Ducane (HVAC) 2HP13/14 warranty Outdoor Unit Defrost Control Board, Defrost Control Timing Pins

intervals. If the defrost therm ostat is closed when the selected com pressor run tim e interval ends (call for defrost), the defrost relay is energized and defrost begins. The factory setting is 60 m inutes. However, if frost

accumulation is easily cleared, the optim um efficiency setting is 90 m inutes.

Outdoor Unit Defrost Control Board

Defrost Control Timing Pins

Each tim ing pin selection provides a different accumulated compressor run tim e period for one defrost cycle. This tim e period m ust occur before a defrost cycle is initiated. The defrost interval can be adjusted to 30 (/T1), 60 (T2), or 90 (T3) minutes. The defrost tim ing jum per is factory-installed to provided a 90-m inute defrost interval. If the tim ing selector jum per is not in place the control defaults to a 90-m inute defrost interval. The m axim um defrost period is 14 minutes and cannot be adjusted.

A TEST option is provided for troubleshooting. The

TEST mode may be started any time the unit is in the heating mode and the defrost thermostat is closed or jumpered. If the jum per is in the TEST position at power- up, the control will ignore the test pins. W hen the jum per is placed across the TEST pins for 2 seconds, the control will enter the defrost mode. If the jum per is rem oved before an additional 5 second period has elapsed ( 7 seconds total), the unit will rem ain in defrost m ode until the defrost therm ostat opens or 14 minutes have passed. If the jum per is not rem oved until after the additional 5 second period has elapsed, the defrost will term inate and the test option will not function again until the jum per is rem oved and re-applied.

Compressor Delay

The defrost board has a field-selectable function to reduce occasional sounds that may occur while the unit is cycling in and out of the defrost m ode. The com pressor will be cycled "off" for 30 seconds going in and out of the

defrost m ode when the com pressor delay jum per is rem oved.

NOTE: The 30 second "off" cycle is not functional when jum pering the TEST pins.

Time Delay

The tim ed-off delay is 5 minutes long. The delay help to protect the com pressor from short-cycling in case the power to the unit is interrupted or a pressure switch opens. The delay is bypassed by placing the tim er select jum per across the TEST pins for 0.5 seconds.

Pressure Switch Circuit

The defrost control incorporates 2 pressure switch circuits. The optional high pressure switch connects to the boards HI PS term inals. The low pressure switch is factory installed.

During a single dem and cycle, the defrost control will lock out the unit after the fifth tim e that the circuit is interrupted by any pressure switch wired to the control board. In addition, the diagnostic LEDs will indicate a locked-out pressure switch after the fifth occurrence of an open pressure switch. The unit will rem ain locked out until power to the board is interrupted, then re-established or until the jum per is applied to the TEST pins for 0.5 seconds.

NOTE: The defrost control board ignores input from the

low-pressure switch term inals as follows:

!During the TEST mode,

!During the defrost cycle,

!During the 90 second start-up period,

!and for the first 90 seconds each tim e the reversing valve switches heat/cool m odes. If the TEST pins are jumpered and the 5 minute delay is being by- passed, the LO PS terminal signal is not ignored during the 90 second start-up period.

Diagnostic LEDS

The defrost board uses 2 LEDs for diagnostics. The

LEDs flash a specific sequence according to the condition.

Defrost Control board Diagnostic LED

Mode	Green LED (DS2)	Red LED (DS1)
No power to control	OFF	OFF
Normal operation/	Simultaneous Slow FLASH
power to control
Anti-short cycle	Alternating Slow FLASH
lockout
Low pressure switch	OFF	Slow FLASH
fault (Optional)
Low pressure switch	OFF	ON
lockout (Optional)
High pressure switch	Slow FLASH	OFF
fault (Optional)
High pressure Switch	ON	OFF

lockout (Optional)

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