# 45465K005
Page 26
System Sentry™ 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
(beginning on
page 20).
Start the system by setting thermostat above room tempera-
ture. Observe the system response. Then use the informa-
tion 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 Tables 5 and 6.
Fault Code History Button
The control stores the last five fault codes in memory. A
pushbutton switch is located on the control (see unit
connection diagrams on page 28 and 30). 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 (G2D80CR and G2D80CT Models
Only)
On the two stage furnace models (G2D80CR and
G2D80CT), a green LED is provided to indicate high heat
state (see Table 7).
Failure Codes – Red LED
G1D80BR and G1D80BT Models
Table 5
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Failure Codes – Red LED
G2D80CR and G2D80CT Models
Table 6
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