5532522-UIM-B-0619
Johnson Controls Ducted Systems
17
ADJUSTMENT OF TEMPERATURE RISE
After about 5 minutes of operation, determine the furnace temperature
rise. Take readings of both the return air and the heated air in the ducts,
about six feet (1.83 m) from the furnace where they will not be affected
by radiant heat. Increase the blower speed to decrease the temperature
rise; decrease the blower speed to increase the rise.
This furnace has a standard ECM motor. The blower motor speed taps
are located on the furnace control board in the blower compartment.
Refer to Figure 18 and the unit wiring label to change the blower speed.
Place all unused motor leads on the PARK terminals. Two PARK termi-
nals are provided. To use the same speed tap for heating and cooling,
the terminals must be jumpered together. This control will change
blower speeds based on other 24V thermostat inputs (Y, W) respec-
tively.
ADJUSTMENT OF FAN CONTROL SETTINGS
This furnace is equipped with a time-on/time-off heating fan control. The
fan on delay is fixed at 30 seconds. The fan off delay has 4 settings (A =
60 seconds, B = 90 seconds, C = 120 seconds, D = 180 seconds). The
fan off delay is factory set to 120 seconds. The fan-off setting must be
long enough to adequately cool the furnace, but not so long that cold air
is blown into the heated space. The fan-off timing may be adjusted by
positioning the jumper on two of the four pins as shown in Figure 19.
The furnace is also equipped with a cooling fan on time delay. The cool-
ing fan on delay has two settings (A = 6 seconds, B = 24 seconds). The
cooling fan on delay may be adjusted by positioning the COOL jumper
as shown in Figure 18.
DANGER
The temperature rise, or temperature difference between the return
air and the supply (heated) air from the furnace, must be within the
range shown on the furnace rating plate and within the application
limitations shown in SECTION V.
The supply air temperature cannot exceed the
“Maximum Supply
Air Temperature”
specified in these instructions and on the furnace
rating plate. Under NO circumstances can the furnace be allowed to
operate above the Maximum Supply Air Temperature. Operating the
furnace above the Maximum Supply Air Temperature will cause pre-
mature heat exchanger failure, high levels of Carbon Monoxide, a fire
hazard, personal injury, property damage, and/or death.
!
FIGURE 19:
Furnace Control Board
DIAGNOSTIC
ERROR CODE
BUTTON
COOL BLOWER
ON JUMPER
HEAT BLOWER
OFF JUMPER
HUMIDIFIER
TERMINAL
ELECTRONIC AIR CLEANER
TERMINAL
3 AMP
FUSE
DIAGNOSTIC
LED
ID PLUG
A1104-001
