Lennox ECB38 Series User manual

©2017 Lennox Industries Inc.
Dallas, Texas, USA
Page 1
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
WARNING
Electric Shock Hazard.
Can cause injury or death.
Foil-faced insulation has conductive
characteristics similar to metal. Be sure there
are no electrical connections within 1/2ʺ
of the insulation. If the foil-faced insulation
comes in contact with electrical voltage, the
foil could provide a path for current to pass
through to the outer metal cabinet. While
the current produced may not be enough to
trip existing electrical safety devices (e.g.,
fuses or circuit breakers), the current can be
enough to cause an electrical shock hazard
that could cause personal injury or death.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional HVAC installer or
equivalent, service agency, or the gas supplier.
INSTALLATION
INSTRUCTIONS
ELECTRIC HEAT SECTIONS
507805-01
12/2017
ECB38 Series Units
Shipping and Packing List
Package 1 of 1 contains:
1 – Assembled electric heat section
1 – Bag assembly containing the following:
Screws - 6 each
Wiring diagram - 1 each
Circuit breaker cover - 1 each
2 – Adhesive-backed foam seals
Check equipment for shipping damage; if found, immedi-
ately contact the last carrier.
WARNING
Electric shock hazard! - Disconnect all power
supplies before servicing.
Replace all parts and panels before
operating.
Failure to do so can result in death or
electrical shock.
ELECTRIC HEAT WILL NOT OPERATE
IF IT IS NOT CONFIGURED (SET UP)
THROUGH THE AIR HANDLER
CONTROL (AHC).
SEE CONFIGURATION PROCEDURE,
FIGURE 12 ON PAGE 9.
IMPORTANT INFORMATION FOR INSTALLER
H
H
CONFIGURE ELECTRIC HEAT
ECB38
®OR iComfort®S30 INSTALLER
SETUP, ELECTRIC HEAT MUST BE MANUALLY CONFIGURED.

Page 2
9-PIN
CONNECTOR
SECURING
SCREWS
AIR HANDLER
CONTROL
AIR HANDLER CONTROL
L-BRACKET MOUNTING PLATE
19 IN.
(483 MM)
5-1/2 IN.
(140 MM)
SENSOR
(CENTER SIDE-T0 -SIDE)
9-PIN CONNECTOR
ELECTRIC HEAT RELAY
LENNOX CATALOG #
49W91
22V DIRECT CURRENT COIL
30 AMP CONTACT RATING
FASTEN THE PROBE
BRACKET TO THE
PLENUM WITH TWO
SELF-TAPPING SHEET
METAL SCREWS.
CONNECT WIRES TO DISCHARGE AIR SENSOR
TERMINAL ON AIR HANDLER CONTROL.
PLENUM
CBA38MV AIR HANDLER CONTROL
LENNOX CATALOG # 16B27
DISCHARGE SENSOR (DAT)
TEMP RESISTANCE
ºF (OHMS)
30 34,566
40 26,106
50 19,904
60 15,313
70 11,884
80 9,298
90 7,332
100 5,826
DETAIL
A
NOTE - EVENHEAT MODE CANNOT BE ENABLED WITH
HARMONY IIIBECAUSE EACH CONTROL IS REQUIRED TO USE
ITS OWN DISCHARGE AIR SENSOR.
THE AIR HANDLER CONTROL (AHC) HAS
TWO SCREW TERMINALS MARKED
DISCHARGE AIR SENSOR. THE SENSOR
IS REQUIRED FOR EVENHEAT
OPERATION AND MUST BE ORDERED
SEPARATELY (CATALOG # 88K38) AND
FIELD-INSTALLED.
DETAIL B
DETAIL C
TEMPERATURE RESISTANCE
CHART
FIGURE 1. Component Connections

