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
Fault Code History Button
The control stores the last five fault codes in memory. A pushbutton switch is located on the control (see Figure 40 on page 38). 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 80G1UH2V models, a green LED is provided on the control board to indicate high heat state (see Table 14).
CFM LED
On A80UH2V and 80G1UH2V 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
| 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 |
| |
| 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 flame |
|
| dropouts |
| |
|
|
| |
|
|
|
|
| 9 Flashes | Incorrect polarity and phasing |
|
|
|
|
|
|
|
|
|
|
| Table 13 | |
High Heat State - Green LED
| LED | Description |
|
| Status |
| |
|
|
| |
|
|
|
|
| LED Off | No demand for high heat |
|
| LED On | High heat demand, operating |
|
| normally |
| |
|
|
| |
|
|
|
|
| LED Flashing | High heat demand, high pressure |
|
| switch not closed |
| |
|
|
| |
|
|
|
|
|
|
|
|
|
| Table 14 | |
Page 36 of 41 | Issue 1034 |
