Daikin DPS Installation And Maintenance Manual

Also see for DPS: Installation and maintenance manual Installation and maintenance manual Installation manual Installation and maintenance manual

Contents

Daikin DPS Installation And Maintenance Manual Manual pdf 87 page image

Inverter Compressor Cooling StateDescriptionsThe Inverter Compressor Cooling State determines theoperation of the following devices:• Inverter Compressor• Fixed Speed Compressor (if present)• Outdoor Fan(s)• 4 Way Reversing Valve (4WV) (Heat Pump only)• Outdoor Expansion Valve (EVO) (Heat Pump only)• Indoor Expansion Valve (EVI)• Receiver Solenoid Valve (SVR) (Heat Pump only)• Bypass Solenoid Valve (SVB)Cooling OffCompressor cooling operation begins in the Cooling Off stateAll devices are Off or closed The state remains Off until thereis a call for cooling or dehumidificationPre Start Pressure EqualizationIn the Pre Start Pressure Equalization state the SVB valveis opened to divert hot gas leaving the compressor directlyto the suction line to equalize the pressures in the systembefore beginning compressor operation Operation remains inthis state for 30 seconds [adjustable ] When in the Pre StartPressure Equalization state, all devices are off or closed,except the Outdoor Fan and SVB The Outdoor fan speed isset to 50%InitializationIn the Initialization state either the Standard Initializationor Alternate Initialization sequence is used in order tomanage refrigerant and to assure a 4-way valve is switchedThe Alternate Initialization sequence is used on invertercompressor units the first time the unit enters cooling after unitpower up, the compressors had last operated in heating, or if ithas been a long time since cooling has operated and it is coldoutdoorsOtherwise the Standard Initialization Sequence is normally usedTable 61: Standard Initialization SequenceDevice Step 1 Step 2 Step 3 Step 4Inverter Compressor & Comp 3 Inverter Compressor Speed= MinimumComp3=OffInverter Compressor Speed=Smaller of Step 12 or MaximumComp3=Off ← AInverter Compressor Only Inverter Compressor Speed= MinimumIf OAT≥50°F or RAT≥73°F, Inverter CompressorSpeed=Smaller of Step 12 or MaximumIf OAT<50°F & RAT<73°F, Inverter Compressor Speed=Minimum← AOutdoor Fan Outdoor Fan=0% if OAT<68°FOutdoor Fan=50% if OAT≥68°F B ← ←4 Way Valve (Heat Pump) OFF ← ← ←Outdoor CoilExpansion Valve (EVO)(Heat Pump only)EVO=100% ← ← ←SVR (Heat Pump only) Closed ← ← ←SVBNormally OpenClose if either of the following is true:60 seconds elapses from the beginningof Step 1Discharge superheat>9°F← ← ←Indoor CoilExpansion Valve (EVI) EVI= 0% C ← ←Time Duration 10 seconds 5 seconds 5 seconds DA Inverter compressor speed is increased until the 4-way valve is seated (discharge minus suction pressure >57 psi) and as longas the suction pressure is above 43 psi Comp 3 remains OFFB Outdoor fan capacity is controlled to maintain the discharge pressure between 256 psi and 313 psi Outdoor fan capacity isset to 100% if discharge pressure is above 384 psi Outdoor fan capacity runs at least at minimum capacity if inverter board(fin) temperature >167°FC The indoor expansion valve is controlled to keep the suction superheat between 3 6°F and 9 0°FD Standard Initialization lasts a maximum 140 seconds It is completed early anywhere between 20 seconds and 140 secondsif the saturated suction temperature is high (above 118°F), the suction pressure is low (below 79 psi) or once the 4-wayvalve is seated (differential pressure above 57 psi, suction pressure below 142 psi and suction or discharge superheatabove 27°F)operator ’s guIdewww DaikinApplied com87 OM 1141-3 • MICROTECH UNIT CONTROLLER