I am happy to report I finally got my Excell on-demand water heater working. Sometime between a year ago when I first installed it (it worked perfectly) and earlier this month when we moved in, it decided not to ignite. I did everything – checked water pressure, replaced the batteries twice, cleaned the cold water filter, replaced the drain bulb screw (which I broke whilst tinkering), and finally called the Excell company in desperation. After walking me through all the possible causes for malfunction, they finally suggested I remove and clean the igniter magnet. It worked! Phew! Cristina and I finally took hot showers yesterday evening. Heaven.