Bard WH421 Installation Instructions Manual

Also see for WH421: Specifications Installation instructions

Manual 2100-399Page 14START UPIMPORTANT INSTALLER NOTEFor improved start-up performance, wash the indoorcoil with a dishwashing detergent.CRANKCASE HEATERSWA421 units are provided with compressor crankcaseheat. WH602 and WH483 units are not provided withcrankcase heat. These units utilize scroll compressorswhich do not require crankcase heat in this application.The WH421 models have an insertion well-type heaterlocated in the lower section of the compressor housingthis is a self-regulating type heater that draws onlyenough power to maintain the compressor at a safetemperature on these units.Some form of crankcase heat is essential to preventliquid refrigerant from migrating to the compressor,causing oil pump out on compressor start-up andpossible valve failure due to compressing a liquid.The decal in Figure 9 is affixed to all WA421 unitsdetailing start-up procedure. This is very important.Please read carefully.HIGH PRESSURE SWITCHThe WH483 and WH602 models are supplied with aremote reset high pressure switch. If tripped, thispressure switch may be reset by turning the thermostatoff then back on again.THREE PHASE SCROLL COMPRESSORSTART UP INFORMATIONScroll compressors, like several other types ofcompressors, will only compress in one rotationaldirection. Direction of rotation is not an issue withsingle phase compressors since they will always startand run in the proper direction.However, three phase compressors will rotate in eitherdirection depending upon phasing of the power. Sincethere is a 50-50 chance of connecting power in such away as to cause rotation in the reverse direction,verification of proper rotation must be made. All threephase units incorporate a phase monitor to ensure properfield wiring. See the Phase Monitor" on page 15 of thismanual.Verification of proper rotation must be made any timea compressor is change or rewired. If improper rotationis corrected at this time there will be no negative impacton the durability of the compressor. However, reverseoperation for over one hour may have a negative impacton the bearing due to oil pump out.NOTE:If compressor is allowed to run in reverserotation for several minutes, the compressor'sinternal protector will trip.All three phase ZR3 compressors are wired identicalinternally. As a result, once the correct phasing isdetermined for a specific system or installation,connecting properly phased power leads to the sameFusite terminal should maintain proper rotationdirection.Verification of proper rotation direction is made byobserving that suction pressure drops and dischargepressure rises when the compressor is energized.Reverse rotation also results in an elevated sound levelover that with correct rotations, as well as, substantiallyreduced current draw compared to tabulated values.The direction of rotation of the compressor may bechanged by reversing any two line connections to theunit.FIGURE 9START UP LABEL7961-411IMPORTANTTHESE PROCEDURES MUST BEFOLLOWED AT INITIAL START UPAND AT ANY TIME POWER HASBEEN REMOVED FOR 12 HOURSOR LONGER.TO PREVENT COMPRESSOR DAMAGEWHICH MAY RESULT FROM THE PRES-ENCE OF LIQUID REFRIGERANT IN THECOMPRESSOR CRANKCASE:1. MAKE CERTAIN THE ROOM THERMO-STAT IS IN THE “OFF“ POSITION. (THECOMPRESSOR IS NOT TO OPERATE.)2. APPLY POWER BY CLOSING THESYSTEM DISCONNECT SWITCH.THIS ENERGIZES THE COMPRES-SOR HEATER WHICH EVAPORATESTHE LIQUID REFRIGERANT IN THECRANKCASE.3. ALLOW 4 HOURS OR 60 MINUTESPER POUND OF REFRIGERANT INTHE SYSTEM AS NOTED ON THEUNIT RATING PLATE, WHICHEVER ISGREATER.4. AFTER PROPER ELAPSED TIME THETHERMOSTAT MAY BE SET TO OPER-ATE THE COMPRESSOR.5. EXCEPT AS REQUIRED FOR SAFETYWHILE SERVICING, DO NOT OPENSYSTEM DISCONNECT SWITCH.