Noob here, Goodman GMP075-3 . Vent kicks on, hear relays activate on circuit board, ignitor will not glow. Manually sucked on vent pressure switch hose to make sure diaphram is in, no results. Cut off both end of hose to ensure new tight fit with no pressure loss and reconnected, no change. Made sure all 4 flame roll out switches were pressed in (reset, but cannot test) with no change. Cleaned flame sensor with sandpaper (was not too discolored but saw on another thread) and reinstalled with no result.

Once cycle ends, LED on circuit board flashes red once apx every 3-4 seconds. If unplug and retry, cycle repeats itself but does not heat ignitor. No flame ever occurs.

Not sure if gas is kicking on with flow.

Any help is appreciated. Snowed here in Northern AZ last night and now this occurs, never happens when convenient, right.

Thanks.:confused:

Further info: Unplugged HSI and checked continuance. Shows open circuit even though I see no cracks. System operated last night when going to bed. Do you think I should take a chance and drive 20 miles to town and attempt to find a HSI before trying anything else. Flame sensors all appear okay and pushed in. Not sure they look when tripped. Pushed tops all down to make sure.

Getting cold in here, thanks

Yet more info: removed HSI. Some bright white spot and vertical crack that did not appear to go all of the way through element. Conitinuicy was all over board though. While testing, finished breaking. Element now in 2 pieces so must replace anyway. Appears to have been cracking for bit, can tell oninterior of element wher appears to be failing. On way to go buy another one. I assume if this has excessive resistance, it will keep start up cycle from continuing. I hope so...

I will check thread when I get back and update thread when back and HSI installed.

You already performed the troubleshooting and have your answer - faulty HSI. Check for voltage at ignitor connector during ignition trial to confirm. New ignitor will probably be different than original - pay attention to instructions.

Ok. Back. Thanks for info KC13. New replacement aftermarket HSI is installed and everything is now operating correctly. Appears to be cycling as designed. House is heating up again. Yay!

Hope this thread can help someone else out as well in the future.