Carrier 30RQ 039 Series Installation, Operation And Maintenance Instructions

Contents

4218.3 - InstallationThe water connections on the desuperheater water inletsand outlets must not cause any mechanical local constraintat the heat exchangers. If necessary, install flexible connectionsleeves.Install water flow control and balancing valves at the heatexchanger outlet.The volume of the desuperheater circuit water loop mustbe as low as possible so that the temperature can increaserapidly when the unit is started up.The minimum entering water temperature at the desuper-heater is 25°C. This requires the use of a three-way valve (item31 in the diagram), with a controller and the sensor controllingthe minimum required entering water temperature.The desuperheater water loop must include a safety valveand an expansion tank. When selecting these, consider thewater loop volume and the maximum temperature (90°C)when pump operation is stopped (item 20 in the diagram).18.4 - Control configuration with the desuperheateroptionThe unit can operate in two modes.18.4.1 - Efficiency priority mode (standard)In this mode unit control optimises unit efficiency. Heatreclaim is based on the saturated condensing temperature.The percentage of the reclaimed heating capacity comparedwith the total capacity rejected by the condenser increasesin proportion to the saturated condensing temperature. Thistemperature is directly linked to the condenser enteringair temperature (entering air temperature in cooling modeand water temperature in heating mode).18.4.2 - Reclaim priority modeIn cooling mode only this configuration allows the user toenter a setpoint that is relative to the minimum condensingtemperature (default = 40°C) to increase the heatingcapacity reclaimed at the desuperheaters, if required. Thisconfiguration is only effective if the desuperheater contact isactivated on the control board (user connection block).This function is not available for 30RQSY units.For setpoint control of the minimum saturated condensingtemperature and to find the position of the connectionblock on the board refer to the 30RB/RQ 017-160 Pro-Dialog+ control manual.Other parameters directly affecting the effective capacityreclaimed at the desuperheater are principally:• The unit load rates, that decide whether the unitoperates at full load (100%) or part load.• The water entering temperature in the desuperheateras well as the condenser entering air temperature.18.5 - Operating limitsDesuperheater Minimum MaximumEntering water temperature at start-up °C 25* 60Leaving water temperature during operation °C 30 65air condenser Minimum MaximumOutside operating temperature °C -10 46* The entering water temperature at start-up must not be lower than 25°C. Forinstallations with a lower temperature a three-way valve is necessary.19 - BRINE OpTION (OpTION 5B & OpTION 6B)This option allows production of brine down to 0°C(option 5B) / -15°C (option 6B). The unit is equipped withsuction pipe insulation (option 6B only) and a fanfrequency converter.The operating range is a function of the suction pressure,which in turn is a function of:- the brine type,- the brine concentration,- the flow rate,- the brine temperature,- the condensing pressure (ambient temperature).Example: For operation with ethylene glycol at 45% and abrine temperature of -15°C (entering temperature -10°C),the maximum outside operating temperature will be around33°C.Operating range with 45% ethylene glycolOperating range with 45% ethylene glycolOutside air temperature, °CEvaporator leaving water temperature, °COption 5BOption 6B-25-15-551525354555-20 -15 -10 -5 0 5 10Outside air temperature, °CEvaporator leaving water temperature, °C19.1 – frost protectionThe evaporator low pressure and frost protection dependson the amount of antifreeze added to the water circuit. Theevaporator approach (LWT - SST) as well as frost protectionare based on this amount).It is therefore essential to control the amount of antifreezein the water loop at the first start-up (circulate for 30 minutesto ensure good homogeneity of the mixture before takingthe sample). Refer to the manufacturer’s data to define thefrost protection, based on the concentration rate measured.The frost protection temperature must be used in the unitsoftware parameters.Option 5BOption 6B