The propane and 110 are separate and will operate on their own. The propane will heat up the water faster however. You can run both if you wish or just one, that's up to you. As for the water getting hot, once you use the 30 sec worth does it reheat and if so how long does that take. Check to make sure your water heater is getting filled. Maybe the bypass valves are not all turned the correct way. Open the out side door and with propane on watch and listen for the flame and how long it stays on.
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