Mine has an overall power switch outside by the drain, which it will auto run in elec mode when plugged into 30amp. I can also run the gas at the same time ( for faster recovery) by hitting a swith in the inside control board. If there is not supplied electricity (30 amp), then i still have to turn on the outside power switch and hit the gas button inside.
Last weekend i had a problem where the hit water did not seem to be working in electric. (Began to think i had my first warranty issue). I noticed the reset buttons, hit those and turned on thas gas for a while, water gor hit. Turned off the gas and the water remained hot all weekend on electric.... yeah!!!!
Try a reset?
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