furnace will not ignite Rheem model number RCDA-075A-AR

[Hozer]

When I turn the thermostat up with the fan on auto I get nothing. The blower comes on when I turn the fan to on, the AC works (compressor comes on) on cool when the fan is on auto, but I get nothing on heat setting. I pulled the thermostat off an jumper-ed the red and white wires and get nothing. It is an older furnace that has a pilot light and it is lit. I blew out all of the orifices with compressed air, turned the gas valve off and then back on and re-lit the pilot light but get no noise or anything when I turn the thermostat on heat and the temperature up. Any guesses? what should I try next?

[Bobice]

The "Thermalcouple" which sits in the piolt generates minivoltage which energizes the solenoid on the gas valve allowing it to open. Change the thermalcouple (looks like a copper bulb with a tube going to the gas valve.

[Hozer]

A bad Thermalcouple was my first thought but the local appliance center said if the pilot lite is lit and working it should be fine. Please advise

[jb8103]

Check the voltage to the gas valve.