Replaces 7956-319, 7956-319P, 7990-318, 7990-318/A, 7990-318P, 7990-318P/A & 7990-319. 7990-319P
Diagnostic Flash Codes
Steady light on - normal operation.
One flash - ignition failure.
Two flashes - combustion air switch stuck closed.
Three flashes - combustion air switch failed to close.
Four flashes - limit switch open.
Five flashes - gas valve energized with no call for heat.
Rapid flashing - reversed polarity.
Note: Color of light is green.
The 2-minute video below illustrates how this board controls the operation of your furnace: