, the gas valve is de-ener- gized, 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 continu- ously 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, interrupt- ing 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 50A55 control continuously monitors its own opera- tion and the operation of the system. If a failure occurs, the LED will indicate a failure code as shown below. If the failure is internal to the control, the light will stay on continuously. In this case, the entire control should be replaced, as the control is not field-repairable.

If the sensed failure is in the system (external to the control), the LED will flash 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). If more than one failure is detected, the LED will alternate through all the failure codes that apply.

Continuous flashing	Low flame sense signal
(no pause)
1 flash, then pause	Lockout caused by flame sensed
	when there should be no flame
2 flashes, then pause	Pressure switch stuck closed
3 flashes, then pause	Pressure switch stuck open
4 flashes, then pause	High limit open
5 flashes, then pause	Rollout switch open or rollout
	sensed
6 flashes, then pause	*Lockout caused by pressure
	switch opening 4 times in one
	cycle
7 flashes, then pause	*Lockout caused by no ignition
	(after 3 trials)
8 flashes, then pause	*Lockout caused by loss of flame
	5 times in one heating cycle
9 flashes, then pause	115 Volt AC power reversed/
	improper ground
12 flashes, then pause	Ignitor relay sense error

The LED will also flash once at power-up.

*Will automatically restart from lockout after one hour. All other conditions need to be cleared for the control to resume normal operation.

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