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Electric Heat
The electric heating element is located behind the
indoor coil and consists of a three-bank heater
assembly. It has two thermal switches located
on top of the heater assembly; one cycling
(resettable) and one "One Shot" thermal switch.
Electric Heater Diagnosing
An indoor fan failure, outlet thermistor failure,
outlet temperature overheat condition, a
thermal
cut off (
TCO) failure, heater failure, board failure
and external thermostat wiring can cause a
heater not to turn on.
Check for Fault Codes
Check fault codes by pressing and holding
MODE
and then press
AUX
. Verify whether fault 1
(Inside fan fault), 3 (External thermostat wiring),
13 (Heater
airflow fault), 17 (Outlet thermistor
failure), 18 (Outlet temperature overheat) codes
are active. Record any other faults and clear the
codes by pressing
AUX
. Use corresponding fault
codes to diagnose other components as being
the electric heater fault condition.
Verify Electric Heater Operation
Enter Service Mode by pressing and holding
+
and
-
buttons. On entry, the display lights all
LED's. Press
MODE
until
EH
is shown in the
display. Pressing
+
turns the electric heater on
and pressing
-
will turn the electric heater off.
AUX
key exits Service Mode.
Verify Electric Heater Voltages
Verify electric heater voltages from the main
control. Heater banks are depended on breaker/
cord size (15A, 20A, 30A). While turning on the
heater in Service Mode, the main control will only
turn on the respective bank based off the power
cord installed. Use the active heater chart in the
next column to determine which heater bank will
be active.
Electric Heater
208/230 VAC 30 Amp Power Cord Installed
• Large Bank: J307 (
navy
) to K305 relay
(
brown
): 208/230 VAC
• Medium Bank: J308 (
brown
) to K305 relay
(
brown
): 208/230 VAC
• Small Bank: J310 (
yellow
) to K305 relay
(
brown
): 208/230 VAC
208/230 VAC 20 Amp Power Cord Installed
• Large Bank: J307 (
navy
) to K305 relay
(
brown
): 208/230 VAC
• Small Bank: J310 (
yellow
) to K305 relay
(
brown
): 208/230 VAC
208/230 VAC 15 Amp Power Cord Installed
• Large Bank: J307 (
navy
) to K305 relay
(
brown
): 208/230 VAC
265 VAC 30 Amp Power Cord Installed
• Large Bank: J307 (
navy
) to K305 relay
(
Orange
): 265 VAC
• Medium Bank: J308 (
brown
) to K305 relay
(
orange
): 265 VAC
• Small Bank: J310 (
yellow
) to K305 relay
(
orange
): 265 VAC
265 VAC 20 Amp Power Cord Installed
• Large Bank: J307 (
navy
) to K305 relay
(
orange
): 265 VAC
• Small Bank J310 (
yellow
) to K305 relay
(
orange
): 265 VAC
265 VAC 15 Amp Power Cord Installed
• Large Bank: J307 (
navy
) to K305 relay
(
orange
): 265 VAC
Active Heater
Coil Wattage (230V/265)
[208V]
Power Cord
Amp Size
2.45 kW [2.00 kW] Large Bank 15A, 20A, 30A
1.55 kW [1.27 kW] Medium
Bank
30A
1.00kW [0.82 kW] Small Bank
20A, 30A
(
Continued next page
)
