Along with dual venting options on interior units (RUC98i and RUC80i ), RUR98i and RUR98e come with integrated pump, internal bypass line, and thermal bypass valve and will work with either dedicated return line or crossover valve. Ultra Series RUR models do not require dedicated return line or complex system components. Also included, MC-195T digital controller lets user save on gas utility bills by scheduling multiple recirculation events throughout day to align with usage patterns.