Reference - Controls - LG AR-DR12-05A Installation And Operation Manual

INDIRECT GAS FIRED FURNACES

Reference - Controls

Furnace Control with Microprocessor Control
If the unit is equipped with a microprocessor control, the expansion board acts as an interface between the microprocessor controller and the
furnace. In this case, the pCOe has no logic built into it since the logic is already contained in the microprocessor controller. On this type of
controller, the LED status lights show the following:
LED Color
Yellow
Red
Green
If the controller detects a fault, it will go into alarm mode and a message code will appear on the microprocessor controller. Message codes
that may appear include:
IG furnace no flame after three
trials
IG combustion fan high pressure
switch failure
IG furnace ignition control
Pressure switch closed with
combustion fan off
Combustion fan not proved
IG furnace max retry
High temp. alarm pressure fault
with excessive discharge temp.
Check for high limit trip
IG furnace offline
98
Status
Powered The pCOe has power.
The pCOe is not connected to the microprocessor controller. Check connection and the
Error
microprocessor controller power.
Operational The pCOe has power and is connected to the microprocessor controller.
Indicates a furnace failure to light or properly sense flame after 3 trials.
Indicates a call for high speed combustion fan but high pressure switch did not close.
Indicates an alarm from the ignition controller.
Indicates low pressure switch was closed with no call for combustion fan.
Indicates a call for low speed combustion fan but low pressure switch did not close.
Indicates that the max number of retries was reached.
Indicates upon a pressure fault, there was a high discharge temperature which could indicate a
high limit trip.
Indicates communication with furnace control has failed.
Due to our policy of continuous product innovation, some specifications may change without notification.
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Significance
Alarm Descriptions