Carrier 42NL series Installation, Operation And Maintenance Instructions

Also see for 42NH series: Installation, operation and maintenance instructions Original instructions

Contents

Carrier 42NL series Installation, Operation And Maintenance Instructions Manual pdf 20 page image

20ENGLISHIf several units are connected to a common collector, adevice must be installed (Fig. 11). Before operating the unit,ensure that the water flows into the internal condensatedrain pan by pouring some water into it. If problems aredetected, check the drain pipe slope and look for possibleobstructions. In all cases the connection duct(s) at the unitoutlet must be insulated to prevent any condensateformation on the walls.NOTE: The pressure losses of these ducts must becompatible with the unit performance. The duct must beas smooth as possible. Avoid sharp bends. Check that thereare no leaks or kinks, and that there is no dirt orinstallation debris inside the ducts. Debris within the ductsmight damage the fan wheel and the damper in the airdiffusers.When installation is complete - i.e. when the unit is attachedto the ceiling, air ducts are complete, water mani-folds arein position with stop valves ready on the connection stubs,and electrical installation is prepared - then connect thewater pipe (1/2” gas screw connector for size 2 to 5 ; 3/4”gas screw connector for size 6 and 7).WARNING: Be sure that the coil protective caps areremoved before connecting the water pipes (see Fig. 19).NOTE : Each fan-coil units shall be connected with waterflexible pipes in order to avoid any damage due tovibrations.Ensure that a gasket (not supplied by Carrier) is installedbetween the screw connector and the stop valve.When all units are installed, open the stop valves on themanifolds, bleed and then pressurize the circuits. To bleedthe coils, slightly loosen the bleed screws. The installationcan then be started.NOTE: Do not switch on the power until all connectionsare made and earthed.3.3 - Removal procedureSwitch off the unit power supply at the isolator providedfor the purpose during installation (isolator not suppliedby Carrier).• Disconnect the power supply and connection cables.• Close the isolating valves on the manifolds.• Disconnect the flexible water pipes by unscrewing thegas connectors.WARNING: Since the flexible water pipes do not havedrain valves, a receiver must be provided to allow thecooling coil to be drained.• Disconnect the supply air ducts.• Disconnect the flexible condensate drain pipe. Drainthe siphon into a suitable vessel.• Support the unit lightly and release it by unscrewingthe four nuts on the threaded hangers. Lower the unitcarefully.4 - COMPONENTS AND MAINTENANCE4.1 - Fan motor assembly4.1.1 - Fan assembly removal procedureWARNING: Disconnect the power supply to the unit beforecarrying out any work on the unit.• Identify and note the wired fan speeds. If the fandevelops a fault the whole assembly must be removedand replaced (Fig. 12).• Remove the filter.• Remove the fan access panel.• Disconnect the fan assembly power supply cables(power and control wiring for variable-speed motor).• If necessary remove the controller (fixed with screws)to gain access to the maintenance screws of the panelsupporting the fan.• The fan assembly and its panel are held in place by fourscrews. Remove these screws and slide the assembly down.• Remove the fan motor assembly.NOTE: Be careful not to touch the fan blades during theremoval process to avoid unbalancing the fans.• For units with the electric heater option, disconnectthe power supply cable to the heater. Withdraw thecable through the cable gland.• Unscrew the electric heaters.• Replacement of the fan motor assembly is by thereversal of the above procedure.WARNING: The electrical connections to the fan motormust be made in accordance with the labels on theconnector block4.1.2 - Capacitor replacement procedure• Disconnect the power supply to the unit beforecarrying any work on the unit.• Remove the filter.• Remove the fan motor assembly access panel.• Remove the capacitor that is attached to the motorchassis assembly.• Disconnect the capacitor by withdrawing the flatspade connectors from the back of the capacitor.• Replacement of the capacitor assembly is by thereversal of the above procedure.4.1.3 - Fan wiringFor any modifications of the wiring harness, refer to the fanwiring diagrams provided with the units.With the optional electrical box, three of the available fiveor six speeds of AC motor are connected - (maximum speed= R1, minimum speed = R5 for 42NH /R6 for 42NL).When the unit is delivered with an WTC or a NTC controller,for AC motor, three of the 5 or 6 speeds are connected.Speeds arrangement can be changed on site according tothe electrical diagram.WARNING: With the optional electric heater a minimumair flow must be maintained (see tables below).