Encountered this lovely configuration yesterday. People just purchased the home and needed to have the system winterized. Blew me away. It became obvious to me what happened. The installer put the system in without taking a pressure reading - 45 psi before RPZ. Then panicked and decided to throw a booster pump in so he can get paid. Booster does not even work and RPZ leaking. Provided an estimate for a new Pedrollo pump (INSIDE!) and a new RPZ. What a shame... system was well designed. Don't understand why this installer counldt finish the job properly.