Bard WH381 Installation Instructions Manual

Manual 2100-342IPage 19 of 24FIGURE 14DEFROST CONTROL BOARDBe careful not to touch any other terminals with theinstrument used to short the SPEEDUP terminals. Itmay take up to 10 seconds with the SPEEDUPterminals shorted for the speedup to be completed andthe defrost cycle to start.As soon as the defrost cycle kicks in remove theshorting instrument from the SPEEDUP terminals.Otherwise the timing will remain accelerated and runthrough the 1-minute minimum defrost length sequencein a matter of seconds and will automatically terminatethe defrost sequence.There is an initiate defrost jumper (sen jump) on thecontrol that can be used at any outdoor ambient duringthe heating cycle to simulate a 0° coil temperature.This can be used to check defrost operation of the unitwithout waiting for the outdoor ambient to fall into thedefrost region.By placing a jumper across the SEN JMP terminals (a1/4 inch QC terminal works best) the defrost sensormounted on the outdoor coil is shunted out and willactivate the timing circuit. This permits the defrostcycle to be checked out in warmer weather conditionswithout the outdoor temperature having to fall into thedefrost region.In order to terminate the defrost test the SEN JMPjumper must be removed. If left in place too long thecompressor could stop due to the high pressure controlopening because of high pressure condition created byoperating in the cooling mode with outdoor fan off.Pressure will rise fairly fast as there is likely no actualfrost on the outdoor coil in this artificial test condition.There is also a 5-minute compressor time delay functionbuilt into the HPC. This is to protect the compressor fromshort cycling conditions. In some instances it is helpful tothe service technician to override or speed up this timingperiod, and shorting out the SPEEDUP terminals for a fewseconds can do this.