furnace problem

[gdknapp]

main gas valve won't open to main burner. pilot is on but furnace won't start

[paul52446m]

main gas valve won't open to main burner. pilot is on but furnace won't start

Have you checked to see if you have 24 volts to the gas valve? Have you checked to see if you have 110 volts to furnace. If you do , check and see
if you have any 24 volt power any where
You could have no power to the furnace,bad transformer so no 24volt power.
If you have 24volts to gas valve and it doesn't open, then its bad
If your 110 to 24volt transformer is good so you have 24 volts, then you could
have a limit switch or roll out switch that is open. Do you have a 24volt or a millivolt gas valve? Later Paul