27
Induced Draft and Circulator Blower
Motors
The bearings in the induced draft blower and circulator blower
motors are permanently lubricated by the manufacturer. No
further lubrication is required. Check motor windings for
accumulation of dust which may cause overheating. Clean
as necessary.
Flame Sensor (Qualified Servicer Only)
Under some conditions, the fuel or air supply can create a
nearly invisible coating on the flame sensor. This coating acts
as an insulator causing a drop in the flame sense signal. If the
flame sense signal drops too low the furnace will not sense
flame and will lock out. The flame sensor should be carefully
cleaned by a qualified servicer using steel wool. The flame
sense signal should be 1 to 3 microamps.
Igniter (Qualified Servicer Only)
At room temperature, the igniter ohm reading should be from
20 - 100 ohms.
Burner
T
O
PREVENT
PERSONAL
INJURY
OR
DEATH
,
DO
NOT
REMOVE
ANY
INTERNAL
COMPARTMENT
COVERS
OR
ATTEMPT
ANY
ADJUSTMENT
.
E
LECTRICAL
COMPONENTS
ARE
CONTAINED
IN
BOTH
COMPARTMENTS
.
C
ONTACT
A
QUALIFIED
SERVICE
AGENT
AT
ONCE
IF
AN
ABNORMAL
OPERATION
SHOULD
DEVELOP
.
WARNING
The Ultra low NOx furnace uses a premix burner. The burner
box is sealed to achieve safe and reliable operation.
Cleaning (Qualified Servicer Only)
1. Shut off electric power and gas supply to the furnace.
2. Disconnect the rollout limit wires, flame sensor wire,
and disconnect the igniter plug.
L
ABEL
ALL
WIRES
PRIOR
TO
DISCONNECTION
WHEN
SERVICING
CONTROLS
. W
IRING
ERRORS
CAN
CAUSE
IMPROPER
AND
DANGEROUS
OPERATION
. V
ERIFY
PROPER
OPERATION
AFTER
SERVICING
.
CAUTION
3. Do not remove burner or other components.
4. Clean cabinet and around the inducer blower, moter
and burner box.
5. Reconnect wiring.
6. Turn on electric power and gas supply to the furnace.
7. Check furnace for proper operation. Refer to
“Operational Checks”
section to verify burner flame
characteristics.
Filters
T
O
AVOID
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
REMOVING
FILTERS
. N
EVER
OPERATE
FURNACE
WITHOUT
A
FILTER
INSTALLED
BECAUSE
DUST
AND
LINT
WILL
BUILD
UP
ON
INTERNAL
PARTS
RESULTING
IN
LOSS
OF
EFFICIENCY
,
EQUIPMENT
DAMAGE
AND
POSSIBLE
FIRE
.
WARNING
A return air filter is not supplied with this furnace; however,
there must be a means of filtering all of the return air. The
installer will supply filter(s) at the time of installation.
Filter Maintenance
Improper filter maintenance is the most common cause of
inadequate heating or cooling performance. Filters should
be cleaned (permanent) or replaced (disposable) every
two months or as required. When replacing filter, it must be
replaced with a filter of the same type and size.
Become familiar with filter location and procedures for removal,
cleaning and replacing them. If help is needed, contact the
installer of the furnace or a qualified servicer.
Filter Removal
HIGH VOLTAGE
!
T
O
PREVENT
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
DUE
TO
ELECTRICAL
SHOCK
,
DISCONNECT
ELECTRICAL
POWER
TO
THE
FURNACE
BEFORE
REMOVING
THE
FILTER
OR
PERFORMING
ANY
OTHER
MAINTENANCE
.
WARNING
Depending on the installation, differing filter arrangements
can be applied. Filters can be installed in either the central
return register or a side panel external filter rack (upflow
only). A media air filter or electronic air cleaner can be
used as an alternate filter. Follow the filter sizes given in
the Recommended Minimum Filter size table or instruction
provided by the media or electronic air cleaner manufacturer
to ensure proper unit performance.
To remove filters from an external filter rack in an upright upflow
installation, follow the directions provided with external filter
rack kit. For further details, see your distributor.
Horizontal Unit Filter Removal
Filters in horizontal installations are located in the central
return register or the ductwork near the furnace.
To remove:
1. Turn OFF electrical power to the furnace.
2. Remove filter(s) from the central return register or
ductwork.
3. Replace filter(s) by reversing the procedure for removal.
4. Turn ON electrical power to the furnace.
