It's a VR8304 gas valve and S8600 ignition module. I found the following in a trouble shooting guide. It's not a millivolt system. It's over 15 years old also. The pilot is only on when it's energized.
How to check Gas Control Valve - Honeywell VR8304
The VR8304 gas control provides ON-OFF manual control of the gas flow. In the OFF position, the pilot
and main burner gas flow is prevented. In the ON position, pilot and main burner gas flow is under control of the
Honeywell 8600M electronic control module.
If main burner and or pilot will not light:
1. Check the gas control knob is in the ON position.
2. Verify the presence of a spark at the electrode assembly. You may need to recycle the heater by turning the
ON/OFF switch to OFF, waiting one minute and turning the switch back to ON. Also check the wiring harness
connections are clean and tight.
3. Adjust the thermostat to its highest setting to demand heat.
4. Using a multimeter check for 24 volts at the gas control:
a. If pilot lights, measure across the MV/PV and MV terminals (blue & white wires). If multimeter does
not register 24 volts, replace the ignition control module. If the multimeter registers 24 volts replace the gas control
valve.
b. If pilot DOES NOT light, measure across the MV/PV and PV terminals (brown and white). If
multimeter does not register 24 volts, replace the ignition control module. If the multimeter registers 24 volts
replace the gas control valve.