5396714-BUM-C-0919
2
Johnson Controls Ducted Systems
SECTION II: OPERATING THE FURNACE
1. Ensure electrical power to the furnace is turned on at the household
service box.
2. Set the wall thermostat to the required temperature.
3. If the furnace is equipped with air conditioning, turn the system
switch located at the wall thermostat to HEAT to operate the furnace
in heating mode.
The interlock system usually contains a heat-cool switch that must be
turned to either HEAT or COOL to activate heating or cooling operation.
If an interlock system has not been provided, the electrical supply to the
furnace must be turned OFF at the household service box when the air
conditioner is being used. When operating the furnace, the electrical
supply to the air conditioner must be turned OFF.
SHUTTING OFF THE FURNACE
1. Turn the thermostat to its lowest setting.
2. For complete shut-down, turn off electrical power at the household
service box.
SECTION III: SEQUENCE OF
OPERATION
When the room thermostat calls for heat, 24 V power is supplied to the
heating element switches. As soon as the first heating element switch
closes, the blower starts and power is supplied to the first heating ele-
ment. Each additional element is staged on in successive intervals.
When the room thermostat demand is met and no more heat is
required, the elements sequence off in the reverse order and the blower
turns off.
LIMIT CONTROLS
Each element has an automatic limit switch that is wired into the circuit.
The limit switch shuts off power to that element if the heat exceeds the
allowed maximum heat.
BLOWER REMOVAL
To remove the blower from the furnace:
1. Turn off power at the household service box.
2. Turn the furnace circuit breakers OFF.
3. Disconnect the wiring to the blower and remove the two screws
holding the blower in place.
4. Slide the blower out from the front of the furnace. See Figure 1 or 2.
5. To reinstall the blower, slide the blower into the furnace, attach the
two screws to hold the blower in place, and reconnect the wiring.
WARNING
If you have an air conditioner that does not use the furnace blower
for air distribution and operates completely independent of the fur-
nace, the thermostat system must have an interlock to prevent the
furnace and air conditioner from operating at the same time. Such
operation could cause equipment damage, energy waste and over-
heating of the home.
NOTICE
Furnace will still operate if room temperature falls below thermostat
setting.
!
NOTICE
Only authorized service technicians should remove the blower.
FIGURE 1:
EBE Downflow Component Locations
FIGURE 2:
EUE Upflow Component Locations
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