COACHMEN CATALINA 253RKS - Water Heater Thermostat Replacement

COACHMEN CATALINA 253RKS – Water Heater Thermostat Replacement

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Complete repair guide for the COACHMEN CATALINA 253RKS – Water Heater Thermostat Replacement.

Parts & Tools You’ll Need

Step 1: Diagnose Water Heater and Prepare Workspace

Start by turning off the water heater’s power at the breaker and closing the propane supply valve. Listen for clicking sounds from the thermostat or observe if the heater cycles on and off erratically—these are signs of thermostat failure. Drain the water tank completely by opening the drain valve at the bottom and allowing 10-15 minutes for full evacuation. Take photos of the existing wiring configuration before disconnecting anything, and verify that you have the correct replacement parts for your Coachmen Catalina 253RKS model.

Step 2: Remove Water Heater Access Door and Insulation

Locate the water heater compartment door on the exterior or interior wall of your RV, depending on your model configuration. Unscrew or unclip the door panel and carefully remove it, noting the foam seal orientation for reinstallation. You may need to remove or pull back some of the foam insulation around the water heater unit itself to access the thermostat housing. Set all removed components aside in a safe location where they won’t be damaged or lost during the repair process.

Step 3: Disconnect Thermostat Wiring and Thermal Sensor

Locate the existing Suburban 161109 thermostat or equivalent unit mounted on the side of the water heater tank. Carefully disconnect the wire connectors leading to the thermostat, labeling them with tape if your photos aren’t clear enough for reassembly. Use a wrench or socket to remove the thermostat from its mounting bracket—typically requiring 1/4″ or 3/8″ fasteners torqued to approximately 15-20 foot-pounds. Pull the thermal sensor (bulb) away from the tank wall gently, as these are often held in place with a simple clip or adhesive pad that may need slight warming to release safely.

Step 4: Install New Thermostat and Thermal Sensor

Position the new Suburban 161109 thermostat into the mounting bracket and secure it with the fasteners, tightening to 15-20 foot-pounds without over-tightening, which can crack the plastic housing. Ensure the thermal sensor bulb makes full contact with the water tank surface and sits flush against the metal—poor contact causes temperature reading errors. If using adhesive pads, clean the tank surface with isopropyl alcohol and allow to dry completely before applying the new sensor. Route the thermostat wires away from any sharp edges or hot surfaces, securing them with cable clips as needed.

Step 5: Replace ECO High-Limit and Heating Element

Locate the Atwood water heater ECO high-limit device, which is a safety component separate from the thermostat that prevents overheating. Disconnect its wires using the same labeling technique, then unscrew it from its mounting—this typically requires a 1-1/4″ wrench and torques to about 25-30 foot-pounds. Install the new ECO high-limit unit in the same position, ensuring the thermal sensor makes contact with the tank. For the 120V heating element, use the 1-1/16″ anode rod socket if the element is tank-mounted, or access it from the lower access port, replacing any damaged washers or gaskets in the process.

Step 6: Reconnect Wiring Using Proper Splice Connectors

Reconnect the thermostat wires to their labeled connections, ensuring each wire is fully inserted into its connector terminal. Use heat shrink wire splice connectors for any new connections required, applying heat with a heat gun until the shrink tubing bonds completely around the splice. Verify that no bare copper wire is exposed and all connections are mechanically sound by gently tugging each wire. Double-check against your photo documentation that every connection matches the original configuration before proceeding to reassemble the water heater compartment.

Step 7: Refill System and Verify Heating Operation

Close the drain valve completely and refill the water heater tank by turning on the fresh water supply, allowing air to vent from the pressure relief valve until water flows steadily. Wait 2-3 minutes for the tank to pressurize, then check all connections for leaks using a flashlight and dry cloth. Restore power at the breaker and the propane supply valve, then set the thermostat to 120°F and listen for the heating element to activate within 30-45 seconds. Allow the unit to run for at least 10-15 minutes, confirming that hot water reaches your tap and that the unit cycles off appropriately when the set temperature is reached, indicating successful thermostat calibration.