Carrier WSHP Open v3 Integration Manual

Also see for WSHP Open v3: Integration guide

WSHP Open v3 19Waterside economizerThe WSHP Open can provide modulating, or 2-position water economizer operation (for a field-installedeconomizer coil mounted to the entering return air side of the unit and connected to the condenser water loop), inorder to provide free cooling or preheating, when water conditions are optimal. Water economizer settings can beaccessed on Properties > Equipment > Status.The following conditions must be true for economizer operation:• SAT reading is available• EWT reading is available• If occupied, the SPT is greater than the occupied cooling setpoint or less than the occupied heating setpointand the condenser water is suitable• Space temperature reading is valid• If unoccupied, the SPT is greater than the unoccupied cooling setpoint, or less than the unoccupied heatingsetpoint, and the condenser water is suitableModulating water/2-Position water economizer control - modulates a water valve to control condenser waterflowing through a coil on the entering air side of the unit• Cooling - Provides an economizer cooling function by using the water loop when the entering water looptemperature is at least 5°F below space temperature. If the water loop conditions are suitable, the valvemodulates open to maintain a Supply Air Temperature that meets the load conditions. If the economizer coilcapacity alone is insufficient for a period greater than 5 minutes, or if a high humidity condition occurs, thenthe compressor starts, in order to satisfy the load. If the SAT approaches the Minimum Cooling SAT limit(HOME > CONFIG > UNIT), the economizer valve modulates closed during compressor operation.• Heating - In addition, the control modulates the water valve if the entering condenser water loop temperatureis suitable for heating (at least 5°F above space temperature) and heat is required. The valve is controlled ina similar manner, except to satisfy the heating requirement. If the coil capacity alone is insufficient to satisfythe space load conditions for more than 5 minutes, then the compressor starts in order to satisfy the load. Ifthe SAT approaches the Maximum Heating SAT limit, the economizer valve modulates closed duringcompressor operation.2-position water economizer control - has the capability to control a NO or NC, 2-position water valve to controlcondenser water flow through a coil on the entering air side of the unit.• Cooling - The purpose is to provide a cooling economizer function directly from the condenser water loopwhen the entering water loop temperature is at least 5° F below space temperature. If the optional coil isprovided and the water loop conditions are suitable, then the valve opens to provide cooling to the space,when required. If the capacity is insufficient for a period greater than 5 minutes, or if a high humiditycondition occurs, the compressor is started in order to satisfy the load. If the SAT reaches the MinimumCooling SAT limit, the economizer valve closes during compressor operation.• Heating - In addition, the economizer control opens the water valve, if the entering water loop temperature issuitable for heating (at least 5° F above space temperature) and heat is required. The valve is controlled in asimilar manner, except to satisfy the heating requirement. If the coil capacity is insufficient to satisfy thespace load for more than 5 minutes, then the compressor is started to satisfy the load. If the SAT reaches theMaximum Heating SAT limit, the economizer valve closes during compressor operation.