I went away for a couple of days and returned to a cold house. I have a Goodman Model HCC075ND4R that has Electronic Ignition with Relay + VR80204 - S8600H Control. I can not get it to fully ignite. It tries to ignite over and over again. I see a single blue flame for a short time, but not main burner kick-in. The fan does kick in on auto. I have replaced the batteries in the electronic T/C. Followed the manufacturer's instructions for resetting andmad sure that the gas line is open. Now what?

Try cleaning the flame sensor.

Thank you