Daikin MicroTech III DPS Installation And Maintenance Manual

Contents

Daikin MicroTech III DPS Installation And Maintenance Manual Manual pdf 49 page image

Operator’s Guidewww DaikinApplied com49 OM 1263 • MICROTECH UNIT CONTROLLERInitialization to Standby for RestartThe Compressor Cooling State transitions from Initializationto Standby for Restart if one of the Compressor Protectionfunctions force a transition to Standby for Restart, the invertercompressor or outdoor fan board requests a transition toStandby for Restart or if all compressor operation becomesdisabled for any reasonNormal to PumpdownThe Compressor Cooling State transitions from Normal toPumpdown if there is no longer a call for cooling operationNormal to Standby for RestartThe Compressor Cooling State transitions from Normal toStandby for Restart if one of the Compressor Protectionfunctions force a transition to Standby for Restart, the invertercompressor or outdoor fan board requests a transition toStandby for Restart or if all compressor operation becomesdisabled for any reasonPumpdown to Standby for RestartThe Compressor Cooling State transitions from Pumpdownto Standby for Restart if one of the Compressor Protectionfunctions force a transition to Standby for Restart, the invertercompressor or outdoor fan board requests a transition toStandby for Restart or if all compressor operation becomesdisabled for any reasonPumpdown to InitializationThe Compressor Cooling State transitions from Pumpdownto initialization if there is a call for cooling or dehumidificationoperationStandby for Restart to OffThe Compressor Cooling State transitions from Standby forRestart to OFF after the cooling stage timer expiresInverter Compressor Cooling OperationRebel units are always equipped with an inverter compressor.A fixed speed compressor is also provided on sizes 7.5–12,25–28 tonsThe primary control devices related to inverter compressoroperation are the following:• Inverter and Fixed Speed Compressors (INV, Comp3 )• 1 or 2 Outdoor Fan(s)• 4 Way Reversing Valve (4WV) – Heat Pump Units Only• Refrigerant Receiver Solenoid Valve (SVR) – Heat PumpUnits Only• Refrigerant Discharge to Suction Bypass Solenoid Valve(SVB)• Indoor Coil Expansion Valve (EVI)• Outdoor Coil Expansion Valve (EVO) – Heat Pump UnitsOnlyControl of these devices is described in the following sectionsInput DevicesPTS (suction refrigerant pressure) – MicroTech III AIPTD (discharge refrigerant pressure) – MicroTech III AIDRT1 (INV compressor discharge refrigerant line temperature)– MicroTech III AIDRT3 (compressor discharge refrigerant line temperature) –MicroTech III AISRT (suction refrigerant temperature) – MicroTech III AIDFT (defrost temperature) – MicroTech III AIIRT (indoor refrigerant temperature) – IFB (heat pump)ORT (outdoor refrigerant temperature) – IFB (heat pump)Compressor ControlDPS units will utilize one of the following Compressor CoolingConfigurations:• Single inverter compressor (INV) on sizes 3–6 tons,16–20 tons• Single inverter compressor (INV) and a standardcompressor on all other sizesWhen compressor operation is active the combination ofinverter and standard compressors is controlled to maintain theapplicable cooling capacity input of the manual controlThe control of the inverter compressor is accomplished bysending the analog output of a PI_Loop via Modbus to theinverter compressor control board As the PI_Loop outputvaries from 0-100% the speed of the inverter compressorincreases from 0 to maximum In the case where the unit isalso equipped with standard (fixed) compressor, the fixedcompressor is started and stopped via a digital outputUpon an increasing call for cooling the inverter compressoris modulated to its maximum capacity before the fixedcompressor is turned ON. When the load is such that the fixedcompressor is required, the inverter compressor is slowed toits minimum speed before turning on the fixed compressor. Theinverter compressor is then modulated to maintain the loadUpon a decreasing call for cooling the inverter compressor ismodulated to its minimum speed before the fixed compressoris turned OFF. Once the fixed compressor is turned off theinverter compressor is modulated maintain the load