Bard W18HA-A Installation Instructions Manual

Bard W18HA-A Installation Instructions Manual Manual pdf 15 page image

Manual 2100-654CPage 15 of 34WIRING – MAIN POWERRefer to the unit rating plate for wire sizing informationand maximum fuse or circuit breaker size. Eachoutdoor unit is marked with a “Minimum CircuitAmpacity”. This means that the field wiring used mustbe sized to carry that amount of current. Dependingon the installed KW of electric heat, there may betwo field power circuits required. If this is the case,the unit serial plate will so indicate. All models aresuitable only for connection with copper wire. Eachunit and/or wiring diagram will be marked “Use CopperConductors Only”. These instructions must be adheredto. Refer to the National Electrical Code (NEC) forcomplete current carrying capacity data on the variousinsulation grades of wiring material. All wiring mustconform to NEC and all local codes.The electrical data lists fuse and wire sizes (75°Ccopper) for all models including the most commonlyused heater sizes. Also shown are the number of fieldpower circuits required for the various models withheaters.The unit rating plate lists a maximum fuse or circuitbreaker that is to be used with the equipment. Thecorrect size must be used for proper circuit protectionand also to assure that there will be no nuisancetripping due to the momentary high starting current ofthe compressor motor.The disconnect access door on this unit may be lockedto prevent unauthorized access to the disconnect. Toconvert for the locking capability, bend the tab locatedin the bottom left-hand corner of the disconnectopening under the disconnect access panel straightout. This tab will now line up with the slot in the door.When shut, a padlock may be placed through the holein the tab preventing entry.See page 20 for important information on three phasescroll compressor start ups.See Table 8 on page 30 for electrical specifications.WIRING – LOW VOLTAGE WIRINGAll 230/208V 1 phase and 3 phase equipment havedual primary voltage transformers. All equipmentleaves the factory wired on 240V tap. For 208Voperation, reconnect from 240V to 208V tap. Theacceptable operating voltage range for the 240 and208V taps are:TAP RANGE240 253 – 216208 220 – 187NOTE: The voltage should be measured at the fieldpower connection point in the unit and whilethe unit is operating at full load (maximumamperage operating condition).For low voltage wiring, an 18 gauge copper, color-codedcable is recommended. See Table 4 on page 16 formore information.Low Voltage ConnectionsThese units use a 24-volt AC low voltage circuit.The “RT” terminal is the 24V transformer output,and the “R” terminal is the 24VAC hot terminalfor the operation of the equipment. “RT” and “R”are connected with brass jumper bar which can beremoved and “RT” and “R” connected to externalNC (normally closed) contact such as a fire/smokedetector that will cause immediate shutdown of theequipment upon activation.“C” terminal is 24VAC common and is grounded.“G” terminal is the fan input.“Y1” terminal is the 1st Stage input for cooling.“Y2” terminal is the 2nd Stage compressor input forcooling (if equipped with an economizer).“B/W1” terminal is the reversing valve input. Thereversing valve must be energized for heating mode.“W2” terminal is the 2nd stage heat (if equipped).“W3” terminal is the emergency heat input. Thisterminal energizes the emergency heat relay. This isnot applicable on units with dehumification.“A” terminal is the ventilation input. This terminalenergizes any factory-installed ventilation option andindoor blower.“D” terminal is the dehumidification input. Ifinstalled, this terminal energizes any factory-installeddehumidification option."L/1" terminal is the compressor lockout output. Thisterminal is activated on a high or low pressure trip bythe electronic heat pump control. This is a 24VACoutput.LOW VOLTAGE CONNECTIONS FOR DDC CONTROLStandard Units Units w/EconomizersFan Only Energize G Energize G1st StageCooling Mode Energize Y1, G Energize Y1, G2nd StageCooling Mode Energize Y1, Y2, GHeat Pump Heating Energize Y1, G,B/W1Energize Y1, G,B/W12nd Stage Heatingw/heat pump(if employed)Energize Y1, G,B/W1, W2Energize Y1, G,B/W1, W2Ventilation Energize A Energize ADehumidification(if employed) Energize D Energize DEmergency Heat* Energize G, W2,W3Energize G, W2,W3* Not applicable on units with dehumidification