Service - Bryant 551A Installation, Start-Up And Service Instructions Manual

SERVICE

WARNING: Before performing service or mainte-
nance operations on unit, turn off main power switch to unit
and install lockout tag on disconnect switch. Turn off acces-
sory heater power switch if applicable. Electrical shock
could cause personal injury.
I. CLEANING
Inspect unit interior at beginning of each heating and cooling
season and as operating conditions require. Remove unit top
panel and/or side panels for access to unit interior.
A. Evaporator Coil
Clean as required with a commercial coil cleaner.
B. Condenser Coil
Clean condenser coil annually and as required by location
and outdoor-air conditions. Inspect coil monthly — clean as
required.
C. Condensate Drain
Check and clean each year at start of cooling season. In win-
ter, keep drains and trap dry.
D. Filters
Clean or replace at start of each heating and cooling season,
or more often if operating conditions require. Refer to Table 1
for type and size.
E. Outdoor-Air Inlet Screens
Clean screens with steam or hot water and a mild detergent.
Do not use throwaway filters in place of screens.
II. LUBRICATION
A. Compressors
Each compressor is charged with the correct amount of oil at
the factory. Conventional white oil (Sontext 200LT) is used.
White oil is compatible with 3GS oil, and 3GS oil may be
used if the addition of oil is required. See compressor name-
plate for original oil charge. A complete recharge should be
four ounces less than the original oil charge. When a com-
pressor is exchanged in the field it is possible that a major
portion of the oil from the replaced compressor may still be
in the system. While this will not affect the reliability of the
replacement compressor, the extra oil will add rotor drag and
increase power usage. To remove this excess oil, an access
valve may be added to the lower portion of the suction line at
the inlet of the compressor. The compressor should then be
run for 10 minutes, shut down, and the access valve opened
until no oil flows. This should be repeated twice to make sure
the proper oil level has been achieved.
B. Fan Shaft Bearings
For size 155 units, bearings are permanently lubricated. No
field lubrication is required. For size 180 and 240 units, the
bearings are of the pillow block type and have grease fit-
tings. The bearing opposite the motor end has an extended
tube line so it can be lubricated from the motor side. Lubri-
cate the bearings twice annually.
Typical lubricants are given below:
MANUFACTURER
Texaco
Mobil
Sunoco
Texaco
*Preferred lubricant because it contains rust and oxidation inhibitors.
LUBRICANT
Regal AFB-2*
Mobilplex EP No. 1
Prestige 42
Multifak 2
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C. Condenser and Evaporator-Fan Motor Bearings
The condenser and evaporator-fan motors have permanently
sealed bearings, so no field lubrication is necessary.
III. EVAPORATOR FAN PERFORMANCE ADJUSTMENT
(Fig. 30-32)
Fan motor pulleys are factory set for speed shown in Table 1.
To change fan speeds:
1. Shut off unit power supply.
2. a. Size 155 Only: Loosen belt by loosening fan motor
mounting plate nuts.
b. Size 180 and 240 Only: Loosen nuts on the 2 car-
riage bolts in the motor mounting base. Install
jacking bolt and plate under motor base (bolt and
plate are shipped in installer's packet). See Fig. 32.
Using bolt and plate, raise motor to top of slide and
remove belt. Secure motor in this position by tight-
ening the nuts on the carriage bolts.
3. Loosen movable-pulley flange setscrew (see Fig. 30).
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified in Table 1.
See Table 8 for air quantity limits.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew. (See Table 1 for speed change
for each full turn of pulley flange.)
6. Replace and tighten belts. See Belt Tension Adjust-
ment section on page 27.
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
mounting plate.
IV. EVAPORATOR FAN SERVICE AND REPLACEMENT
A. 551A155 Units (See Fig. 31)
NOTE: To remove belts only, follow Steps 1-6.
1. Remove filter and supply-air section panels.
2. Remove unit top panel.
3. Loosen carriage nuts A and B holding motor mount
assembly to fan scroll side plates.
4. Loosen screw C.
5. Rotate motor mount assembly (with motor attached)
as far as possible away from evaporator coil.
6. Remove belt.
7. Rotate motor mount assembly back past original
position toward evaporator coil.
8. Remove motor mounting nuts D and E (both sides).
9. Lift motor up through top of unit.
10. Reverse above procedure to reinstall motor.
11. Check and adjust belt tension as necessary.
B. 551A180,240 Units (See Fig. 32)
The 551A180,240 units use a fan motor mounting system
that features a slide-out motor mounting plate. To replace or
service the motor, slide out the bracket.
1. Remove the evaporator-fan access panel and the
heating control access panel.
2. Remove the center post (located between the evapora-
tor fan and heating control access panels) and all
screws securing it.
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