Hi it will still need Bleeding through the pump. can you tell me if the burner has a red plastic cover held on with 2 small screws
I see your not online. so I will answer as if you do have that burner. Take off the 2 screws and remove the plastic shroud. on the left under the black control box is a hexaganol stem sticking out with an allen bolt in it. unscrew that allen bolt a quarter turn and attempt to fire the boiler. make sure you have a cloth under it and you leave the allen key in the bolt. when oil comes out of this which it will with force. nip it back up and you should be up and running. you may need to try a couple of times.
If you have an old Grant it will be the older burner so let me know. Its the same process but no stem or allen bolt just a nut. if you attempt it. Please Don't touch the flat screw on the pump this also sits within a nut/bolt affair. Good luck. Brian.