When I try to start my furnace, the blower starts and the glow plug comes on but only two out of the four flame ports light. This is electronically lit, no pilot light... After about 30 seconds it kicks off, then will retry again, then will kick off again after the same situation happens. Then furnace will lockout due to retrys. ( 7 blinks )

Any thoughts would be appreciated!

Thanks in Advance.

If only two of the four burners are lighting, the flame sensor will not sense the flame, therefore it shuts the gas valve down. The flame senser is located at the opposite end of the burners than the glow plug. Now, we know what the problem is, and there are a few things that may need to be checked. THere is a cross igniter bar on the burner assembly that may need to be cleaned to allow gas to flow across, lighting all the burners. Also, incoming and manifold gas pressures need to be checked. If these things don't cure the problem, you need have to a professional in to check for a cracked heat exchanger (crossing my fingers that this isn't the problem).