If you’re not getting gas to the burner on gas equipment, you can check several things in a process of elimination to determine what the problem is. First things first: check the gas regulator. Gas regulators are directional, which means gas will not flow if they are installed backwards. Check the arrow on the regulator and make sure it’s installed properly!
More often than not, the problem is the safety valve. Check out this Tech Talk post to learn how to identify and replace safety valves. Before you replace the safety valve, however, try
tapping on the valve and see if that gets gas to flow. Sometimes the plunger that blocks gas flow in the safety valve sticks and tapping on it will get it to move. This is an indication that your safety valve is going bad however, and will probably need to be replaced to soon.
Another possibility is that your thermostat is bad. There are two types of gas thermostats: BJWA and FDO type thermostats. BJWA thermostats are the most common type and older ones can be identified by the nickel sized hole on the front where the knob attaches. However, newer BJWA thermostats may not have that hole. FDO thermostats are usually found on pizza ovens and can be identified by the disc with numbers on it that sits behing the knob stem.