Nordyne O5LD-091A-12-R, Installation, Operation And Maintenance Manual

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16. Burner Primary (Safety) Control
The furnace is equipped with a primary combustion
control, sometimes referred to as the burner relay or
burner protector relay, which uses a light sensing
device (cad cell) located in the burner housing, to
monitor and control combustion. Over time, dust or
combustion residuals can build up on the lens of the
cad cell impairing its response to the flame. The cad
cell should be checked for cleanliness and proper
alignment if the primary control frequently shuts down
combustion.
7
ALL FURNACE CONTROLS ARE SENSITIVE
AND SHOULD NOT BE SUBJECTED TO
TAMPERING. IF PROBLEMS PERSIST, CALL
YOUR SERVICE CONTRACTOR.
17. COMBUSTION CHAMBER
This furnace is equipped with a high quality cerafelt
combustion chamber. It is held in place by a retaining
bracket.
CHECK THE ALIGNMENT OF THE
COMBUSTION CHAMBER AND OIL BURNER
BEFORE FIRING. IT IS POSSIBLE FOR THE
COMBUSTION CHAMBER TO SHIFT IF
SUBJECTED TO ROUGH HANDLING DURING
TRANSIT
.
The combustion chamber should be
inspected for damage or carbon build up whenever the
oil burner is removed for repairs or routine
maintenance.
DO NOT START THE BURNER UNLESS THE
BLOWER ACCESS DOOR IS SECURED IN
PLACE.
18. CIRCULATING AIR BLOWER
The O5LD-091A-12-R furnace model is equipped with
PSC motor Direct Drive blower systems. Direct drive
blower speed adjustments are not normally required in
properly sized extended plenum duct systems. The
motor RPM and air CFM delivery will vary
automatically to accommodate conditions within the
usual range of external static pressures typical of
residential duct systems. Under-sized duct systems
may require a higher blower speed to obtain a
reasonable system temperature rise. Some older duct
systems were not designed to provide static pressure.
They typically feature special reducing fittings at each
branch run and lack block ends on the trunk ducts.
This system may require modification to provide some
resistance to the airflow to prevent over-amping of the
direct drive blower motor. Selecting a lower blower
speed may correct this problem. Direct drive blower
speeds are adjusted by changing the "hot" wires to the
motor winding connections. Please refer to wiring
diagrams in Appendix B or the wiring diagram label
affixed to the furnace.
THE NEUTRAL WIRE
(normally the white wire) IS NEVER MOVED TO
ADJUST THE BLOWER SPEED
.
It is possible and acceptable to use a single blower
speed for both heating and cooling modes. The
simplest method to connect the wiring from both
modes is to use a "piggy-back connector"
accommodating both wires on a single motor tap. It is
also acceptable to connect the selected motor speed
with a pigtail joined to both heating and cooling speed
wires with a wire nut. As a safety precaution against
accidental disconnection of the wires by vibration, it is
advisable to secure the wire nut and wires with a few
wraps of electricians tape.
DO NOT CONNECT POWER LEADS
BETWEEN MOTOR SPEEDS. THE NEUTRAL
WIRE MUST ALWAYS BE CONNECTED TO
THE MOTOR'S DESIGNATED NEUTRAL
TERMINAL.
If the joining of the blower speed wiring is done in the
furnace junction box, tape off both ends of the unused
wire.
Do not use the blower speed wires as a source of
power to accessories as electronic air cleaners
and humidifier transformers.
The unused motor
taps auto-generate sufficiently high voltages to
damage accessory equipment.
DISCONNECT THE POWER SUPPLY TO THE
FURNACE BEFORE OPENING THE BLOWER
ACCESS DOOR TO SERVICE THE AIR
FILTER, FAN AND MOTOR. FAILURE TO
SHUT OFF POWER COULD ALLOW THE
BLOWER TO START UNEXPECTEDLY,
CREATING A RISK OF DEATH OR
PERSONAL INJURY.