1) No danger and gas flowing when the pilot does not lite, there is a flame sensor to stop it. No harm by using that red wall switch
2) Shut off the power and CAREFULLY unplug and replug in those 2 wire connectors on the gas valve. One is for the igniter and the other supplies power to the valve. That gas valve had a bad history of failures and may be the problem. There may be a red led on the circuit board which gives you an error code when the problem happens. The code is on the back of one of the furnace doors and may be the lower ones.
3) About a dozen problems can occur to cause your situation and you may really need an experienced Pro to fix it. Not something I can talk you thru and you need special tools to check the pressure switch etc.
2) Shut off the power and CAREFULLY unplug and replug in those 2 wire connectors on the gas valve. One is for the igniter and the other supplies power to the valve. That gas valve had a bad history of failures and may be the problem. There may be a red led on the circuit board which gives you an error code when the problem happens. The code is on the back of one of the furnace doors and may be the lower ones.
3) About a dozen problems can occur to cause your situation and you may really need an experienced Pro to fix it. Not something I can talk you thru and you need special tools to check the pressure switch etc.