Product review (5 stars): This part is a replacement for original Whirlpool part 3403140
My Whirlpool gas dryer would not heat.  Ignitor would come on and go off but no flame.  Replaced the gas valve solenoids and I think it would have worked after that had I not forgotten to hook up the wires to the flame sensor.  An appliance parts guy told me to check the flame sensor for continuity before I replaced the gas valve solenoids.  I took off the two wires to the flame sensor and it checked out fine but I forgot to put the wires back on the flame sensor when I tested the dryer.  One of the loose wires for the flame sensor grounded out and then the ignitor did not work.  I checked the voltage going to the ignitor and there was no voltage (actually there was 13-17 volts...something like that) but there should be 120 volts going to the ignitor when the drying starts up and attempts to heat up.  Once I knew I was no longer getting current to the ignitor, I pulled off the wires on the two thermostats on the back of the dryer to check them for continuity.  One of the thermostats had continuity but the high limit thermostat did NOT have continuity at that point.

The dryer essentially uses one main circuit with multiple sensors/thermostats that will interrupt the circuit if there is a safety/heat problem.  Before replacing the high limit thermostat, I put a jumper wire between the two connectors that go to the high limit thermostat and everything worked with the jumper in place!  I suspect the short circuit caused by the loose flame sensor wire fried the high limit thermostat.  Anyway, I replaced the existing thermostat part number 3403140 with this part W10423382.  I was skeptical that this wasn't the correct part because this new part looks different and has a lower temperature rating. I researched online and found out that W10423392 is in fact the replacement for the original part 3403140.  I'm once again drying with gas!

If your dryer doesn't heat, you're somewhat handy with tools and have a multi-tester, there are a bunch of excellent youtube videos about how to isolate dryer problems and make repairs.  After I told one appliance repair guy that I shorted a wire in the dryer he said "the short could go anywhere and you need to get a new unit" (a new dryer!).  Since everything worked but the flame, I decided to troubleshoot further and I'm glad I did!  I spent about $60 total on parts at an appliance parts shop (it would have been less than half that much if I would have bought the parts on Amazon but I didn't want to wait) rather than $350-700 on a new dryer.  If your dryer is more than 20 years old, it might be time for a new one but a decent dryer should last a very long time.  The belt and idler pulley will eventually wear out but those can be replaced inexpensively and easily.  I replaced those about five years ago on my dryer when the belt started slipping and have not had any problems until the issue I just described with the flame not coming on.  Good luck!