As of 2016, VersaFlo Integrated Bypass Technology for JXi is available installed from the factory (select models) or as a retrofit to any Jandy Pro Series JXi pool and spa heater. The flow bypass valve is automatic and requires no external plumbing modifications. According to Zodiac, it offers up to 20 percent in additional energy savings when used with a variable-speed pump. Contact: Zodiac Pool Systems, (800) 822-7933;