A224_F: Flame Status Circuit Failure
Status
This is a critical fault and should rarely (if ever) be seen in the field.
Description
The control’s internal circuitry fails to properly sense the presence or absence of flame.
Expected Operation
If the flame status circuit fails, the unit will respond as follows:
1. Gas valve and igniter will turn off (if not already off).
2. Inducer will immediately be energized at high speed (if not already at high speed).
3. Indoor blower (IBM) will energize at the high heat speed unless there is another call also present – in which case the higher speed shall be used.
4. "A224_F Flame Status Circuit Failure” alarm will be logged.
These states will remain as described above until the condition is gone.
Once this condition is no longer present, the furnace will clear the alarm "A224_F Flame Status Circuit Failure", complete the inducer post-purge and the user set heat blower off delay. The control then proceeds to a one-hour "soft" lockout with alarm "A116_F One-hour Lockout: Flame Presence Alarm" declared throughout the duration. Upon completion of the lockout, control will clear alarm "A116_F One-hour Lockout: Flame Presence Alarm" and resume normal operation.
Cause
1. Faulty furnace control.
2. Flame sense wire is grounded.
3. 24VDC for blower control on the IFC is grounded, check if removing blower harness fixes the fault.
Solution
1. Replace furnace control (IFC).
2. Replace flame sense rod and cable. Should not be grounded.
3. Replace indoor blower motor if blower control is grounding 24VDC on the IFC board.
