This is for gas fired
boilers only I will be adding oil fired soon.
How Do I Know, If it is my pump that is bad? This is not a simple question. because many things could be the cause of a pump not running. and there can be many other reasons that you don't have heat. This may be mush more then you should try to do on your own. Maybe you should call a Pro.
I'm just going to list some of the things that could be the problem. Every problem is unique and there is never a one reason answer for not having heat.