26 - DIAGNOSTIC CODES FOR STATUS LED
A RED LED is provided to indicate furnace operating status
LED Condition
Fault Condition
Check
LED ON
Normal operation
No action required. Control OK.
LED OFF
No power to control or
control
hardware fault detected
Line voltage input power at L1 and Neutral
connectors control board.
System wire harness in good condition and
securely connected at both ends.
1 Flash
High limit switch open
Open limit switch.
Limit switch and wiring in good condition and
securely connected.
Check for blocked air
fi
lter, correct temperature rise,
blower speed selection, closed ducts, ect.
2 Flashes
Pressure switches open
with inducer on
Pressure switches operation, tubing and wiring.
Obstruction or restrictions in venting preventing
proper air
fl
ow.
3 Flashes
Pressure switches closed
with inducer off
Pressure switches stuck closed.
Pressure switches mis-wired or jumpered.
4 Flashes
Control in 1 hour lockout
Gas supply OFF, or gas supply pressure too low to
operate furnace.
Damaged or broken HSI element.
Line voltage input power at L1 and Neutral
connectors control board.
Furnace not properly earth grounded.
Flame sensor rod contaminated or in incorrect
position.
HSI element located in wrong position.
Hot surface element or
fl
ame sensor wiring in good
condition and properly connected.
5 Flashes
L1/Neutral Polarity problem
Check supply voltage to ensure proper polarity to
L1 and Neutral connections.
6 Flashes
Not Used
7 Flashes
Pressure switch cycle
lockout
Pressure switches operation, tubing and wiring.
Obstruction or restrictions in venting preventing
proper air
fl
ow.
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