Hello. I have a heatnglo gas fireplace (nat gas) that won't fire up (worked fine last season). It has the intellifire rc300 system for lighting the pilot and then the main burner once the pilot flame is detected. I am using this in non remote mode (i.e. the remote is not the issue). This is what I am seeing:

I turn the control module to on and the pilot lights. After a few seconds of flame detect, the sparking stops. At this point, the main burner should light but never does, however the control module beeps indicating all is well. The pilot will stay lit forever (until I turn the control module off).

I happen to have 2 fieplaces with the same rc300 controller. The other fireplace works as expected so I swapped the control module and the fireplace that was working is still working, and the one that isn't still does not, so I have ruled out the control module as an issue.

Per trouble shooting instructions I found online, I measured the gas valve voltage for the main burner and I get the expected 1.6 v to open the main valve, and then the 0.3 v to keep it open. I also ohmed out the solenoids for the pilot and main burner and both are within limits.

Any other ideas as what could be wrong? Anything else I could try?