2.Jumper the “T2”-”DFT” test pins. This will indicate to the board that the defrost T-stat is closed(if the compressor is running). Defrost T-stat is closed at 32° or below and is open at 68° or above. But it’s state is unknown if the temperature is between 32°F and 68°F. The defrost thermostat tells the board whether a defrost cycle needs to be started or terminated. With the DFT closed the unit will run for 30/60/90 minutes in heat mode and then defrost the outdoor coil. The defrost will turn off the outdoor fan, turn on the compressor and raise the coil temperature to 68°F. This will open the DFT and terminate the defrost. If the DFT does not open the defrost will end after 10 minutes.
3.Defrost board speed-up. With compressor running in heat mode, next jump the “Test” pin to “C” on terminal strip. This will initiate a defrost test in 5, 10 or 15 seconds (This is determined by the 30, 60 or 90 minute defrost pin settings. The factory setting will be 30 minutes). Note that this will bypass the compressor off delay when the unit goes into defrost test and if left in defrost test, the delay will be bypassed when the test is terminated by the processor. If the jumper is removed before the test is over the processor will perform the remainder of a normal defrost. See step 2 above.
4.Remove the jumpers.
Note: The delay/no-delay pin concerns compressor operation during defrosts.The default setting is delay. Reciprocating compressors should only use this setting in conjunction with an approved hard start kit. Scroll compressors that have noise issues while going into or coming out of defrost should use this 30 second delay to reduce the defrost noise.To switch from no-delay to delay remove the pin from the “no-delay” pin location and shift it to the “delay” pin location.
Speed up changes:
Manually initiating a defrost will cause the compressor to run continually when entering defrost.
Normal defrost operation:
To test normal defrost operation when the temperature is above 35°F, jumper “R” to “DFT” on the 624656 board and allow the unit to run for 30 minutes. Defrost will continue until the “R” to “DFT” jumper is removed or for 10 minutes. Remove the jumper.
The 5 minute time delay feature can be shortened 1 time to 1 second by jumping the “Test” to “C” terminal. Remove the jumper and repeat as desired.
Note: If jumper is left on the “Test” to “common” pins permanently, the defrost cycle will become inoperable.
Defrost Test Procedure for 624656
1.Jumper “T2” to “DFT” at the test terminals.
2.With unit running in heat mode, short the “TEST”terminal to the common terminal near it. This will speed up the board and cause it to enter defrost mode in 5/10/15 seconds depending on the defrost time selection. Compressor delay will not function during speed-up.
3.This test will end in 5 seconds if the “TEST”- common short is not removed.
4.Remove both the short and the “T2” to “DFT” jumper to terminate the defrost cycle. The 30 second compressor delay should operate normally.
5.Test is complete, reset thermostat to home owner preference.
