Carrier AQUAZONE 50RHC Installation And Service Instructions Manual

Also see for AQUAZONE 50RHC: Operating and troubleshooting

Contents

Carrier AQUAZONE 50RHC Installation And Service Instructions Manual Manual pdf 31 page image

31boilerless operation mode, only the compressor is used forheating when FP1 is above the boilerless changeover tempera-ture set by switch 8 below. Select ON for normal operation orselect OFF for boilerless operation.Boilerless Changeover Temperature — Switch 8 on S1 pro-vides selection of boilerless changeover temperature set point.Select OFF for set point of 50 F or select ON for set pointof 40 F.If switch 8 is set for 50 F, then the compressor will be usedfor heating as long as the FP1 is above 50 F. The compressorwill not be used for heating when the FP1 is below 50 F and thecompressor will operates in emergency heat mode, staging onEH1 and EH2 to provide heat. If a thermal switch is being usedinstead of the FP1 thermistor, only the compressor will be usedfor heating mode when the FP1 terminals are closed. If the FP1terminals are open, the compressor is not used and the controlgoes into emergency heat mode.DIP SWITCH BLOCK 2 (S2) — This set of DIP switches isused to configure accessory relay options. See Fig. 20.Switches 1 to 3 — These DIP switches provide selectionof Accessory 1 relay options. See Table 14 for DIP switchcombinations.Switches 4 to 6 — These DIP switches provide selectionof Accessory 2 relay options. See Table 15 for DIP switchcombinations.Table 14 — DIP Switch Block S2 —Accessory 1 Relay OptionsLEGENDNOTE: All other DIP switch combinations are invalid.Table 15 — DIP Switch Block S2 —Accessory 2 Relay OptionsLEGENDNOTE: All other switch combinations are invalid.Auto Dehumidification Mode or High Fan Mode — Switch 7provides selection of auto dehumidification fan mode or highfan mode. In auto dehumidification fan mode the fan speedrelay will remain off during cooling stage 2 if terminal H isactive. In high fan mode, the fan enable and fan speed relayswill turn on when terminal H is active. Set the switch to ON forauto dehumidification fan mode or to OFF for high fan mode.Switch 8 — Not used.Units with Modulating Hot Water Reheat(HWR) Option — A heat pump equipped with Hot WaterReheat (HWR) can operate in three modes: cooling, coolingwith reheat, and heating. The cooling and heating modes arelike other Aquazone™ water source heat pumps. The reversingvalve ("O" signal) is energized in cooling, along with the com-pressor contactor(s) and blower relay. In the heating mode, thereversing valve is deenergized. Almost any thermostat willactivate the heat pump in heating or cooling modes. TheDeluxe D microprocessor board, which is standard with theHWR option, will accept either heat pump (Y,O) thermostatsor non-heat pump (Y,W) thermostats.The reheat mode requires either a separate humidistat/dehumidistat or a thermostat that has an integrated dehumidifi-cation function for activation. The Deluxe D board is config-ured to work with either a humidistat or dehumidistat input toterminal “H” (DIP switch settings for the Deluxe D board areshown in Table 16). Upon receiving an “H” input, the DeluxeD board will activate the cooling mode and engage reheat.Table 16 — Humidistat/Dehumidistat Logic andDeluxe D DIP Switch SettingsTable 17 shows the relationship between thermostat inputsignals and unit operation. There are four operational inputs forsingle stage units and six operational inputs for dual stageunits:• Fan Only• Cooling Stage 1• Cooling Stage 2• Heating Stage 1• Heating Stage 2• Reheat ModeMODULATING HWR APPLICATION CONSIDER-ATIONS — Unlike most hot gas reheat options, the mod-ulating HWR option (RVC,RHS,RVS,RDS only) will oper-ate over a wide range of entering-water temperatures(EWTs). Special flow regulation (water regulating valve) isnot required for low EWT conditions. However, below 55 F,supply-air temperatures cannot be maintained at 72 Fbecause the cooling capacity exceeds the reheat coil capac-ity at low water temperatures. Below 55 F, essentially allwater is diverted to the reheat coil (no heat of rejection tothe building loop). Although the HWR option will work finewith low EWTs, overcooling of the space may result withwell water systems or, on rare occasions, with ground loop(geothermal) systems (NOTE: Extended range units arerequired for well water and ground loop systems). Sincedehumidification is generally only required in cooling, mostground loop systems will not experience overcooling of thesupply-air temperature. If overcooling of the space is a con-cern (e.g., computer room well water application), auxiliaryheating may be required to maintain space temperaturewhen the unit is operating in the dehumidification mode.Water source heat pumps with HWR should not be used asmakeup air units. These applications should use equipmentspecifically designed for makeup air.HWR COMPONENT FUNCTIONS — The proportionalcontroller operates on 24 VAC power supply and automaticallyadjusts the water valve based on the supply-air sensor. Thesupply-air sensor senses supply-air temperature at the blowerinlet, providing the input signal necessary for the proportionalcontrol to drive the motorized valve during the reheat mode ofoperation. The motorized valve is a proportional actuator/three-way valve combination used to divert the condenser waterfrom the coax to the hydronic reheat coil during the reheatmode of operation. The proportional controller sends a signalto the motorized valve based on the supply-air temperaturereading from the supply air sensor.The loop pump circulates condenser water through the hy-dronic reheat coil during the reheat mode of operation (refer toFig. 28). In this application, the loop pump is only energizedACCESSORY 1RELAY OPTIONSDIP SWITCH POSITION1 2 3Cycle with Fan On On OnDigital NSB Off On OnWater Valve — Slow Opening On Off OnOAD On On OffNSB — Night SetbackOAD — Outside Air DamperACCESSORY 2RELAY OPTIONSDIP SWITCH POSITION4 5 6Cycle with Fan On On OnDigital NSB Off On OnWater Valve — Slow Opening On Off OnOAD On On OffNSB — Night SetbackOAD — Outside Air DamperSensor 2.1 2.2 2.3 Logic Reheat(ON) - HReheat(OFF) - HHumidistat Off Off Off Reverse 0 VAC 24 VACDehumidistat Off On Off Standard 24 VAC 0 VAC