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Important: The bearings are manufactured using a
special synthetic lithium-based grease
designed for long life and minimum relube
intervals. Over lubrication can be just as
harmful as not enough.
☐ Use a hand grease gun to lubricate these bearings; add
grease until a light bead appears all around the seal.
Do not over lubricate! After greasing the bearings,
check the setscrews to ensure that the shaft is held
securely to the bearings and fan wheels. Make sure
that all bearing braces are tight.
☐ Check the supply fan belt(s). If the belts are frayed or
worn, replace them. Refer to the
Adjustment," p. 175
for belt replacement and
adjustments.
☐ Check the condition of the gasket around the control
panel doors. These gaskets must fit correctly and be in
good condition to prevent water leakage.
☐ Verify that all wire terminal connections are tight.
☐ Remove any corrosion present on the exterior surfaces
of the unit and repaint these areas.
☐ Generally inspect the unit for unusual conditions (e.g.,
loose access panels, leaking piping connections, etc.)
☐ Make sure that all retaining screws are reinstalled in the
unit access panels once these checks are complete.
☐ With the unit running, check and record the following:
–
ambient temperature
–
compressor oil level (each circuit)
–
compressor suction and discharge pressures (each
circuit)
–
superheat and subcooling (each circuit)
Record this data on an "operator's maintenance log" like
the one shown in
Table 83, p.
pressures indicate a refrigerant shortage, measure the
system superheat and system subcooling. For guidelines,
refer to
"Charging by Subcooling ," p.
Important: Do not release refrigerant to the atmosphere! If
adding or removing refrigerant is required, the
service technician must comply with all
federal, state and local laws. Refer to general
service bulletin MSCU-SB-1 (latest edition).
Heating Season
WARNING
Hazardous Voltage!
Failure to disconnect power before servicing could
result in death or serious injury.
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Verify that no power is
present with a voltmeter.
RT-SVX073A-EN
"Fan Belt
188. If the operating
159.
Service and Maintenance
Before completing the following checks, turn the unit OFF
and lock the main power disconnect switch open.
☐ Inspect the unit air filters. If necessary, clean or replace
them.
☐ Check supply fan motor bearings; repair or replace the
motor as necessary.
☐ Check the fan shaft bearings for wear. Replace the
bearings as necessary.
Note: These bearing are considered permanently
lubricated for normal operation. For severe dirty
applications, if relubrication becomes necessary,
use a lithium based grease. See
174
for recommended greases.
Important: The bearings are manufactured using a
special synthetic lithium-based grease
designed for long life and minimum relube
intervals. Over lubrication can be just as
harmful as not enough.
☐ Use a hand grease gun to lubricate these bearings; add
grease until a light bead appears all around the seal.
Do not over lubricate!
☐ After greasing the bearings, check the setscrews to
ensure that the shaft is held securely. Make sure that all
bearing braces are tight.
☐ Inspect both the main unit control panel and heat
section control box for loose electrical components and
terminal connections, as well as damaged wire
insulation. Make any necessary repairs.
☐ Gas units only - Check the heat exchanger(s) for any
corrosion, cracks, or holes.
☐ Check the combustion air blower for dirt or blockage
from animals or insects. Clean as necessary.
Note: Typically, it is not necessary to clean the gas
furnace. However, if cleaning does become
necessary, remove the burner inspection plate
from the back of the heat exchanger to access
the drum. Be sure to replace the existing
gaskets with new ones before reinstalling the
inspection plate.
☐ Open the main gas valve and apply power to the unit
heating section; then initiate a "Heat" test using the
startup procedure described in
Table 73, p.
"," p.
160.
185
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