combi boiler?

I need to top up the pressure every few days on my combi boiler which is approx 2 years old, I have checked the discharge pipe for water and it does not appear to be that .So i guess I need to search for a leak, is there any way/ anything to do to make this an easy job or will i need to lift all the floorboards and check each pipe >

any thoughts/ideas would be welcome.
thanks