Lennox CBX40UHV Series Unit Information page 40

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3. Configuring / Detecting Electric Heat Elements
RECOMMEND − USE FIGURE 11 AS A REFERENCE FOR SETTING JUMPER
CONFIGURATIONS ON THE AIR HANDLER CONTROL.
S
Set desired Heating Mode Blower Speed
jumper pin.
S
Electric heat is staged by room thermostat.
(AHC comes with factory jumper between
W1/W2 and W2/W3)
S
Refer to Air Handler Control Checkout flow
diagram for operation.
To enter Field Test Mode, push
and hold button next to 7−segment
LED display until dash symbol
(solid bar) appears, then release
button.
Solid dash
starts
blinking on
7−segment
display.
1.
AHC will start the indoor blower motor to the selected heat jumper speed setting and cycle the electric heat relays ON to automatically detect
number of electric heat elements. (Electric heat element may be wired to energize more than one element)
2.
AHC waits for maximum of ten seconds to detect electric heat 22 volt DC relay coils are energizing:
A.
If relay coil current is detected within ten seconds, AHC will show a 1 on the 7−segment LED display indicating that the first stage has
been detected. As each additional heat element is detected, 7−segment LED on the AHC will display that electric element number. (Ex-
ample: Last number displayed by the 7−segment LED is 3, the AHC is configured to operate three electric heat elements.)
B.
If relay coil current is not detected within ten seconds, the AHC will exit the test mode and resume operation with electric heat disabled.
3.
AHC will automatically exit Field Test Mode when configuration is completed. To verify that the number of electric elements detected
matches the installed electric heat package, the field MUST CONFIRM that the last number the 7−segment displayed before exiting the Con-
figuring/Detection Mode matches the number of installed electric heat elements. AHC stores the number of electric heat stages in non−volatile
memory.
4.
Verify that the indoor blower motor will continue to operate for an additional 30 seconds.
NOTE − If AHC push button is pushed or power is cycled on AHC is unable to verify all 22 volt DC electric heat relay(s) were energized using
electric heater detection, configuration will be stopped. Configuration function must be repeated.
IMPORTANT: All electric heat installations require the Air Handler Control (AHC) to be
manually configured to detect number of heat elements.
NOTE − All field replacement AHC will require configuring/detecting electric
heat elements.
Standard
Yes
_
Push and hold button until the solid H symbol is displayed on the
_
7−segment LED, then release button.
Figure 35. Configuring / Detecting Electric Heat Elements
Which Heat
Mode?
S
S
S
Configuration
S
AHC in Idle Mode
(No heating cooling or
indoor fan operation)
Turn room thermostat to OFF.
Finished
Page 40
EvenHeater
Set desired Heating Mode Blower Speed
jumper pin..
Install and wire discharge air temperature sensor.
Set desired Target Discharge Temperature
jumper pin. If jumper pin is missing or discharge
air temperature sensor is not detected, AHC
defaults to Standard Heat Mode. Target
settings are 85, 100, 115 and 130ºF)
Refer to EvenHeater Operation flow diagram for
operation.
No
H
CBX40UHV

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