Page 3
Electric Heat Sections
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
The ECB38 series electric heat sections provide eld-in-
stalled electric heat for the CBA38MV series air handler
unit. ECB38 electric heat sections are available in sin-
gle-phase and three-phase voltages. Single-phase ECB38
heat sections are equipped with either terminal blocks or
circuit breakers.
General Information
These instructions are a general guide and do not su-
persede local codes. Local authorities having jurisdic-
tion should be consulted before installation. Read these
instructions thoroughly before starting installation. This
electric heat section and all other equipment used in the
HVAC system must be installed by a licensed profession-
al installer, or equivalent. You must follow federal, state,
and local codes while you install this or any other HVAC
equipment.
Be sure to disconnect all power to the unit before you in-
stall or service this equipment. Use proper tools and pro-
tective equipment during installation and service.
Installation of Lennox air handlers with or without optional
electric heat must conform with standards in the National
Fire Protection Association (NFPA) Standard for Instal-
lation of Air Conditioning and Ventilation Systems NFPA
No. 90A, and Standard for Installation of Resident Type
Warm Air Heating and Air Conditioning System, No. 90B,
the manufacturer’s installation instructions, and local mu-
nicipal building codes.
Heat Section Installation
Before installing the electric heat section, check the unit
rating plate to ensure that the unit meets the job require-
ments, that proper electrical power is available, and that
proper duct clearances are maintained.
NOTE - It is easier to install the ECB38 heat section inside
the air handler unit before the unit is set and the plenum
is attached.
1 - Shut off all power to the air handler. More than one
disconnect may be required.
2 - Remove air handler access panel.
3 - Disconnect and discard the 9-pin connector
currently attached to the air handler control.
4 - Loosen the two screws (see gure 1, detail A)
securing the air handler control L-bracket mounting
plate, and lift the plate off the screws. Pull the plate
forward and let it suspend in front of the unit to allow
access to the electric heat knockout.
CBA38MV
-018, -024, -030, -036, -042, -048, and -060
Measure the length and width of the backing plate of the electric heat
section to be installed in the air handler. Remove the appropriate
electric heat knockout in the air handler vestibule panel to match the
electric heat section being installed.
FIGURE 2. Air Handler Electric Heat Knockouts
5 - Remove the electric heat knockout from the air
handler vestibule panel to accommodate the heater
being used.
6 - Slide the electric heat section into the air handler
as illustrated in gure 3. Be careful that the heating
elements do not rub against the sheet metal opening
when they slide into the air handler. The hole(s) on
each side of the heater line up with holes in the air
handler control box. Secure the electric heater into
place with the screws that are provided in the bag
assembly.
ELECTRIC HEAT
KNOCKOUT SECTION
ELECTRIC HEAT
SECTION
FIGURE 3. Electric Heat Section Installation
7 - Reinstall the air handler control L-bracket mounting
plate by lifting it back in place. Tighten the two
screws to secure in place.
8 - Plug the 9-pin connector from the electric heat
section onto the air handler control 9-pin receptacle
as illustrated in gure 1, detail B.

Page 4
Circuit Breaker Installation
CIRCUIT BREAKER BRACKET
CIRCUIT BREAKERS
BLOWER DECK
PATCH PLATE
CIRCUIT BREAKER
SEAL
BLOWER ACCESS PANEL
BREAK AT THIS POINT
DISCARD
PATCH PLATE
FIGURE 4. Circuit Breaker Seal and Patch Plate Installation
ECB38-4CB, ECB38‐5CB,
ECB38-6CB, ECB38‐8CB,
ECB38‐9CB
ECB38‐12.5CB
ECB38‐15CB, ECB38‐20CB
ECB38‐25CB
ECB38‐8CB 3 Ph, ECB38‐10CB 3 Ph,
ECB38‐15CB 3 Ph ECB38‐20CB 3 Ph
ECB38‐25CB 3 Ph
DISCARD
BREAK AT THIS POINT
DISCARD
BREAK AT THIS POINT
ROTATE 180 AND
INSTALL OVER OPENING
ROTATE 180 AND
INSTALL OVER OPENING
LONG
SECTION
LONG
SECTION
PATCH PLATE SHOWN WITH LONGEST SECTION ON
THE RIGHT SIDE. PATCH PLATE MAY BE FACTORY
INSTALLED WITH LONG SECTION ON THE LEFT SIDE.
PATCH PLATE
(SHIPPED INSTALLED ON CB UNIT)
CIRCUIT BREAKER SEAL
(SHIPPED WITH ELECTRICAL HEAT AND
FIELD INSTALLED)
LONG
SECTION
DOTTED LINES ARE PERFORATIONS
SIDE OF UNIT
DISCARD
DISCARD
DISCARD
BREAK AT THIS POINT
BREAK AT THIS POINT
BREAK AT THIS POINT
SIDE OF UNIT SIDE OF UNIT
SIDE OF UNIT
SIDE OF UNIT
LONG
SECTION
LONG
SECTION
LONG
SECTION
FIGURE 5. Circuit Breaker Heater and Patch Plate Conguration (CBA38MV)

