Configuring Unit Flow Charts; Air Handler Control (Ahc) Checkout - Lennox CBX40UHV Series Installation And Service Procedure

CONFIGURING UNIT FLOW CHARTS

1. Air Handler Control (AHC) Checkout

Power-up — Unit Size Code (Number or letter) displayed represents air handler model size and capacity. If
three horizontal bars displays, Air Handler Control (AHC) does not recognize unit size code (air handler
model size and capacity).
No
Finished
After all electric heat installations, AHC must be
manually configured to detect number of heat sections.
Refer to Configuring/Detecting electric heat sections
flow diagram, Air Handler or ECB40 Electric Heat
installation
No
Refer to Heat Pump or Cooling
Sequence of Operation
diagrams, Air Handler or ECB40
Electric Heat installation
instructions.
NUMBER OF HEAT SECTIONS DETECTED
T-STAT CALL ONE (H1) TWO (H1-H2)
W1 H1
W2
W3
A call for electric heating first, second or third stage is
initiated when 24 VAC (R) is detected on W1, W2 and W3
inputs on AHC. (Factory mounted metal jumpers connect
W1/2 and W2/W3.)
Indoor blower will immediately start to delivery CFM as
set by heating mode jumper on AHC with activation of
first electric heat pilot relay.
RECOMMEND — USE FIGURE 12 AS A REFERENCE FOR SETTING JUMPER CONFIGURATIONS ON THE AIR HANDLER CONTROL.
CBX40UHV
Air Handler Control Checkout
Electric heat
Installed?
Yes
Yes
Standard
W1 Call?
flow
Yes
THREE (H1-H3) FOUR (H1-H4)
H1 H1 H1 AND H2
H2 H2
H2 H3
Figure 33. Air Handler Control Checkout
AHC recognizes
No (Display
Unit Size Code? Alarm Code
203)
Refer to Configuring Unit Size Codes flow diagram, Air Handler or
ECB40 Electric Heat installation instructions.
IMPORTANT — Field replacement AHC may need to be manually
configured to validate air handler unit size code.
Which Heat
EVENHEAT
Mode?
Refer to EVENHEAT Operation flow diagram, Air Handler or
ECB40 Electric Heat installation instructions.
Pilot relays on AHC are energized one at a time. There
FIVE (H1-H5)
is a minimum of 10 seconds delay between pilot relay
H1 AND H2
activations.
H3 H3 AND H4
NOTE — AHC will not recognize higher heat sections
calls if lower heat section is not present.
H4 H5
At the completion of each heat section demand (W1,
W2, and W3), the AHC will immediately de-energize the
corresponding pilot relay(s).
NOTE - If the call for lower heat section is removed, AHC
will automatically de-energize higher heat sections.
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At the completion of all heating demands, the indoor
blower will run for an additional 10 seconds before
de-energizing.