32
SERVICE
Periodic Maintenance Checklist
Monthly
• Inspect air filter. Replace any filters.
• Inspect drain pan and clean if necessary.
Yearly
• Inspect and clean coils.
• Inspect fan wheels and housing for damage.
Ensure that wheels move freely by hand.
• Clean and tighten all electrical connections.
Preventing Excessive Condensation on Unit
Excessive condensation can be caused by running chilled water
through a unit with the unit fan off. If fan cycling is used, a water
flow control valve should be installed to shut off the water when
the fan stops.
Other methods of control which avoid condensation problems
are as follows:
1. If condensation is forming on the unit, verify the chilled
water valve is closing off tightly. Dirt or debris may pre-
vent the valve from closing completely.
2. Continuous fan operation with motorized chilled water
valve controlled by a thermostat.
3. Continuous fan operation with thermostat control to
switch fan from high to low speed (instead of off).
Check Drain
Check drain pan, drain line, and trap at start of each cooling sea-
son. A standard type pipe cleaner for
3
/
4
-in. ID pipe can be used
to be sure pipe is clear of obstruction so that condensate is car-
ried away. Check the drain line at filter cleaning time during the
cooling season. Be sure that debris has not fallen into unit
through supply air grille.
Fan Motor Bearings
Standard motors are permanent split capacitor, which are
equipped with permanently sealed and lubricated bearings. No
lubrication is required unless special motors have been supplied
or unusual operating conditions exist.
Fan Shaft Ball Bearing
The mid and inboard bearings are permanently sealed and lubri-
cated. No additional maintenance is required. The end bearings
must be lubricated at the start of each cooling and heating sea-
son. Add 5 to 10 drops of SAE 20 or 30 non-detergent based oil
to the bearing.
Clean Fan Wheel
For access to fan assembly, remove discharge grille (if supplied).
If unit is connected to ductwork, remove front (40UV) or bottom
(40UH) panel, separate fan shaft from motor at bushing, remove
motor, and slide fan assembly from track. Use a stiff brush or
vacuum to remove dirt and debris from scroll. Wipe all fan sur-
faces with a damp cloth. Reassemble as necessary.
Clean or Replace Air Filters
At the start of each cooling season and after each month of oper-
ation (more or less depending on operating conditions), replace
the throwaway filter or clean the permanent filter.
THROWAWAY FILTER
Replace filter with a good quality filter of the correct size. Do not
attempt to clean and reuse disposable filters. See Table 1 for fil-
ter sizes.
PERMANENT FILTER (FIBER TYPE)
1. Tap on solid surface to dislodge heavy particles.
2. Wash in hot water. If needed, use mild solution of com-
mercial solvent such as sal soda or trisodium phosphate.
3. Set filter on end so that water drains out through slots in
frame. Allow filter to dry thoroughly.
4. Recharge filter with recharging oil. Three ounces is suffi-
cient for a medium size filter. Oil may be applied by
insect spray gun. For easier spraying, the oil can be
warmed.
5. If the filter is dipped in the recharging oil, remove it
immediately and allow to drain through slots in frame.
6. Replace filter in unit.
If another type of filter is used, follow the filter manufacturer’s
instructions.
ECM Motor Removal and Re-installation
(see Fig. 24)
Carrier unit ventilators utilize an electronically commutated mo-
tor (ECM) to drive the indoor fan.
The ECM is a factory-programmed motor that is standard with
factory-supplied UV Open controls and units without factory-
supplied controls that are used in high-static applications or
high-capacity coils.
The ECM is programmed with an algorithm that maintains a
constant torque, as the static pressure on the system varies. For
example, as the filter pressure drop increases due to dirt, the fan
will increase speed (rpm) to maintain the cfm.
The ECM is identified by the two electrical receptacles located
on the housing. See Fig. 18-24.
The first receptacle is a 5-row in-line connector that feeds the
motor line voltage. This may be either 115 volts or 230 volts.
Units that are wired for 230 volts have a jumper between termi-
nals 1 and 2 on this plug (see wiring diagram).
The second receptacle on the motor is a 16-pin connector and is
used for speed switching. This is a low voltage (24-v) connec-
tion. There is a jumper wire between terminals 1 and 3. This is a
24-v ground. Voltage is present at all times when the motor is en-
ergized.
NOTE: A time delay exists between the time the motor speed is
switched and the motor’s reaction. This is designed into the elec-
tronics and
does not
indicate motor problems.
When replacing the motor, note the following:
• Check the part number of the old motor against that of
the replacement. There is a tag indicating the eight-digit
part number and begins with UVE. This is the program
number used for this motor.
CAUTION
Ensure that the unit is protected against freezing condi-
tions. If locking quadrant manual damper operator is pro-
vided, set to desired position. If damper actuator is
provided, ensure that actuator opens the damper when the
fan turns on, and closes when the fan stops.
WARNING
Lock out and tag all power supplies to equipment and con-
trols prior to servicing unit. Follow all safety codes. Failure
to do so could result in personal injury.