Page 5
1 - Install the circuit breaker on the air handler deck
ange as illustrated in gure 4. Use the provided six
screws to secure the circuit breaker.
NOTE - When applied in the downow position, the circuit
breakers must be rotated to the UP position. See gure 6
and follow the procedure below:
A - Disconnect power to the unit if present.
B - Remove the screw and slide the breakers off the
mounting rail.
NOTE - You may need to remove the wire tie closest to
the circuit breaker to allow rotation.
C - Rotate the circuit breaker 180º.
D - Slide the circuit breaker back on the rail and secure
in place with previously removed screw.
IN DOWNFLOW APPLICATIONS, CIRCUIT BREAKERS MUST BE
ROTATED 180 TO THE UP POSITION.
CIRCUIT BREAKER
MOUNTING SCREW
CIRCUIT BREAKER
BRACKET
CIRCUIT
BREAKERS
BLOWER
DECK
(REMOVE THE SCREW AND SLIDE THE
BREAKERS OFF MOUNTING RAIL.
ROTATE BREAKERS 180 AND SLIDE
BACK ON RAIL. SECURE WITH SCREW.)
NOTE - THE NUMBER OF CIRCUIT
BREAKERS USED IS DEPENDANT
ON THE SIZE OF THE ECB38 UNIT.
FIGURE 6. Typical Electric Heat Section
with Circuit Breakers
Circuit Breaker Cover Installation
If the air handler is installed in an unconditioned space,
the provided circuit breaker cover must be installed.
1 - Use isopropyl alcohol to clean the surface that the
circuit breaker cover will be attached to.
FIGURE 7. Circuit Breaker Location
2 - Remove paper backing from seal around perimeter
of circuit breaker cover (gure 8).
CIRCUIT BREAKER COVER (BACKSIDE)
REMOVE PAPER BACKING FROM FOAM SEAL
FIGURE 8. Remove Paper Backing
3 - Run a bead of clear silicone around the perimeter of
the circuit breaker cover to seal any gaps between
the cabinet access door and the circuit breaker
cover.
4 - Position the breaker cover over the air handler
circuit breaker opening (gure 9).
CIRCUIT BREAKER COVER
FIGURE 9. Circuit Breaker Cover Installation
IMPORTANT
Conrm air tight seal between breaker cover and air
handler access panel. Apply a thin silicone bead to the
adhesive back seat to ensure air tight seal.
Failure to seal circuit breaker cover will allow warm moist
air to be pulled into control panel which can create
condensation to form on the circuit breaker and other
electrical components within the control panel.
Discharge Air Temperature Sensor
The Air Handler Control (AHC) has two screw terminals
marked Discharge Air Sensor. The sensor is REQUIRED
for EVENHEAT operation, is eld-mounted and must be
ordered separately (Lennox Catalog # 88K38).
The air handler control reads the discharge air tempera-
ture sensor and initiates the following actions:
• In EVENHEAT mode the control turns ON or OFF the
electric heating elements during the heat demand to
maintain a specied temperature range at the discharge
air sensor.

