The control will store the last 5 error codes. As new error codes are stored, the oldest is deleted.
The stored error codes can be recalled by pressing the LAST ERROR button for one to five seconds with no thermostat inputs to the board.
The display will show the last 5 error codes, the most recent first.
Fault codes can be cleared by pressing the LAST ERROR button for more than 5 seconds.
- The control will flash both LEDs twice to indicate that the memory has been cleared.

X/L Output Categories:

X/L	Condition
2 flashes	Soft lockout - Reset with interruption of thermostat call.
3 flashes	Hard lockout - Reset by cycling power to air handler.
4 flashes	Wiring, sensor or control setting error.

Status Code Display:

LED 1 (Red)	LED 2 (Green)	X/L	Description
Off	Off		No power to control
Off	On		1st stage operation (2 stage units only)
On	On		2nd stage compressor or full capacity
Off	2sec On, 2sec Off		Normal operation, no compressor
Off	Rapid flash		Call for compressor, short-cycle delay active

Operational Fault Codes:

LED 1 (Red)	LED 2 (Green)	X/L	Description
On	Off	4	Control Failure
1 flash	Off	Off	High-pressure switch (not in lockout yet)
2 flash	Off	2 or 3	High-pressure switch lockout - heat or cool
3 flash	Off	2 or 3	High-pressure switch lockout - defrost
4 flash	Off	2 or 3	Low-pressure switch lockout
5 flash	Off	Off	Low voltage (< 19V)
6 flash	Off	Off	Low voltage (< 16V)
7 flash	Off	Off	Pipe freeze protection alert

Sensor or Switch Fault Codes:

LED 1 (Red)	LED 2 (Green)	X/L	Description
On	1 flash	2	Outdoor sensor shorted
On	2 flash	2	Outdoor sensor open
On	3 flash	2	Liquid line sensor shorted
On	4 flash	2	Liquid line sensor open
On	5 flash	2 or 3	High discharge line temperature
On	6 flash	2 or 3	Low discharge line temperature
On	7 flash	2	Discharge line sensor shorted
On	8 flash	2	Bonnet sensor shorted
On	9 flash	Off	Fossil fuel mode setting error

Wiring-related Fault Codes:

LED 1 (Red)	LED 2 (Green)	X/L	Description
1 flash	On	3	Compressor contactor miswired
2 flash	On	Off	Y2 present without Y1
4 flash	On	Off	O signal received in A/C-Only Mode
5 flash	On	Off	W signal received in A/C-Only Mode
6 flash	On	Off	W & O signal received in A/C-Only Mode
7 flash	On	Off	W & O signal received in H/P Mode
8 flash	On	Off	Defrost Curve Jumper Error