Annual Preventative Maintenance Inspection - Atwood 79 Series Service Manual

ANNUAL PREVENTATIVE MAINTENANCE INSPECTION

The following preventive maintenance and safety checks should be performed by a qualified RV technician
once a year, or more, depending on the use of the furnace. Failure to properly maintain the furnace may void
the furnace warranty and can result in unsafe furnace operation. Preventive maintenance is not covered
under warranty.
• Installation, repairs and preventative maintenance should be done by a qualified
service person only.
• The furnace should be inspected before use and at least annually by a qualified
service person.
• Frequent cleaning may be required due to excessive lint from carpeting, bedding
material, pet hair, etc. It is imperative that control compartments, burners and
circulating air passageways of the furnace be kept clean.
• Label all wires prior to disconnection when servicing. Wiring errors can cause
improper and dangerous operation. Verify proper operation after servicing.
AIR WHEEL
The air wheel should be clean and clear of
obstructions. Starting the furnace with something in the
blower will damage the wheel, making replacement
necessary.
BURNER
The Burner requires no adjustments, but should be
inspected annually. Burners should be cleaned with a
wire brush to remove debris and corrosion build up.
COMBUSTION CHAMBER
Check the air intake and flue areas of the furnace for
internal obstructions, such as wasp or bird nests. The
life of the combustion chamber is a function of the
amount of time that the furnace has operated.
Therefore, it is essential to inspect the chamber for
cracks and holes. Have the chamber replaced if it has
any cracks or holes - this condition is not field
repairable. Chamber should be cleaned if obstructions
are present, by removing the chamber and flushing the
unit out with water.
CONTROL COMPARTMENT
Clean the control compartment to remove dirt and lint.
DUCTING
The heat ducts should be clean and clear of
obstructions. Check for proper duct connection. Any
ducts disconnected from the furnace or outlets must
be reattached.
GAS PRESSURE
Using a U-tube water manometer, with the furnace and
all of the gas appliances operating, the pressure should
be 11˝ W.C. (27mbar). Improper gas pressure can cause
the furnace to work inconsistently and create
unbalanced combustion.
GAS SUPPLY SYSTEM
Perform a pressure-drop test according to current ANSI
standards, to insure that there are no gas leaks.
WARNING
WARNING
GASKETS
Inspect all gaskets for tight seals. Do not reuse gaskets
- always replace with new.
GENERAL
Check that the physical support of the furnace is sound
and without sagging, cracks, gaps, etc.
MOTOR
The motor is lubricated and permanently sealed. It
requires no oiling. Brushes and armatures are not
replaceable.
RETURN AIR
The return air passage should be clean and clear of
obstructions and meet the minimum square inches as
specified in the installation instructions. Make sure
combustibles are not stored in the furnace
compartment. Filters are not recommended at these air
passages.
VENTING
After checking and clearing, if necessary, the draft cap
assembly must have the proper overlap between the
exhaust tube and the furnace chamber tube. Any air
leakage at these joints may cause improper
combustion. Draft cap assembly must overlap no less
than 1-1/4˝ (32mm), and be positioned against the door
screen for proper function.
VOLTAGE
Voltage should be between 10.5 and 13.5 VDC at the
furnace during operation. The power at the furnace
needs to be checked with each of the following power
sources when applicable: generator, battery, and
converter. Low voltage can cause the furnace to
overheat and cycle. High voltage can cause
unbalanced combustion, and excessive motor wear.
Note: To increase motor life the furnace should be
wired directly to the battery.
WIRE CONNECTIONS
Check the furnace for loose or disconnected wires.
21