AAON RL-240 - Manual (Page 52)

52
Maintenance
(See back of the manual for maintenance
log)
At least once each year, a qualified service
technician should check out the unit. Fans,
evaporator coils and filters should be
inspected monthly.
Gas Heating
Make sure all gas supply lines have been
purged of air before turning on the electrical
power switch. Turn the gas valve to the on
position (see startup instructions). Turn the
main electrical power on and set the controls
to the heating mode of operation.
The combustion ventilation motor should
operate. The control will automatically
supply power to the igniter and the gas valve
after the heating call is made.
The flame sensing probe detects the
presence of the flame. Should no flame be
detected in 10 seconds, the ignition system
will recycle. If no flame is detected after 3
tries, ignition system will lockout.
The supply fans are controlled by the
ignition system. In the fan “Auto” mode the
fans come on 45 seconds after the flame is
proven and go off 120 seconds after the
cooling call is removed.
Furnace combustion ventilation air and flue
openings should be checked annually for
debris and obstructions. If vent extensions
are used they must meet category III
requirements.
The gas burner and heat exchanger should
never require cleaning. If cleaning is
necessary, this indicates faulty operation of
the unit. Cleaning should only be done by a
qualified service agency and only after
consultation
with an AAON service
representative.
If induced draft blower/motor assembly has
to be replaced, care must be taken to provide
an airtight seal between the blower housing
and the burner box.
Direct Fired Gas Heat
Direct fired burners mix gaseous fuel and
outside air to fire directly into the unit air
stream. Therefore, all available heat (minus
the heat of vaporization) is released directly
into the air stream. Optimal performance
demands that air velocities be uniform
across the entire burner. The profile plates
around the burner are adjustable to maintain
the required velocity. Adequate building
relief must be designed and incorporated
into the building. Non-recirculating units
(100% outside air) must not be connected to
any form of return duct. The outside air
must
be ducted directly outdoors.
Once a year, before the unit is in
operation for the heating season, a
qualified service technician should
inspect all flue product carrying areas
of the furnace and main burners for
continued safe operation.
WARNING
LEAK CHECK GAS PIPE
The gas pipe in the unit should be
checked for leaks before startup.
Leak checking is the responsibility of
the
installing contractor. All
connections should be checked for
leaks
annually after installation.
Failure to leak check could result in
fire, explosion, or other hazardous
situations.
DANGER