Problem was flame wouldn't light, replaced bad ignitor and found another problem.
Original ignition control module: RobertShaw HS780/34NR-306A
1) Draft Inducer comes on
2) 34 sec ignitor warm-up
3) Gas valve receives 24 VAC and flame ignites
4) 6 second ignition proof starts
5) flame goes out, it doesn't see the flame
Cleaned flame sensor rod and burner, checked all wiring polarity - all OK
I have never taken the Micro-Amp readings from a flame sensor before so have no idea what range they should be in so did a bunch of research online and found good info on how to do and found that my meter is able to read Micro-Amps.
Found the attached PDF file online that explained what I need to know and gave some general specs.
If I check voltage on the flame sensor I get a good solid 119 Volts from flame sense terminal to ground and when checking for uA DC I get a good reading of 3.0 - 3.2uA DC -- I can't find any info on the RobertShaw controls as to what range of uA DC the flame sense circuit is looking for.
The general info I have found says these controls can run anything from .10 uA - 10 uA
I did find on one spec sheet for a RobertShaw control similar but not the exact same part of 1.5 uA which the 3.0 uA that I'm getting is well within the limits.
From everything I've done, (including running a ground wire directly from the module to the burner assembly), I conclude that the ignition modules flame sense circuit has failed and plan on replacing it with a S8910U1000 Honeywell ignition control module.
Would all the above sound like the ignition module is definitely my problem and does anyone have the actual specs of what the original control module uA DC reading should be.
Thanks for any help you can provide,