I have a noma programmable thermostat and I can't get the fan to come on independently of the heat. I have a two wire system

It will not do that on a two wire system. The blower will only come on in the heat mode

You posted in a different loction from your original post. But I am posting you answer here.

Two wires will only get you control over the heat with the furnace blower working automatically. You cannot control the blower unless you have more wires.