Carrier Atmosphera 42EM series Installation Instructions Manual

Also see for Atmosphera 42EM series: Manual Installation, operation and maintenance instructions

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Carrier Atmosphera 42EM series Installation Instructions Manual Manual pdf 13 page image

13Options a and b: the diameter of the spigot housing thefresh air flow controller is 125 mm.The 16.6 1/s (60 m3/h) fresh air controller may be modifiedon site by relocating or removing two plastic restrictors inorder to increase the maximum constant fresh air flowcapacity to 44.4 1/s (160 m3 /h). A label on the 42EM showshow to adjust the two plastic restrictors (Fig. 11).Modification procedure• Disconnect the fresh air duct from the spigot on theAtmosphera.• Remove or reposition the two plastic restrictors,following the fresh air flow controller.• Reconnect the fresh air duct to the spigot.IMPORTANT: If the Atmosphera is fitted with a returnair temperature sensor, the constant fresh air flow ratemust not exceed 50% of the supply air flow delivered bythe unit at minimum speed.NOTE: To operate correctly, the 8.3 l/s (30 m3/h) constantfresh air flow controller requires a differential pressure inthe range 50 Pa to 200 Pa. The 16.6 l/s (60 m3/h) constantfresh air controller requires a differential pressure in therange 70 to 200 Pa.4.5.2 - Fresh air controller with variable air volumeThe 42EM Atmosphera can be equipped with an optionalvariable fresh air flow controller from 0 to 55 l/s (0 to 200m3/h).This is connected to the numeric Carrier controller andcan regulate the fresh air intake in two ways:• either using a fixed rate set by the installer that can bereconfigured as required• or based on the CO2 level; in this case it is connectedto a CO2 sensor via the Carrier numeric controller(the CO2 sensor is located opposite the fresh air inlet).NOTE: With the variable fresh air flow controller theupstream pressure in the fresh air duct must be 180 Pa.4.6 - optional water flow control valvesThese valves are two-way or four-way type, with a bodydesigned to withstand a 16 bar operating pressure.4.6.1 - Electrothermal actuator (on/off)The actuator is a 230 V a.c. on/off type.To enable the installation to be filled with water, thewater circuits to be equalised and the units to be purged,the actuators must be connected to the power supply toopen the valves via a command from the wall thermostatsor from the BMS.4.6.2 - Actuator replacement procedureThe actuators on both the chilled water and the hot watervalves may be replaced if either develops a fault.• Disconnect the power supply to the unit before carryingout any work on a unit.• Disconnect the actuator power supply cable.- 230 V on/off type actuator used with the Carriernumeric controller: Disconnect the actuatorpower supply cable fitted with a quick connector.- 230 V on/off actuator used with an electronicthermostat: Remove the plastic protection coverheld in place with two screws. Disconnect theactuator power supply cable connected to thequick connector. This can be done by pressingdown the spring tongue using a screwdriver andpulling out the wire from the appropriate terminal.• Uncouple the faulty actuator. Refitting is by the reversalof the procedure described above.WARNING: Ensure that the actuator is firmly screwed tothe valve body (maximum torque 15 N·m).4.6.3 - Valve body replacement procedure• Disconnect the power supply before carrying out anywork on a unit.• Close the isolating valves on the manifolds.• Unscrew the union nuts to disconnect the flexible waterpipes.• Remove the valve actuators taking care to identify thecooling and heating valves.• Disconnect the flexible condensate drain pipe which isheld in place by a collar (the collar is not supplied byCarrier).• Remove the two-way or four-way water flow controlvalve bodies. Depending how the Atmosphera is con-figured, the four-way valve coupling may be fitted witha heating/cooling changeover switch, if so do notremove it.• Remove the 4 torx screws (T20) and slide out the coiland drain pan assembly.• Fit the new valve body to the coil (fit new gaskets).• Refit the coil and condensate assembly.• Reconnect the flexible condensate drain pipe which isheld in place by a collar (the collar is not supplied byCarrier).• Refit the valve actuators taking care to ensure thatthey are correctly fixed to the valve body.• Reconnect the flexible water pipes by tightening theunion nuts. Retighten all the water connections andensure that all gaskets have been changed and correctlyfitted (maximum torque 15 N·m).• Open the isolating valves on the manifolds and purgeall air from the system.• Check that there are no leaks and reconnect the powerto the Atmosphera.WARNING: When replacing a valve always ensure thatthe direction of flow through the valve is as shown by thearrow on the valve body. If the direction of flow is wrong,the valve body will deteriorate rapidly.