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MAIN BURNERS (48MP Only) —At the beginning of each
heating season, inspect for deterioration or blockage due to
corrosion or other causes. Observe the main burner flames.
Refer to Main Burners section on page 52.
FLUE GAS PASSAGEWAYS (48MP Only) — The flue col-
lector box and heat exchanger cells may be inspected by re-
moving heat exchanger access panel (Fig. 3 and 4), flue box
cover, and main burner assembly (Fig. 52). Refer to Main
Burners section on page 52 for burner removal sequence. If
cleaning is required, remove heat exchanger baffles and clean
tubes with a wire brush.
Use caution with ceramic heat exchanger baffles. When
installing retaining clip, be sure the center leg of the clip
extends inward toward baffle. See Fig. 53.
COMBUSTION-AIR BLOWERS (48MP Only) — Clean pe-
riodically to assure proper airflow and heating efficiency. In-
spect blower wheel every fall and periodically during heat-
ing season. For the first heating season, inspect blower wheel
bi-monthly to determine proper cleaning frequency.
To inspect blower wheel, remove heat exchanger access
panel. Shine a flashlight into opening to inspect wheel. If
cleaning is required, remove motor and wheel assembly by
removing screws holding motor mounting plate to top of com-
bustion fan housing (Fig. 54). The motor and wheel assem-
bly will slide up and out of the fan housing. Remove the
blower wheel from the motor shaft and clean with a deter-
gent or solvent. Replace motor and wheel assembly.
Lubrication
COMPRESSORS — Each compressor is correctly charged
at the factory. Refer to 06E Compressor Service Manuals if
additional information regarding compressor lubrication sys-
tem is required. See Compressor Oil section on page 29 and
Table 3.
FAN SHAFT BEARINGS — Lubricate fan shaft bearings at
least once a year with suitable bearing grease. Extended grease
lines are provided on pulley side of blower. Typical lubri-
cants are given below:
MANUFACTURER LUBRICANT
Texaco Regal AFB-2*
Mobil Mobilplex EP No. 1
Sunoco Prestige 42
Texaco Multifak 2
*Preferred lubricant because it contains rust and oxidation inhibitors.
FAN MOTOR BEARINGS — Thecondenser- and evaporator-
fan motors have sealed bearings so no field lubrication is
required.
DOOR HINGES — All door hinges should be lubricated at
least once a year.
Coil Cleaning — Clean the coils with a vacuum cleaner,
compressed air, water, or a non-wire bristle brush.
Refrigerant Circuit
LEAK TESTING — Units are shipped with a full operating
charge of R-22 (see Table 1). If there is no pressure in
the system, introduce enough nitrogen to search for the leak.
Repair the leak using good refrigeration practices.After leaks
are repaired, system must be evacuated and dehydrated
using methods described in GTAC II, Module 4, System
Dehydration.
REFRIGERANT CHARGE (Refer to Table 1) — At the liq-
uid line connection point on each circuit is a factory-
installed liquid line service valve. On each valve is a
1
⁄
4
-in.
Schrader connection for charging liquid refrigerant.
All units are shipped with a complete operating charge of
R-22. See unit nameplate and Table 1 for amount of charge.
When adding a complete charge, evacuate system using stand-
ard evacuating procedures and weigh in the specified amount
of charge. All units have charging charts for each refrigerant
circuit. See Fig. 55-59.
Fig. 52 — Burner Section Detail
CERAMIC
BAFFLE
CLIP
HEAT EXCHANGER
TUBES
NOTE: One baffle and clip wll be in each upper tube of the heat
exchanger.
Fig. 53 — Removing Heat Exchanger Ceramic
Baffles and Clips
Fig. 54 — Combustion Blower Removal
47