Potterton Profile Boiler will not ignite. Possible Airlock?

We have a Potterton Profile 60e boiler. We have just replaced the central heating pump and turned everything back on. There are no airlocks in the water pipes and the water is flowing through the new central heating pump.
The problem we have now is that when we turned up the thermostat to fire up the Potterton boiler - it will not ignite.
If there is an airlock in the boiler, how do we bleed this? Where is the bleed valve situated on the boiler?