1083292-UIM-A-0114
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Johnson Controls Unitary Products
ADJUSTMENT OF FAN CONTROL SETTINGS
Cooling -
The airflow delivered by the furnace during cooling operation
can be adjusted to match the cooling capacity of the A/C condensing
unit. This is done by moving the COOL and ADJ jumper on the control
board to give the desired airflow.
The COOL jumper has four positions, which will deliver the airflow in
cooling mode shown in Table 17.
The ADJ jumper has three positions which can be used to make further
adjustments to the cooling blower airflow.
Continuous Fan Operation -
The airflow delivered by the furnace dur-
ing continuous fan operation can be adjusted as desired. This is done
my moving the control fan jumper on the control board to give the
desired airflow.
The jumper has three positions. The “H” position delivers maximum air-
flow, 100% of the blower capacity. Position “M” delivers approximately
70% of the blower capacity. And Position “L” delivers minimum airflow,
approximately 40% of the blower capacity.
Delay Taps Selection
The set of jumper pins on the control board labeled “DELAY” are used
to set the delay profiles for the furnace. These can be chosen so as to
maximize the comfort and sound levels for various regions of the coun-
try.
Tap A
is the default profile. It provides a 30-second ramp-up from zero
airflow to full capacity and a 30-second ramp-down from full capacity
back to zero airflow. Whenever there is a change in airflow mode, such
as from low heat to high heat, the motor will take 30 seconds to ramp
from one speed to the other.
Tap B
is the humid profile. This profile is best-suited for installations
where the humidity is frequently very high during cooling season, such
as in the southern part of the country. On a call for cooling, the blower
will ramp up to 50% of full capacity and will stay there for two minutes,
then will ramp up to 82% of full capacity and will stay there for five min-
utes, and then will ramp up to full capacity, where it will stay until the
wall thermostat is satisfied. In every case, it will take the motor 30 sec-
onds to ramp from one speed to another.
Tap C
is the dry profile. This profile is best suited to parts of the country
where excessive humidity is not generally a problem, where the sum-
mer months are usually dry. On a call for cooling the motor will ramp up
to full capacity and will stay there until the thermostat is satisfied. At the
end of the cooling cycle, the blower will ramp down to 50% of full capac-
ity where it will stay for 60 seconds. Then it will ramp down to zero. In
every case, it will take the motor 30 seconds to ramp from one speed to
another.
Tap D
is the normal profile, best suited for most of the country, where
neither excessive humidity nor extremely dry conditions are the norm.
On a call for cooling, the motor will ramp up to 63% of full capacity and
will stay there for 90 seconds, then will ramp up to full capacity. At the
end of the cooling cycle, the motor will ramp down to 63% of full capac-
ity and will stay there for 30 seconds, then will ramp down to zero. In
every case, it will take the motor 30 seconds to ramp from one speed to
another.
Humidistat
When a humidistat is installed in the system, the “Humidistat con-
nected?” jumper on the control board should be moved to the “YES”
position. The cooling airflow will then be reduced by 15% whenever the
humidistat indicates high humidity.
FIGURE 46:
Furnace Control Board
Low
Voltage
Terminals
Humidistat
Jumper
Last
Error Button
Test
Button
Continuous
Fan Speed
Jumper
Cooling Speed
Jumper
Heat Pump
Jumper
Zoning
Jumper
EAC
Terminals
Humidifier
Terminals
Diagnostic
Light
