Techs arrived shut off gas water and power to old unit removed unit from wall. A new navien model was installed in place of the old one. Minor movements of the water gas and electrical hook up to conform to new unit. Once unit was hooked up water was restored and tank and lines had been purged of air, prior to firing up new unit. Unit was tested for functionality and to ensure no leaks had been present. Customer was given the new units instructions and given a quick observation and instruction of the shut offs for the unit. Techs did not register unit on site, Casey said he will call in and register unit. New condensation pump recommended.