Our recently purchased Ericson came with a demand hot water system. During our last trip with the boat, we ran out of water. After refilling the tank we could not get the water to flow through the hot water side. In reading the manual, it appears that there may be a flow switch that may stick and requires resetting when the heater is void of water. If offers two solutions. One, backflush the heater. Two, take the heater out and bang it against the bulkhead. Well, the first offer is worth attempting but seems like a tremendous effort for a simple problem like running out of water. Our heater is in a very restricted location. Even removing the cover plate requires the removal of the heater in order to reach the cover plate screws. Does anyone have another answer to resetting a sticky flow switch? And, could there be another reason that the hot water has stopped flowing?