Dometic Atwood 91873 Water Heater Thermostat & ECO – 110V AC

The Dometic Atwood 91873 Thermostat & ECO is a 110-volt AC temperature control and high-limit safety assembly used on many older Atwood electric and gas/electric RV water heaters. The thermostat regulates normal water temperature, while the ECO (Energy Cut-Off) provides over-temperature protection by shutting the electric heating circuit down if the water heater gets too hot.

The 91873 is a thermo-disc style thermostat/ECO assembly with high-limit control and is commonly found on legacy Atwood 6-gallon and 10-gallon water heaters equipped with 120V electric heating.

Models It Fits

The Dometic Atwood 91873 is listed for models including:

• GC6AA-7

• GC6AA-7P

• GC6AA-8

• GC6AA-8P

• GC10A-2

• GC10A-2P

• GC10-1

• GC10-2

• GC10-2P

• GCH6-4E

• GCH6A-7E

• GCH6A-8E

• GCH6A-9E

• GC6AA-7E

• GC6AA-8E

• GC6AA-9E

• GCH10A-2E

• GCH10A-3E

• GC10A-2E

• GC10A-3E

Additional legacy applications may exist, so always verify the water heater model and existing thermostat before ordering.

Replaces Dometic 92052

The 91873 is also listed as a replacement for Dometic/Atwood 92052 in applicable installations.

What the 91873 Thermostat & ECO Does

This assembly contains two important temperature-control functions:

• The thermostat controls normal electric water-heater temperature.

• The ECO/high-limit control shuts the system down if excessive temperature is detected.

Together, these components help control the 120V electric heating system and protect the water heater from overheating.

Signs & Symptoms of a Failed Thermostat or ECO

A failed 91873 may cause:

• Water heater does not heat on electric

• Electric heating element receives no power

• Water gets excessively hot

• Water heater shuts off prematurely

• Intermittent electric heating

• High-limit control repeatedly trips

• Thermostat or ECO fails continuity testing

Before replacing the thermostat assembly, verify the 120V power supply, electric heating element, wiring, switches, and circuit breaker.

Estimated Install Time

Approximately 20–40 minutes, depending on access to the rear of the water heater.

Tools Required

• Phillips screwdriver

• Multimeter

• Basic electrical hand tools

• Nut driver or socket set as required

Potential Issues

Disconnect 120V AC power before servicing the water heater.

A no-heat condition is not always caused by the thermostat. A burned-out heating element, failed switch, loose wiring connection, damaged junction box, or loss of 120V power can produce similar symptoms.

The 91873 is used on legacy Atwood/Dometic water heaters and should not be assumed to fit newer Dometic WH-series models.

Product Specifications

Manufacturer: Dometic / Atwood
Part Number: 91873
Replaces: 92052 in applicable installations
Part Type: Thermostat & ECO / High-Limit Control
Voltage: 110/120V AC
Style: Thermo Disc
High-Limit Control: Yes
Application: Legacy Atwood Electric and Gas/Electric RV Water Heaters

Important: Verify the complete Atwood water heater model number before ordering, especially on older GC, GCH, and GH-series heaters.