The ON/OFF switch (lower left corner outside compartment) is for the Electric Element. IF you did not turn that switch ON when you had no water the electric element will be OK.
The Switch inside 5vr is for the propane side. IF you turned it ON when you had no water......the propane probably fired off BUT tripped due to tank getting hot.
The RED light is a fault light....telling you that a trip has occurred and you need to reset.
Turn all switches OFF, in outside compartment above gas valve is a rubber cover with 'Push to Reset' buttons on cover.
Push them.......they reset high temp t-stats
Left side is for electric element & right side is for propane (if tripped you will feel them reset)
Water heater tank bypass valve closed...water in WH tank THEN turn on to heat
Good luck!
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31