I an not a professional plumber, I just do all the work around the house by necessity. 
Installation was straightforward and directions were easy to follow. I am sure it has been installed correctly. When first installed, it emitted blasts of hot water and air which is to be expected. This occurred even if the handle had not been engaged. This has occurred a couple of other times, it seems when a lot of hot water has been used by adjacent appliances. The pressure and flow of the unit is less than the model it replaced but is still adequate.