Carrier AQUASNAP MPW015-045 Operation And Service Manual

Also see for AQUASNAP 30MPA: User manual Installation instructions Controls, start-up, operation, service, and troubleshooting

212. Insert and secure the red (+) wire to terminal 5 of thespace temperature sensor terminal block.3. Insert and secure the white (ground) wire to terminal 4 ofthe space temperature sensor.4. Insert and secure the black (–) wire to terminal 2 of thespace temperature sensor.5. Connect the other end of the communication bus cable tothe remainder of the CCN communication bus.Energy Management Module (Fig. 10) — Thisfactory-installed option (FIOP) or field-installed accessory isused for the following types of temperature reset, demandlimit, and/or ice features:• 4 to 20 mA leaving fluid temperature reset (requiresfield-supplied 4 to 20 mA generator)• 4 to 20 mA cooling set point reset (requires field-supplied 4 to 20 mA generator)• Discrete inputs for 2-step demand limit (requires field-supplied dry contacts capable of handling a 24 vac,50 mA load)• 4 to 20 mA demand limit (requires field-supplied 4 to20 mA generator)• Discrete input for Ice Done switch (requires field-supplied dry contacts capable of handling a 24 vac,50 mA load)See Demand Limit and Temperature Reset sections onpages 27 and 31 for further details.Loss-of-Cooler Flow Protection — A proof-of-cooler flow device is factory installed in all chillers.Condenser Flow Protection — A proof-of-condens-er flow protection accessory can be field installed in the con-denser water piping of all chillers. The unit must be configuredfor the input to be enabled.Thermostatic Expansion Valves (TXV) — Allunits are equipped from the factory with conventional TXVs.The 30MPA units and 30MPW units with medium temperaturebrine also have factory-installed liquid line solenoids. The liq-uid line solenoid valves are not intended to be a mechanicalshut-off. For 30MPW units, when service is required, reclaimthe refrigerant from the system.For 30MPA units when service is required, the compressorand evaporator can be serviced by closing the factory-installedliquid line service valve and field-installed discharge line ser-vice valve. After the valves are closed, reclaim the refrigerantfrom the system.The TXV is set at the factory to maintain approximately 8 to12° F (4.4 to 6.7° C) suction superheat leaving the cooler bymonitoring the proper amount of refrigerant into the cooler. AllTXVs are adjustable, but should not be adjusted unless abso-lutely necessary.Capacity Control — The control system cycles com-pressors, digital scroll modulting solenoid (if equipped), andminimum load valve solenoids (if equipped) to maintain theuser-configured leaving chilled fluid temperature set point. En-tering fluid temperature is used by the main base board (MBB)to determine the temperature drop across the cooler and is usedin determining the optimum time to add or subtract capacitystages. The chilled fluid temperature set point can be automati-cally reset by the return fluid temperature, space, or outdoor-airtemperature reset features. It can also be reset from an external4 to 20-mA signal (requires energy management module FIOPor accessory).The capacity control algorithm runs every 30 seconds. Thealgorithm attempts to maintain the Control Point at the desiredset point. Each time it runs, the control reads the entering andleaving fluid temperatures. The control determines the rate atwhich conditions are changing and calculates 2 variables basedon these conditions. Next, a capacity ratio is calculated usingthe 2 variables to determine whether or not to make anychanges to the current stages of capacity. This ratio valueranges from –100 to +100%. If the next stage of capacity is acompressor, the control starts (stops) a compressor when theratio reaches +100% (–100%). If installed, the minimum loadvalve solenoid will be energized with the first stage of capacity.Minimum load valve value is a fixed 30% in the total capacitycalculation. The control will also use the minimum load valvesolenoid as the last stage of capacity before turning off the lastcompressor. A delay of 90 seconds occurs after each capacitystep change. Refer to Table 19.MINUTES LEFT FOR START — This value is displayedonly in the network display tables (using Service Tool,ComfortVIEW™ or ComfortWORKS® software) andrepresents the amount of time to elapse before the unit will startits initialization routine. This value can be zero without themachine running in many situations. This can include beingunoccupied, ENABLE/OFF/REMOTE CONTACT switch inthe OFF position, CCN not allowing unit to start, DemandLimit in effect, no call for cooling due to no load, and alarm oralert conditions present. If the machine should be running andnone of the above are true, a minimum off time (DELY, seebelow) may be in effect. The machine should start normallyonce the time limit has expired.MINUTES OFF TIME (ConfigurationOPT2DELY) — This user-configurable time period is used by thecontrol to determine how long unit operation is delayed afterpower is applied/restored to the unit. Typically, this time periodis configured when multiple machines are located on a singlesite. For example, this gives the user the ability to prevent allthe units from restarting at once after a power failure. A valueof zero for this variable does not mean that the unit should berunning.LEAD/LAG DETERMINATION — This is a configurablechoice and is factory set to be automatic for all units unless theunit is equipped with minimum load, then circuit A is lead(ConfigurationOPT2 LLCS). The value can be changedto Circuit A or Circuit B leading as desired. Set at automatic,the control will sum the current number of logged circuit startsand one-quarter of the current operating hours for each circuit.The circuit with the lowest sum is started first. Changes towhich circuit is the lead circuit and which is the lag are alsomade when total machine capacity is at 100% or when there isa change in the direction of capacity (increase or decrease) andeach circuit’s capacity is equal.CAPACITY CONTROL OVERRIDES — The following over-rides will modify the normal operation of the routine.Deadband Multiplier — The user configurable DeadbandMultiplier (ConfigurationSLCTZ.GN) has a defaultvalue of 1.0. The range is from 1.0 to 4.0. When set to otherthan 1.0, this factor is applied to the capacity Load/UnloadFactor. The larger this value is set, the longer the control willdelay between adding or removing stages of capacity. Figure11 shows how compressor starts can be reduced over time ifthe leaving water temperature is allowed to drift a largeramount above and below the set point. This value should be setin the range of 3.0 to 4.0 for systems with small loop volumes.Figure 12 shows the operating envelope for the compressor.CAUTIONCare should be taken when interfacing with other manufac-turer’s control systems due to possible power supplydifferences, full wave bridge versus half wave rectification.The two different power supplies cannot be mixed.ComfortLink™ controls use half wave rectification. Asignal isolation device should be utilized if a full wavebridge signal generating device is used.