PALOMINO PUMA 25RLSS - Water Heater Thermostat & Anode Rod Replacement

PALOMINO PUMA 25RLSS – Water Heater Thermostat & Anode Rod Replacement

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Complete repair guide for the PALOMINO PUMA 25RLSS – Water Heater Thermostat & Anode Rod Replacement.

Parts & Tools You’ll Need

Step 1: Diagnose and Prepare the Water Heater

Begin by identifying whether your water heater is producing lukewarm water, failing to heat entirely, or cycling on and off erratically—all signs pointing to thermostat failure. Turn off power to the water heater at your RV’s main breaker and allow the unit to cool for at least 2 hours. Locate the water heater access panel on the exterior of your Palomino Puma 25RLSS, typically found near the rear underbelly, and remove the covering by unscrewing the retaining bolts. Visually inspect the thermostat and ECO switch for any visible corrosion, water damage, or loose connections before proceeding with removal.

Step 2: Drain the Water Tank Completely

Close the main water inlet valve and open all hot water taps inside the RV to relieve pressure and allow air into the lines. Locate the drain plug at the bottom of the water heater tank and position a shallow pan underneath to catch residual water. Unscrew the drain plug by hand or with a wrench, allowing the tank to drain completely—this process typically takes 10-15 minutes. Once drained, use the Tank Rinser Flush Wand connected to a fresh water source to rinse out sediment and mineral deposits from the tank interior, spraying until clear water flows from the drain opening.

Step 3: Remove the Old Anode Rod Assembly

Locate the anode rod hex nut at the top of the water heater tank, which sits directly above the heating element area. Using the 1-1/16″ Anode Rod Removal Socket and a ratchet wrench, carefully apply steady downward pressure while turning counterclockwise—the connection typically requires 40-60 foot-pounds of torque to break free. Once loosened, unscrew the socket by hand and carefully extract the old anode rod, which will likely show significant corrosion with white or gray crusty deposits covering the magnesium or aluminum core. Inspect the threads inside the hex opening for damage; if threads are stripped, you’ll need a threaded repair insert kit before installing the new rod.

Step 4: Install the Replacement Anode Rod

Select either the Suburban Magnesium Anode Rod or Atwood Water Heater Anode Rod based on your water heater manufacturer’s specifications (check your serial plate or manual). Insert the new anode rod into the tank opening and hand-tighten the hex nut to finger-tight resistance, then use your removal socket and ratchet to tighten to 40-50 foot-pounds of torque. Avoid over-tightening, as excessive force can damage the tank’s internal threads or crack the rod itself. Wipe away any debris or sediment that escaped during installation with a clean cloth before reassembling the thermostat components.

Step 5: Replace the Thermostat and ECO Switch

Disconnect the electrical leads from the old thermostat by carefully unclipping the spade connectors (take a photo for reference or label with masking tape). Remove the mounting bracket bolts securing the thermostat to the tank wall, typically requiring a Phillips or flathead screwdriver, and slide the old unit away from the tank. Install the Suburban 161109 Water Heater Thermostat by positioning it against the tank surface and securing the mounting bracket with the original bolts—tighten snugly but not excessively. Reconnect the electrical spade connectors to the corresponding terminals on the new thermostat, then attach the Suburban Water Heater ECO Replacement switch in the same manner, verifying all connections are seated firmly with no exposed copper showing.

Step 6: Refill and Pressurize the Water System

Close the drain plug securely and hand-tighten it plus a quarter-turn with your wrench to create a water-tight seal without stripping the plug. Open the main water inlet valve slowly and allow water to fill the tank while simultaneously opening hot water taps inside the RV to purge air from the lines—this typically takes 5-10 minutes. You’ll know the tank is full when water flows continuously from the open taps without sputtering or air bursts. Turn off the interior taps once steady water flow is confirmed, then verify the drain plug area for any leaks by feeling the exterior surface with a dry cloth.

Step 7: Test System Operation and Verify Performance

Restore power to the water heater at the main breaker and set the thermostat to your desired temperature (typically 120°F for safety). Allow the heater 30-45 minutes to reach operating temperature, listening for the burner ignition sound and checking for any unusual odors or smoke. Turn on a hot water tap and verify that water temperature gradually increases over 20-30 minutes and maintains consistent heat without cycling on and off every few seconds. If the water temperature exceeds 130°F or fails to reach 110°F after an hour, or if the ECO switch trips repeatedly, power down immediately and recheck all electrical connections and the thermostat mounting position for proper tank contact.