Maintenance
RT-SVX34F-EN
99
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:
•
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 77, p. 103
. If operating pressures
indicate a refrigerant shortage, measure the system
superheat and system subcooling. For guidelines, refer to
“Charging by Subcooling”.
Note:
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
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. These bearing are considered
permanently lubricated for normal operation. For
severe dirty applications, if relubrication becomes
necessary, use a lithium based grease. See
Table 75,
p. 99
for recommended greases.
Note:
The bearings are manufactured using a special
synthetic lithium based grease designed for long
life and minimum relube intervals. Too much
lubrication in a bearing can be just as harmful as
not enough.
Use a hand grease gun to lubricate the 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.
•
YC* units only - Check the heat exchanger(s) for any
corrosion, cracks, or holes.
•
Check the combustion air blower for dirt. Clean as
necessary.
•
Open the main gas valve and apply power to the unit
heating section; then initiate a “Heat” test using the
startup procedure described in “Verifying Proper
Heater Operation”.
•
Verify that the ignition system operates properly.
Note:
Typically, it is not necessary to clean the gas
furnace. However, if cleaning does become
necessary, remove the burner plate from the front
of the heat exchanger to access the drum. Be sure
to replace the existing gaskets with new ones
before reinstalling the burner.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.
WARNING
Hazardous Gases and Flammable Vapors!
Exposure to hazardous gases from fuel substances have
been shown to cause cancer, birth defects or other
reproductive harm. Improper installation, adjustment,
alteration, service or use of this product could cause
flammable mixtures. To avoid hazardous gases and
flammable vapors follow proper installation and set up
of this product and all warnings as provided in this
manual. Failure to follow all instructions could result in
death or serious injury.
WARNING
Hazardous Pressures!
When using dry nitrogen cylinders for pressurizing
units for leak testing, always provide a pressure
regulator on the cylinder to prevent excessively high
unit pressures. Never pressurize unit above the
maximum recommended unit test pressure as specified
in applicable unit literature. Failure to properly regulate
pressure could result in a violent explosion, which
could result in death or serious injury or equipment or
property-only-damage.
Table 75. Grease recommendations
Recommended Grease
Recommended Operating
Range
Exxon Unirex #2
Mobil 532
-20 F to 250 F
Mobil SHC #220
Texaco Premium RB
