507335-01
Page 39 of 44
Issue 1624
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 (see page 31).
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 flash
codes are presented in Table 16.
Fault Code History Button
The control stores the last five fault codes in memory. A
pushbutton switch is located on the control (see Figure 42
on page 42). When the pushbutton switch is pressed and
released, the control flashes the stored fault codes. The
most recent fault code is flashed first; the oldest fault code
is flashed last. To clear the fault code history, press and
hold the pushbutton switch in for more than 5 seconds
before releasing.
High Heat State LED
On A80UH2V and 80G2UH-V models, a green LED is
provided on the control board to indicate high heat state
(see Table 17).
CFM LED
On A80UH2V and 80G2UH-V 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 flashes. Each flash signifies 100 CFM; count
the flashes and multiply by 100 to determine the actual CFM
delivered (for example: 10 flashes x 100 = 1000 CFM).
Failure Codes - Red LED
Table 16
High Heat State - Green LED
Table 17
Summary of Contents for 80G2UH-V
Page 29: ...507335 01 Page 29 of 44 Issue 1624 ADJUSTING AIRFLOW Table 11 ...
Page 41: ...507335 01 Page 41 of 44 Issue 1624 Wiring Diagram Figure 41 ...
Page 42: ...507335 01 Page 42 of 44 Issue 1624 Typical Field Wiring Diagram Figure 42 ...
Page 43: ...507335 01 Page 43 of 44 Issue 1624 Start Up Performance Check List UNIT SET UP ...
Page 44: ...507335 01 Page 44 of 44 Issue 1624 UNIT OPERATION ...