Page 6
• Sends discharge temperature status message when
operating in EVENHEAT mode.
• Sends discharge air sensor temperatures to be dis-
played on the Air Handler Control when operating in
EVENHEAT mode
The discharge air sensor should be mounted downstream
of the electric heat elements and indoor air handler as il-
lustrated in gure 1, detail C. It must be placed in a lo-
cation with unobstructed airow, where other accessories
(such as humidiers, UV lights, etc.) will not interfere with
its accuracy
Electrical Connections
IMPORTANT
USE COPPER CONDUCTORS ONLY
NOTE - Refer to the nameplate on the air handler unit
for minimum circuit ampacity and maximum overcurrent
protection size.
The air handler units are provided with openings to be
used with 1-1/2 inch trade size (1-31/32 inch diameter)
conduit.
Select the proper supply circuit conductors in accordance
with tables 310-16 and 310-17 in the National Electric
Code, ANSI/NFPA No. 70 or tables 1 through 4 in the Ca-
nadian Electric Code, Part I, CSA Standard C22.1.
AIR HANDLER CONTROL 9-PIN CONNECTOR
Wiring connections between the air handler and the
ECB38 electric heat section are made with an eight wire
harness. See table 1 for wire designations.
TABLE 1. Electric Heat Connectors
Position Function / Description
1Heat stage 1 relay coil
2Heat stage 2 relay coil
3Relay coil return
4Heat stage 3 relay coil
5Heat stage 4 relay coil
6Heat stage 5 relay coil
7L1 230VAC supply from heater kit
8L2 230 VAC supply from heater kit
9Not Used
Unit Start-Up
1 - Use speed tap selection charts in tables 2 and 3 to
set air handler blower speed.
TABLE 2. Recommended Blower Speed Tap Selection
SPEED TAP SELECTION
BLOWER
COIL
COOL HEAT
AC HP
AC WITH
ELECTRIC
HEAT
HP WITH
ELECTRIC
HEAT
-018 COOL
PIN #2
COOL
PIN #2
HEAT
PIN #4
minus
HEAT
PIN #4
minus
-024 COOL
PIN #3
COOL
PIN #3
HEAT
PIN #4
minus
HEAT
PIN #4
minus
-030 COOL
PIN #3
COOL
PIN #3
HEAT
PIN #3
HEAT
PIN #3
-036 COOL
PIN #3
COOL
PIN #3
HEAT
PIN #3
HEAT
PIN #3
-042 COOL
PIN #3
COOL
PIN #3
HEAT
PIN #3
HEAT
PIN #3
-048 COOL
PIN #2
COOL
PIN #2
HEAT
PIN #2
HEAT
PIN #2
-060 COOL
PIN #3
COOL
PIN #3
HEAT
PIN #3
HEAT
PIN #3
TABLE 3. Recommended Blower Speed Tap Selection
MIX MATCH SPEED TAP SELECTION
BLOWER
COIL
COOL HEAT
AC HP
AC WITH
ELECTRIC
HEAT
HP WITH
ELECTRIC
HEAT
-042 with
2-ton HP
COOL
PIN #1
minus
COOL
PIN #1
minus
HEAT
PIN #1
minus
HEAT
PIN #1
minus
-048 with
3-ton HP
COOL
PIN #1
minus
COOL
PIN #1
minus
HEAT
PIN #1
minus
HEAT
PIN #1
minus
2 - Restore power to the unit with room thermostat set
to OFF.
3 - Unit can be congured in either Standard Heat or
EVENHEAT Mode. See Conguring/Detecting Heat
Section ow diagram on page 12 for set up.
4 - Afx the wiring diagram sticker to blower scroll
aligned with CB unit wiring diagram sticker.
5 - The air handler access panels are factory supplied,
and they have a patch plate over the circuit breaker
opening. Remove the circuit breaker patch plate
from the air handler access panel.
6 - Replace the air handler compartment access cover.
7 - Choose the appropriately sized adhesive-backed
circuit breaker seal and remove any perforated
sections (if needed). Apply the seal to the outside of
the air handler access panel so that the seal is snug
around the circuit breakers (see gure 4).
8 - Break the patch plate for the specic size of electric
heat unit / air handler unit that you are installing as
illustrated in gure 5. Discard the unused piece of
patch plate.
9 - Secure the patch plate on the air handler access door.
10 - Set the thermostat to desired setting.

Page 7
Conguring Unit
This section identies the requirements for conguring the air handler unit for unit size, heat mode selection, EVENHEAT
operation and Heat Pump/Cooling Operations.
Air Handler
Control Checkout
Power-up- Unit Size Code (Number or letter) displayed
represents unit size code (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).
AHC
recognizes
Unit Size
Code?
Electric
heat
Installed?
Finished
Which Heat
Mode?
Refer to EVENHEAT operation flow diagram, air handler or
ECB38 Electric Heat installation instructions.
W1 Call?
Ye sNo
Ye s
Standard EVENHEAT
Refer to Heat Pump or Cooling
Sequence of Operation flow
diagrams, Air Handler or ECB38
Electric Heat installation
instructions.
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 to W2 and W2 to W3.)
At the completion of each heat section demand (W1,
W2, and W3), the control board will immediately
de-energize the corresponding pilot relay(s).
At the completion of all heating demands, the indoor
blower will run for an additional 10 seconds before
de-energizing.
No
Ye s
NOTE - If the call for lower heat section is removed,
AHC will automatically de-energize higher heat
sections.
Indoor blower will immediately start to deliver CFM as
set by heating mode jumper on board with activation of
first electric heat pilot relay.
22 VDC pilot relays on board are energized one at a
time. There is a minimum of 10 seconds delay between
pilot relay activations.
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 ECB38 Electric Heat
installation
IMPORTANT: Field replacement controls
may need to be manually configured to
validate air handler unit size code.
Refer to Configuring Unit Size Codes flow
diagram, Air Handler or ECB38 Electric Heat
installation instructions.
ONE (H1)
H1
TWO (H1-H2)
H1
H2
H2
THREE
(H1-H3)
H1
H2
H3
FOUR (H1-H4)
H1 AND H2
H3
H4
FIVE (H1-H5)
H1 AND H2
H3 AND H4
H5
T-STAT CALL
W1
W2
W3
NUMBER OF HEAT SECTIONS DETECTED
NOTE - AHC will not recognize higher heat section
demand if lower heat demand is not present.
AIR HANDLER CONTROL (AHC)
PUSH
BUTTON
No (Display
Alarm Code 302)
SINGLE
CHARACTER
DISPLAY
FIGURE 10. Air Handler Control Checkout

