Just got the tank filled. Well, topped off would be more accurate. 14 gallon tank took 5.5 gallons to fill. So take the 80% of capacity fill level (11.2 gallons) that means I was right around the half mark. The gauge on the tank showed just below half and the idiot lights inside showed nearly empty (kept flip flopping between 1 light and two).
I've about decided that the whole levels system is shot. Excluding the freshwater one. Time to order some seelevels I guess. But I'll move onto checking the furnace after work. I'm going to check voltage at the board and cycle it to see if I can see the sail valve move. I'll also check the voltage at the batteries.
Should I be getting a full 12v at the board?