All new propane tanks have a safety circuit in the bottle to shut off gas flow when a leak is detected. Opening the valve at the top of the tank too rapidly can trigger the valve to shut "mostly closed".
A leak, of course, can also trigger the safety shut off.
When the DSI Fault light comes on, does the flame on the burner go "low"?
The safety valve does not cut gas off completely; just "mostly."
Try closing both valves on your tanks; CRRRRRAAAAAACCCCKKKK the valve VERY slowly (like 10 seconds to open it 1/8th of a turn).
Light a burner in the stove and set it on high.
Light a couple more. My stove has 3 burners and I would run them all.
Watch the flame height carefully and have someone turn on the hot water heater. The DSI Fault light should come on as the water heater calls for heat. The stove burner flames should NOT go down.
After the water gets hot, the DSI Fault light should go out when the flame shuts off. This could take a while if the water was cold to start with.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW