Carrier 30RBM 160 Installation, Operation And Maintenance Instructions

Also see for 30RBM 160: Installation, operation and maintenance instructions

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Carrier 30RBM 160 Installation, Operation And Maintenance Instructions Manual pdf 35 page image

359.4 - Units with hydronic module and variable speedpump – Temperature differential controlThe system flow rate is not set at a nominal value.The flow rate will be adjusted, by varying the pump speed, tomaintain a heat exchanger temperature differential valuedefined by the user.This is checked by the temperature sensors at the waterexchanger inlet and outlet (items 8 and 9 on the main watercircuit diagram).The system reads the measured temperature values, calculatesthe corresponding temperature delta, compares it with thesetpoint value set by the user and then modulates the pumpspeed module.• This results in an increase in the flow rate if thetemperature delta exceeds the setpoint.• This results in a decrease in the flow rate if the temperaturedelta is less than the setpoint.This modulation is limited only by the maximum and minimumflow rates for the unit and by the maximum and minimumallowable pump speeds.The maintained temperature delta may, in certain cases, differfrom the setpoint value:• if the setpoint value is too high (obtained for a flow ratelower than the minimum value or a frequency less thanthe minimum value), the system will stop once it reachesthe minimum flow rate or minimum frequency, which willresult in a temperature delta below the setpoint,• if the setpoint value is too low (obtained for a flow ratehigher than the maximum value or a frequency greaterthan the maximum value), the system will stop once itreaches the maximum flow rate or maximum frequency,which will result in a temperature delta above the setpoint.Contact the manufacturer's service department to implementthe procedures described below.Hydronic circuit cleaning procedureRefer to the hydronic circuit cleaning procedure.Procedure for controlling the temperature delta setpointOnce the circuit is cleaned, stop the forced start of the pumpand proceed to the configuration of the unit for the requiredcontrol mode.Modify the control parameters:• Water flow rate control method (temperature differential)• Set the value of the required differential temperature.The unit's default factory configuration is the minimum speed(frequency: 30 Hz).9.5 - Units with hydronic module and variable speedpump – Setting a fixed flow rate for the systemThe flow will be set to a nominal value. This value will remainconstant and will not be dependent on variations in thesystem's load.Contact the manufacturer's service department to implementthe procedures described belowHydronic circuit cleaning procedureRefer to the hydronic circuit cleaning procedure.Procedure for controlling the flow rateOnce the circuit has been cleaned, set the required water flowrate by adjusting the pump frequency on the user interface.Stop the forced operation of the pump and proceed to theconfiguration of the unit for the required control mode. Modifythe control parameters:• Water flow rate control method (fixed speed)• Constant frequency value.The unit's default factory configuration is the minimum speed(frequency: 30 Hz).