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701379-UIM-C-0712
Johnson Controls Unitary Products 33
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.
VARIABLE SPEED MOTORS
The variable speed motor must be configured so the blower will provide
a sufficient airflow so that the furnace operates with in the temperature
rise range on the rating plate and within the application limitations
shown in Table 7 in these Instructions.
ADJUSTMENT OF FAN CONTROL SETTINGS
Heating Indoor Fan Off Delay
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 (60,
90, 120 and 180 seconds). The fan off delay is factory set to 120 sec-
onds. 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 41.
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 Table 7 “ELECTRICAL AND PERFORMANCE
DATA”.
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.
DANGER
FIGURE 42: Furnace Control Board
BLOWER OFF
DELAY JUMPER
HI HEAT DELAY
JUMPER
CONTINUOUS FAN
SPEED JUMPER
COOLING
PROFILE JUMPER
DEHUMIDISTAT
JUMPER
HEAT
PUMP
JUMPER
LOW VOLTAGE
TERMINALS
LAST
ERROR
CFM
STATUS
STAGING
180
120
90
60
OFF
10
15
20
SPEED
FAN
VS
HI
HI
LO
LO
NEUTRALS
Y1
Y2
Y
W1
W
W2
R
G
C
O
DHUM
X/L
YES
NO
HEAT PUMP
DHUM?
ADJ COOL
RELAY
HEAT
D
C
B
A
D
C
B
A
D
C
B
A
HUM
LINE
XFMR
EAC
BLOWER SPEED
JUMPERS