White Rodgers PS9 Up User Manual

269434-UUM-A-0407

Unitary Products Group

5

The motors in these furnaces are permanently lubricated, and do not
require periodic oiling.

SECTION II: SERVICE AND MAINTENANCE 

MANUAL

SAFETY SECTION

FURNACE MAINTENANCE SECTION

The furnace should be cleaned and adjusted by a certified dealer or
qualified service contractor once a year or before the start of every
heating season. The following items must be cleaned and serviced or
replaced if there are signs of deterioration.

1.

The vent terminal.

2.

The furnace vent and combustion air intake passageways. Should
it be necessary to service the vent/air intake system, the manufac-
turer recommends this service be conducted by a qualified service
agency. The operation of this appliance requires the reassembly
and resealing of the vent/air intake system.

3.

The furnace burners, ignitor and flame sensor.

4.

The condensate collection and disposal system. If any disassem-
bly of components containing flue or vent gases is required, a
qualified service agency must perform the service.

SEQUENCE OF OPERATION

The following describes the sequence of operation of the furnace. Refer
to Figure 1 for component location.

Cooling/heating thermostats have a fan switch that has an ON and
AUTO position. In the ON position the thermostat circuit is completed
between terminals R and G. The motor will operate on the speed tap
selected on the Continuous Fan speed Jumper on the control board (HI
COOL, LO COOL, or HEAT pins).

Cooling/heating thermostats have a fan switch that has an ON and
AUTO position. In the AUTO position the thermostat circuit is completed
between terminals R and G when there is a call for cooling. The motor
will operate on the speed tap wire that is connected to the HI COOL ter-
minal on the control board. When used with two-stage cooling units, the
motor will operate on the speed tap connected to the LO COOL terminal
when first stage cooling is operating. The motor will operate on the
speed tap connected to the HI COOL terminal when second stage cool-
ing is operating. The fan off setting is fixed at 60 seconds for SEER
enhancement.

When the thermostat switch is set on HEAT and the fan is set on AUTO,
and there is a call for heat, a circuit is completed between terminals R
and W of the thermostat. When the proper amount of combustion air is
being provided, the pressure switch will close, the ignition control pro-
vides a 17-second warm-up period, the gas valve then opens, the gas
starts to flow, ignition occurs and the flame sensor begins its sensing
function. The blower motor will energize 30 seconds after the gas valve
opens, if a flame is detected. Normal furnace operation will continue
until the thermostat circuit between R and W is opened, which causes
the ignition system and gas valve to de-energize and the burner flames
to be extinguished. The vent motor will operate for an additional 15 sec-
onds and the blower motor will operate for the amount of time set by the
fan-off delay jumper located on the control board. See Figure 6. The
heating cycle is complete, and ready for the start of the next heating
cycle.

ELECTRIC SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could result in
dangerous operation, serious injury, death or property
damage.
Improper servicing could result in dangerous operation,
serious injury, and death or property damage.
•

Before servicing, disconnect all electrical power to the fur-
nace. 

•

When servicing controls, label all wires prior to disconnect-
ing. Reconnect wires correctly. 

•

Verify proper operation after servicing.

 FIGURE 6: Furnace Control Board

FAN OFF
ADJUSTMENT
JUMPER

RED-LOW

YELLOW-MED. LOW

BLACK-HI

BLUE-MED. HI

CONTINUOUS
FAN SPEED
JUMPER