Page 8
Configuring Unit Size Codes
(Model Number)
Power-up - Unit Size Code (number or letter)
displayed represents unit size code (air handler
model size and capacity). If three horizontal bars
display, Air Handler Control (AHC) does not
recognize unit size code (air handler model size and
capacity).
AHC in IDLE mode
(No heating, cooling or indoor fan
operation)
To enter unit size code
configuration, push and hold
button next to single character
display untildash symbol appears,
then release button.
Turn room thermostat
to OFF
Push and hold button until the solid
Psymbol is displayed on the single
character display, then release
button. This mode allows the user
to select a unit size code (number
or letter) that matches the air
handler model size and capacity.
Solid dash starts blinking
on single character
display.
Solid P starts
blinking on single
character display.
Push and hold button to allow AHC to display unit size
code (letter or number) for each different air handler
model for three seconds.
When the correct unit size code is displayed, release
button. Selected code will flash for 10 second period. During
that period, hold down push button until code stops blinking.
AHC will store code in memory and will automatically exit
the configuration and reset.
Verify that the selected unit size code is correct and
stored by cycling the 24 volt power to the AHC.
(During power-up of the AHC, the single character
display will show the stored unit size code. If three
horizontal bars display, AHC did not store the unit size
code. If this happens, configuration sequence must
be repeated.
Ye sNo
IMPORTANT: Field replacement controls may need to be
manually configured to validate air handler unit size code.
UNIT SIZE
CODE
A
C
E
F
H
Y
If ten second period expires or push button is held less than
three seconds, AHC will automatically exit configuration
and go into IDLE mode without storing unit size code. If this
happens, configuration sequence must be repeated.
.
AIR HANDLER CONTROL (AHC)
SINGLE
CHARACTER
DISPLAY
PUSH
BUTTON
AIR HANDLER
MODEL
CBA38MV-018/024
CBA38MV-030
CBA38MV-036
CBA38MV-042
CBA38MV-048
CBA38MV-060
FIGURE 11. Congure Unit Size Codes

Page 9
Heat Mode Selection -
Configuring / Detecting
Electric Heat Sections
IMPORTANT: All electric heat installations
require the Air Handler Control (AHC) to be
manually configured to detect number of heat
sections.
Which Heat
Mode?
Set desired Heating Mode Blower Speed jumper pin.
Electric heat is stages by room thermostat. (AHC
comes with factory jumper between W1/W2 and
W2/W3)
Refer to Air Handler Control Checkout flow diagram for
operation.
Configuration
Standard EVENHEAT
AHC in Idle Mode
(No heating cooling or
indoor fan operation)
To enter electric heat configuration,
push and hold button next to single
character display until dash symbol
(solid bar) appears, then release
button. Turn room thermostat to
OFF.
Ye s
Solid dash
starts
blinking on
single
character
display.
Push and hold button until the solid Hsymbol is displayed on the single character
display, then release button.
Finished
No
NOTE - All field replacement AHC will require
configuring/detecting electric heat sections.
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 EVENHEAT Operation flow diagram for
operation.
1AHC 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 sections. (Electric heat section may be wired to energize more than one element)
2AHC waits for maximum of ten seconds to detect electric heat 22 volt DC relay coils are energizing:
AIf relay coil current is detected within ten seconds, AHC will show a “1” on the single character display indicating that the first stage has been detected. As
each additional heat section is detected, single character display on the AHC will display that electric element number. (Example: Last number displayed by
the single character display is 3, the AHC is configured to operate three electric heat sections.)
BIf relay coil current is not detected within ten seconds,the AHC will exit the test mode and resume operation with electric heat disabled.
3AHC will automatically exit configuration when completed. To verify that the number of electric sections detected matches the installed electric heat package, the
field MUST CONFIRM that the last number the single character displayed before exiting the Configuring/Detection mode matches the number of installed electric
heat sections. AHC stores the number of electric heat stages in non-volatile memory.
4Verify 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.
AIR HANDLER CONTROL (AHC)
SINGLE CHARACTER
DISPLAY
PUSH BUTTON
FIGURE 12. Heat Mode Selection

