Carrier 50LJ008-014 - Manual (Page 15)

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To change fan speed;
1. Shut off unit power supply.
2. Loosen belt by loosening fan motor mounting plate nuts
(see Fig. 10).
3. Loosen movable pulley flange setscrew (see Fig 11)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed. In­
creasing fan speed increases load on motor. Do not ex­
ceed maximum speed specified in Table 1.
5. Set movable flange at nearest key way of pulley hub and
tighten setscrew (see Table 1 for speed change for each
full turn of pulley flange).
To align fan and motor pulleys;
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft
3 Make angular alignment by loosening motor from mount­
ing plate.
To adjust belt tension (see Fig. 10);
1, Loosen fan motor mounting nuts.
2. Slide motor mounting plate away from fan scroll for proper
belt tension (Vi-in. deflection with one finger) and tighten
mounting nuts. Tension can be applied using ‘/
2 -in. drive
—.......... 1 1 —r r ?_i: f.i "
MOTOR
.™Jli
Fig. 10 — Belt-Drive Motor Mounting
ratchet engaged into ‘/ 2 -in. square hole on motor mount­
ing plate.
3. Adjust bolt and nut on mounting plate to secure motor
in fixed position.
START-UP
IMPORTANT; Energize crankcase heaters 24 hours
prior to base unit start-up to remove entrapped refrig­
erant from oil. Heaters are energized as long as there
is power to unit.
Fig. 11 — Evaporator-Fan Pulley Adjustment
Unit Preparation — Make sure that unit has been in­
stalled in accordance with these installation instructions and
applicable codes.
Return-Air Filters — Make sure correct filters are in­
stalled in unit (see Table 1). Do not operate unit without
return-air filters.
Compressor Mounting — Compressors are inter­
nally spring mounted. Do not loosen or remove compressor
holddown bolts.
Internal Wiring — Check all electrical connections in
unit control boxes; tighten as required
Refrigerant Service Ports — Each refrigerant sys­
tem has 3 Schrader-type service gage ports; one on the suc­
tion line, one on the liquid line and one on the compressor
discharge line. Be sure that caps on the ports are tight.
Cooling — To start unit, turn on main power supply.
Set system selector switch at COOL position and fan switch
at AUTO, position. Adjust thermostat to a setting below
room temperature. Compressor starts on closure of
contactor.
Check unit charge. Refer to Refrigerant Charge section
on page 17.
Reset thermostat at a position above room temperature.
Compressor will shut off.
TO SHUT OFF UNIT — Set system selector switch at OFF
position Resetting thermostat at a position above room tem­
perature shuts unit off temporarily until space temperature
exceeds thermostat setting.
Heating (If Accessory Heater is Installed) — To
start unit, turn on main power supply.
Set thermostat at HEAT position and a setting above room
temperature, and set fan at AUTO, position.
First stage of thermostat energizes the first-stage electric
heater; second stage energizes second-stage electric heater
elements if installed. Check heating effects at air supply
grille(s)
If unit does not energize, reset limit switch (located on
evaporator-fan scroll) by pressing button located between
terminals on the switch.
TO SHUT OFF UNIT — Set system selector switch at OFF
position. Resetting heating selector lever below room tem­
perature will shut unit off temporarily until space tempera­
ture falls below thermostat setting
Safety Relief — A soft solder joint in the suction line
at the low-pressure service port provides pressure relief un­
der abnormal temperature and pressure conditions.
Ventilation (Continuous Fan) — Set fan and sys­
tem selector switches at ON and OFF positions, respec­
tively. Evaporator fan operates continuously to provide air
circulation.
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