Scott, unless you nknow how to trouble-shoot printed circuit boards, the only way I know to test if it's good or bad is to pop a different board in (that's known to work - I just use a new one) and see if the heater fires up.

The boards are expensive. There is a chance that the Fenwall (ignition control) is bad, but the system is saying that it's the control board. Being able to check the possible problems saves you from having to buy a part that doesn't need replacing -- any chance you have a good friend with a similar heater who might be willing to lend you the parts so you can see which one you need to buy?