1083293-UIM-D-1116
36
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 jumper on the control board to
give the desired airflow.
Do not move the motor wires to different positions on the
furnace control board!
The jumper has four positions, which will deliver sufficient airflow in
cooling mode for the cooling capacities shown in the table below. The
CFM delivery on each jumper position is shown in Table 17.
Continuous Fan Operation -
The airflow delivered by the furnace
during continuous fan operation can be adjusted as desired. This is
done my moving the FAN jumper on the control board to give the
desired airflow.
Do not move the motor wires to different positions on the
furnace control board!
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.
TAKING A FLUE GAS SAMPLE
If it becomes necessary to obtain a flue gas sample for analysis, it is
permissible to drill a small hole in the plastic flue pipe for a sample
probe, provided that the vent piping is PVC and the hole is properly
sealed afterwards. If using a polypropylene vent system, the vent sys-
tems manufacturer test port fitting must be used. DONOT drill a test
port hole in polypropylene piping. Use the following procedure:
1.
Drill a 11/32" hole in the side wall of the PVC vent pipe. If the hole is
in a horizontal section of the vent pipe, ensure that it is located
away from the bottom where condensation may be flowing back
toward the furnace.
2.
Operate the furnace a minimum of (10 minutes) to ensure stable
operation of the combustion process.
3.
Sample the flue gas as necessary to obtain CO readings.
4.
Using a 1/8" pipe tap, cut threads into the sampling hole of the PVC
pipe.
5.
Use high temp RTV as a sealant on the threads of a 1/8" brass
MPT plug and insert it 3 turns into the hole to correctly seal it.
TABLE 17:
Cooling Airflow - A/C Capacity in Tons
Models
Jumper Position
H
MH
ML
L
60/1200
3
2-1/2
2
1-1/2
80/1200
3
2-1/2
2
1-1/2
80/1600
4
3-1/2
3
2-1/2
100/1600
4
3-1/2
3
2-1/2
100/2000
5
4
3-1/2
3
120/2000
5
4
3-1/2
3
FIGURE 41:
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