Carrier 42NH - Removal procedure; COMPONENTS AND MAINTENANCE; Fan motor assembly

14
English
Level the unit (Figs. 7 and 8).
Adjust the hanger nuts so that the unit is inclined 0.5%
towards the condensate drain pan. In the other direction
(air ow direction) the unit must be perfectly level (Figs.7
and 8).
Condensate drain pipe (Fig. 9): Use a exible pipe with an
inside diameter of 16 mm and provide a constant fall of
20 mm/m over the whole horizontal pipe run. Install a 50
mm (minimum) siphon to prevent gases and odours from
owing back into the ceiling void.
WARNING: After drain pipe connection, control
clamping of the drain pipe and be sure there is no water
leakage.
If several units are connected to a common collector, a device
must be installed (Fig. 10). Before operating the unit, ensure
that the water ows into the internal condensate drain pan by
pouring some water into it. If problems are detected, check
the drain pipe slope and look for possible obstructions. In
all cases the connection duct(s) at the unit outlet must be
insulated to prevent any condensate formation on the walls.
NOTE: The pressure losses of these ducts must be compa-
tible with the unit performance. The duct must be as smooth
as possible. Avoid sharp bends. Check that there are no
leaks or kinks, and that there is no dirt or installation
debris inside the ducts. Debris within the ducts might
damage the fan wheel and the damper in the air diffusers.
When installation is complete - i.e. when the 42NH is
attached to the ceiling, air ducts are complete, water
mani-folds are in position with stop valves ready on the
connection stubs, and electrical installation is prepared -
then connect the water pipe (3/4’’ gas screw connector).
NOTE : Each fan-coil units shall be connected with
water exible pipes in order to avoid any damage due to
vibrations.
Ensure that a gasket (not supplied by Carrier) is installed
between the screw connector and the stop valve.
When all units are installed, open the stop valves on the
manifolds, bleed and then pressurize the circuits. To bleed
the coils, slightly loosen the bleed screws. The installation
can then be started.
NOTE: Do not switch on the power until all connections
are made and earthed.

Switch off the unit power supply at the isolator provided
for the purpose during installation (isolator not supplied
by Carrier).
• Disconnectthepowersupplyandconnectioncables.
• Closetheisolatingvalvesonthemanifolds.
• Disconnecttheexiblewaterpipesbyunscrewingthe
gas connectors.
WARNING: Since the exible water pipes do not have
drain valves, a receiver must be provided to allow the
cooling coil to be drained.
• Disconnect the supply air ducts.
• Disconnecttheexiblecondensatedrainpipe.Drain
the siphon into a suitable vessel.
• Supporttheunitlightlyandreleaseitbyunscrewing
the four nuts on the threaded hangers. Lower the unit
carefully.
COMPONENTS AND MAINTENANCE

4.1.1 - Fan assembly removal procedure
WARNING: Disconnect the power supply to the unit before
carrying out any work on the unit.
Identify and note the wired fan speeds. If the fan develops
a fault the whole assembly must be removed and replaced
(Fig. 11).
• Removethelter.
• 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(xedwithscrews)
to gain access to the maintenance screws of the panel
supporting the fan.
• Thefanassemblyanditspanelareheldinplaceby
four torx screws (T20). Remove these screws and slide
the assembly down.
• Removethefanmotorassembly.
NOTE: Be careful not to touch the fan blades during
the removal process to avoid unbalancing the fans.
• Forunitswiththeelectricheateroption,disconnect
the power supply cable to the heater. Withdraw the
cable through the cable gland.
• Unscrewtheelectricheaters.
• Replacementofthefanmotorassemblyisbythe
reversal of the above procedure.
WARNING: The electrical connections to the fan motor
must be made in accordance with the labels on the
connector block.
4.1.2 - Capacitor replacement procedure
• Disconnectthepowersupplytotheunitbeforecarrying
any work on the unit.
• Removethelter.
• Removethefanmotorassemblyaccesspanel.
• Removethecapacitorthatisattachedtothemotor
chassis assembly.
• Disconnectthecapacitorbywithdrawingtheatspade
connectors from the back of the capacitor.
• Replacementofthecapacitorassemblyisbythereversal
of the above procedure.