Installation Guide

507052-04 Page 41 of 53Issue 1727
Connect the desired speed tap to the “EAC” terminal and
the neutral tap to the neutral terminal on the ignition control
(refer to the furnace wiring diagram). The ignition control
will control the motor’s operation, including a nominal 20
second “on” delay with a call for heat and a nominal 180
second “off” delay when the thermostat is satised. It will
also operate the motor on a call for cooling, with no “on” or
“off” delays.
Verify that the unit is operating at the desired speed and
within the rise range as shown on the unit rating plate.
The correct replacement motor must be installed as soon
as possible to ensure continued satisfactory operation of
the furnace.
Control Diagnostics
Troubleshooting
Make the following visual checks before troubleshooting:
1. Check to see that the power to the furnace and the
integrated ignition/blower control board is ON.
2. The manual shutoff valves in the gas line to the furnace
must be open.
3. Make sure all wiring connections are secure.
4. Review the Sequence of Operation.
Start the system by setting thermostat above room
temperature. Observe system response. Then use the
information provided in this section to check the system
operation.
The furnace has a built-in, self-diagnostic capability. If a
system problem occurs, a fault code is shown by a red LED
on the control board. The control continuously monitors its
own operation and the operation of the system. If a failure
occurs, the LED will indicate the failure code. The ash
codes are presented in Table 12.
Fault Code History Button
The control stores the last ve fault codes in memory. A
push button switch is located on the control. When the
push button switch is pressed and released, the control
ashes the stored fault codes. The most recent fault code
is ashed rst; the oldest fault code is ashed last. To
clear the fault code history, press and hold the push button
switch in for more than 5 seconds before releasing.
High Heat State LED
On A95DF2V and 95G2DFV models, a green LED is
provided on the control board to indicate high heat state
(see Table 13).
CFM LED
On A95DF2V and 95G2DFV models equipped with a
variable speed motor, an amber LED is provided on the
control board to display CFM. To determine what CFM
the motor is delivering at any time, count the number of
times the amber LED ashes. Each ash signies 100
CFM; count the ashes and multiply by 100 to determine
the actual CFM delivered (for example: 10 ashes x 100 =
1000 CFM).
Table 12. Failure Codes - Red LED
LED Status Fault Description
LED Off
No power to control or control
hardware fault detected
LED On Normal operation
1 Flash Flame present with gas valve off
2 Flashes Pressure switch closed with inducer off
3 Flashes
Low-re pressure, rollout, or aux limit
switch open
4 Flashes High limit switch open
5 Flashes Not used
6 Flashes Pressure switch cycle lockout
7 Flashes Lockout due to no ignition
8 Flashes
Lockout due to too many ame
dropouts
9 Flashes Incorrect polarity and phasing
Table 13. High Heat State - Green LED
LED Status Description
LED Off No demand for high heat
LED On High heat demand, operating normally
LED Flashing
High heat demand, high pressure
switch not closed