Ducane (HVAC) 2HP13 warranty Time Delay, Pressure Switch Circuit, Diagnostic Leds

defrost), the defrost relay is energized and defrost begins. The factory setting is 60 minutes. However, if frost accumulation is easily cleared, the optimum efficiency setting is 90 minutes.

Outdoor Unit Defrost Control Board

Defrost Control Timing Pins

Each timing pin selection provides a different accumulated compressor run time period for one defrost cycle. This time period must occur before a defrost cycle is initiated. The defrost interval can be adjusted to 30 (/T1), 60 (T2), or 90 (T3) minutes. The defrost timing jumper is factory-installed to provided a 90-minute defrost interval. If the timing selector jumper is not in place the control defaults to a 90-minute defrost interval. The maximum 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 jumper is in the TEST position at power- up, the control will ignore the test pins. When the jumper is placed across the TEST pins for 2 seconds, the control will enter the defrost mode. If the jumper is removed before an additional 5 second period has elapsed ( 7 seconds total), the unit will remain in defrost mode until the defrost thermostat opens or 14 minutes have passed. If the jumper is not removed until after the additional 5 second period has elapsed, the defrost will terminate and the test option will not function again until the jumper is removed 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 mode. The compressor will be cycled "off" for 30 seconds going in and out of the defrost mode when the compressor delay jumper is

removed.

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

Time Delay

The timed-off delay is 5 minutes long. The delay help to protect the compressor from short-cycling in case the power to the unit is interrupted or a pressure switch opens. The delay is bypassed by placing the timer select jumper 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 terminals. The low pressure switch is factory installed.

During a single demand cycle, the defrost control will lock out the unit after the fifth time 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 remain locked out until power to the board is interrupted, then re-established or until the jumper is applied to the TEST pins for 0.5 seconds.

NOTE: The defrost control board ignores input from the

low-pressure switch terminals as follows:

!During the TEST mode,

!During the defrost cycle,

!During the 90 second start-up period,

!and for the first 90 seconds each time the reversing valve switches heat/cool modes. 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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