OEM thermal cut-off safety device for all Dometic and Atwood DSI (direct spark ignition) series RV water heaters. Positioned on the incoming power wire. Permanently breaks the circuit and shuts down the water heater if excessive heat is detected. Not resettable; must be replaced when tripped. Upgraded version with higher threshold than original 93866. Also known as Dometic part number 4471008518.
The Dometic 94398 is the OEM thermal cut-off (TCO) for all Dometic and Atwood DSI (direct spark ignition) series RV water heaters — a critical safety component that monitors the temperature in the burner area and permanently breaks the electrical circuit if excessive heat is detected. Also known as Dometic part number 4471008518. Replaces the earlier 93866.
The TCO is positioned inline on the incoming power wire to the thermostat and wired directly into the water heater's control circuit. If the burner area overheats — most commonly due to a blocked main burner tube or flue tube from spider webs, wasp nests, or debris — the TCO trips and permanently severs the circuit, shutting the water heater down before excessive heat can cause damage. Because it permanently breaks the circuit when tripped, it is not resettable or repairable and must be replaced. The upgraded 94398 has a higher temperature threshold than the original 93866, reducing nuisance trips from normal operation.
Fits all Dometic/Atwood electronic (DSI) water heater models, including: G6A-2E, G6A-3E, G6A-4E, G6A-6E, G6A-7E, G6A-8E, G9-EXT, G10-1E, G10-2E, G10-3E, G16-EXT, GC6A-7E, GC6AA-7E through GC6AA-10E, GC10A-2E through GC10A-4E, GCH6A-7E through GCH6A-10E, GCH10A-2E through GCH10A-4E, GE9-EXT, GE16-EXT, GH6-6E, GH6-7E, GH6-8E, WH-6GA, WH-6GEA, WH-9GEA, and others. If your Dometic/Atwood water heater is a DSI (electronic/direct spark ignition) model, the 94398 is the correct TCO.
The most common cause of TCO trips in DSI water heaters is a blocked burner tube or flue tube — spiders and wasps build nests in the small orifice during storage, restricting airflow and causing the flame to back up into the burner box, overheating the TCO. Before replacing the TCO: Inspect the burner tube and flue for blockages and clear them completely. Replace the TCO, then test. If the new TCO trips again quickly, the blockage or another overtemperature condition is still present. Replacing the TCO without clearing the blockage will just result in the new one tripping again.
The 94398 is the thermal cut-off for Dometic/Atwood DSI (electronic ignition) water heaters only. It is not for refrigerators. It is also not compatible with manual ignition (pilot light) water heater models. Confirm your water heater uses DSI ignition — look for "E" in the model number (e.g. G6A-7E) or "DSI" in the documentation.