Manual Outdoor Air Damper; Economizer Adjustment; Evaporator Fan Service And Replacement; Evaporator Fan Belt Tension Adjustment - Carrier 50PG20-28 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

2. Cover area in tiontofthe unitservice panel withaterry
clothshop towel t oabsorb l ubricant spills andprevent
run-oft;. T owel wilt alsoprotect dropcloth f iomtears
caused bytools orcomponents.
3. Place t errycloth shop towel inside t he unitdirectly u nder
components tobeserviced toprevent spills through t he
bottom ofthe unit.
4. Perform t he required service.
5. Remove and dispose ofany oilcontalninated material per
local codes.
FANSHAFT BEARINGS Lubricate bearings atleast e v-
ery6 lnonths w ithsuitable bearing _ ease.
Typical lubricants
are _ven below:
MANUFACTURER LUBRICANT
Texaco Regal AFB-2*
Mobil Mobilptex EP No. 1
Sunoco Prestige 42
Texaco Multifak 2
*Preferred lubricant because it contains rust and oxidation inhibitors.
FAN MOTOR BEARINGS Fan motor bearings are of the
pennanently lubricated type. No field lubrication is required.
No lubrication of the condenser or evaporator lnotors are
required.
Manual Outdoor Air Damper-- If manual outdoor
air damper blade adjustment is required, refer to unit Installa-
tion Instructions.
Economizer Adjustment -- Ifeconolnizer adjustment
is required, refer to unit Installation Instructions.
Evaporator Fan Service and Replacement -- The
48/50PG units t_ature a slide-out fan deck tbr easy servicing of
the indoor-tan motor, pulleys, belt, and bearings. To service
components in this section, pertbnn the following procedure:
1. Turn offunit power.
2. Open the tan section access panel.
3. Remove three no. 10 screws at tiont of slide-out tan deck.
Save screws. See Fig. 38.
4. Disconnect the limit switch wires located on the right side
of the tan deck (48PG only). Other wires do not need to
be disconnected.
5. Fan deck can now be slid out to access serviceable
components.
DO NOT SLIDE FAN DECK OUT PAST THE STOP
BRACKET. If further access is required, the fan deck must
be supported. Make sure plugs and wiring are not pinched
between tan housing and unit center post. Damage to unit
may result.
6. To replace tan deck to operating position, slide Pan deck
back into the unit. Secure with the three no. 10 screws
relnoved in Step 3.
7. Re-attach electrical plugs and wires.
8. Close fan section access door.
9. Restore power to unit.
Evaporator Fan Performance Adjustment
(Fig. 38 and 39)
-- Fan motor pulleys are factory set
for speed shown in Table 57.
To change Panspeeds:
1. Shut offunit power supply.
2. Loosen nuts on the 4 can-iage bolts in the mounting base.
Using adjusting bolts and plate, slide motor and remove
belt.
3. Loosen movable-pulley flange setscrew (see Fig. 39).
4. Screw movable flange toward fixed flange to increase
speed and away fioln fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maxilnum speed specified in unit Installation
Instructions.
See Tables 27 and 28 for air quantity limits.
5. Set movable flange at nearest keyway of pulley hub and
tighten setscrew. (See Tables 33 and 34 for speed change
tbr each full turn of pulley flange.)
6. Replace and tighten belts (see Evaporator Fan Belt
Tension Adjustment section below).
7. Restore power to unit.
To align tan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide tan pulley along Panshaft.
3. Make angular alignment by loosening motor tioln
mounting plate.
MOTOR
FAN - PULLEY
PULLEY" (HIDDEN)
-MOTOR
LiMiT
SWITCH
Qt
CONNECT
(48PG ONLY)
MOUNTING
-BASE
SLIDE-OUT
FAN DECK
Fig. 38 -- Evaporator-Fan Motor Adjustment
PULLEY
PULLEY
STRAIGHTEDGE MUST
WITH BELT
MOTOR AND FAN
SHAFTS MUST BE
PARALLEL
MOVABLE
FLANGES
SETSCREWS_
FIXED FLANGES
SINGLE-GROOVE
Fig. 39 -- Evaporator-Fan Alignment and
Adjustment
87