Atwood L.P. gas water heater spark ignition gas cutoff heat unit not working

NO.........

Thermal Cut OFF
A 'one time' fuse that blows at 190*F from blowback of flame out of combustion chamber. Blowback of flame would be due to an obstructed combustion/exhaust tube.
Safety device designed to shut down ALL DC power thereby completely shutting down the water heater.
IF it trips/blows...have to replace before water heater will operate again

T-stat
Normal temperature thermostat used to control water heater heating cycles.
Preset at to OPEN at 140*F
High temp set point is so that the small volume RV water heater can supply HOT water that is then tempered for use by mixing COLD water at faucet.
Brown wire from circuit board to t-stat then to thermal fuse then back on Brown wire to circuit board

ECO
Energy Cut Off (High Temp T-stat) Safety back up t-stat.
Preset to OPEN at 180*F
IF 't-stat' fails to OPEN at 140*F the ECO will OPEN at 1808F and shut down heating cycle.
IF the ECO OPENS is also locks out any further heating cycles until 'manually reset'
FAULT LIGHT (RED light on switch panel) comes on if ECO OPENS. Indicating a FAULT occurred. Will also come on if propane fails to light off.
To 'reset'-------turn ON/OFF switch OFF, wait 30 seconds then turn switch ON.


20-30 minutes heating is about normal recovery time for a 6 gallon water heater.
SO your water heater was probably getting close to stopping.

Straight HOT water at a faucet is NOT how to use RV hot water system.
Cold water first then HOT and then use cold to adjust temp for use

The water temps are set very high so don't assume it's bad. Try both Elec and
gas at the same time.