Where do I get a technical manual for a Baxi Solo 3 PF gas boiler?

Boiler fires up for one minute then cuts out. It maybe at least five minutes before it fires up again for another minute. The Central Heating and water is only luke warm. The higher the temperature control on the boiler itself, the shorter the intervals for firing up.but still only fires up for one minute. I need a Manual for this boiler to diagnose the fault and for future reference.