Page 10
EVENHEAT Operation
INPUTS OUTPUTS
Room Thermostat Demand Target Discharge Air
Temperature Set at 85ºF
Target Discharge Air
Temperature Set at 100ºF
Target Discharge Air
Temperature Set at 115ºF/130ºF
Y1 Heat Pump First StageHeat Pump First Stage Heat Pump First + First Electric
Heat Section (H1)
Y1 + Y2 Heat Pump First and Second
Stage
Heat Pump First and Second Stage
+ First Electric Heat Section (H1)
Heat Pump First and Second Stage
+ First Electric Heat Section (H1) +
Second Electric Heat Section (H2)
if number of electric heater sections
detected is more than two.
Y1 + W1 and/or W2 Heat Pump First Stage + First
Electric Heat Section (H1)
tric Heat Section + Second Electric
Heat Section (H2) if number of
electric heater sections detected is
more than two.
tric Heat Section (H1) Second
tected is more than two.
Y1 and Y2 + W1 and/or W2
Heat Pump First and Second
Stage+ First Electric Heat Section
(H1)
Heat Pump First and Second Stage
ond Electric Heat Section (H2) if
number of electric heater sections
detected is more than two.
Heat Pump First and Second Stage
+ First Electric Heat Section (H1)
Second Electric Heat Section (H2)
if number of electric heater sections
detected is more than two.
W1 and/or W2 First Electric Heat Section (H1)
First Electric Heat Section (H1) +
Second Electric Heat Section (H2)
if number of electric heater sections
detected is more than two.
First Electric Heat Section (H1) +
Second Electric Heat Section (H2)
if number of electric heater sections
detected is more than two.
Heat pump first or second stage or electric heat demand will start the Air Handler
Control indoor blower at CFM value based on tables found in installation
instructions.
Heat Pump and electric heat
demand? Increase target discharge air temperature by 15Fº
Last room thermostat Heat
up- staging action
Timer delays for
120 seconds
Timer delays for 150
seconds
A
One Stage More than one stage
No
Yes
FIGURE 13. EVENHEAT Operation (1 of 2)

Page 11
Discharge air temperature is
within target range?
W call with one
Electric Heat
Section ON
More Electric
Heat
available
A
Measured
discharge air
temperature is
above or below
target range?
Electric heat ON
150 seconds if more than one stage is activated
or deactivated.
EVENHEAT Operation
Start Timer Delay
(Note 1)
Stop Delay Timer
Increase heat demand.
Y1 (with or without Y2) +
W1 and W2
Discharge air temperature sensor
setting on Air Handler Control will remain
at set point. W1 demand will increase set
point 15ºF. W2 demand will increase set
point an additional 15ºF. (Total of 30ºF)
Delay Timer
Finished or last
change was up-
stage
Delay Timer
Finished or last
change was
down-
stage
Above
Turn OFF Electric
Heat Section
Adjust Target
Discharge Air
Temperature
Turn ON one
Electric Heat
section
Adjust Target
Discharge Air
Temperature
NOTE - Optional Outdoor Thermostat
(Wired between R and W3) will lockout
electric elements 3, 4 and 5.
Y1 ON and
Y2 OFF
Activate Y2
Below
No
Ye s
Note 1 Activation delay
120 seconds if one heat stage is activated or deactivated
No
No
No
No
No
Ye s
Ye s
Ye s
Ye s
Ye s
Change in Heat
demand from
room thermostat?
Adjust Target Discharge Air
Temperature
Heat Pump OFF
Discharge air temperature sensor setting on
the Air Handler Control will remain at set point
on W1 demand and be increased 15ºF for W2
demand.
Heat Pump ON
FIGURE 14. EVENHEAT Operation (2 of 2)

Page 12
Electric Heat Wiring Diagram Cross Reference
The following table provides a cross-reference for diagrams for specic electric heat models.
TABLE 4
Electric Heat Section Model Wiring Diagram #
ECB38-4-5-6-4CB-5CB-6CB-P 537951-01
ECB38-8-9-8CB-9CB-P 537955-01
ECB38-12.5CB-15CB-P 537960-01
ECB38-20CB-P 537962-01
ECB38-25CB-P 537963-01
ECB38-8-10-15CB-Y 537964-01
ECB38-20CB25CB-Y 537957-01