Suburban SW6P Water Heater Tank Replacement: Why You Need a Complete Unit

The Rundown

Unfortunately, you cannot replace just the tank on your Suburban SW6P pilot light water heater. The tank is permanently welded to the outer casing and is integral to the unit's structure and safety systems. When rust appears in your flushed water, it indicates internal tank corrosion that compromises the tank's integrity. Your only option is to replace the entire water heater unit, which typically costs between $400-600 for a new SW6P, plus installation time of about 2-3 hours.

The rust you're seeing after letting your RV sit indicates the tank's protective glass lining has failed, allowing the steel tank walls to corrode. This is actually a safety concern because continued corrosion can lead to tank failure and potential flooding. While it's disappointing given how much you love this unit, replacement is the safest and most reliable solution.

Why It Happens

The SW6P uses a glass-lined steel tank with a sacrificial anode rod to prevent corrosion. Over time, the glass lining develops microscopic cracks from thermal cycling - the repeated heating and cooling as you use the water heater. These cracks allow water to contact the steel tank directly, causing rust formation. The anode rod, which is designed to corrode instead of the tank, eventually depletes and can no longer protect the steel.

Sitting unused for extended periods actually accelerates this process. Stagnant water becomes more corrosive, and without regular flushing, sediment builds up and creates localized corrosion points. The pilot light models like your SW6P are particularly susceptible because they maintain constant low-level heat even when not actively heating water, which can stress the glass lining over time.

Additionally, water chemistry plays a major role. High mineral content, low pH, or high chlorine levels can accelerate both glass lining degradation and anode rod depletion. If you've been using your RV in areas with particularly hard or chemically treated water, this could explain why your beloved unit is showing rust earlier than expected.

Gather These Items

• New Suburban SW6P water heater (part number 5238A for LP gas model, around $450-550)
• New water heater gasket kit (part number 232767, about $15)
• Pipe thread sealant or Teflon tape for gas connections
• Basic hand tools: adjustable wrenches, screwdrivers, socket set
• Gas leak detector solution or electronic gas detector
• New flexible water supply lines if current ones are old or damaged
• Wire nuts and electrical tape for reconnecting 12V connections
• Shop vacuum for cleanup and debris removal

The Fix

Start by turning off the LP gas supply at the tank/source, then disconnecting the 12V power at the local disconnect or fuse, then at the RV's main panel if needed. Turn off the water pump and relieve system pressure by opening a faucet. Drain the old water heater completely by opening the drain plug and relief valve. Disconnect the hot and cold water lines, then carefully disconnect the gas line using two wrenches to avoid stressing the fittings. Remove the exterior access door and disconnect the gas control valve and any 12V wiring.

Remove the mounting screws that secure the unit to the RV's frame - typically four bolts accessible from inside the water heater compartment. The SW6P weighs approximately 45-50 pounds, so have someone help you slide it out of the compartment. Clean the mounting area thoroughly and inspect the compartment for any water damage from potential leaks.

Install the new unit in reverse order, ensuring all gaskets are properly positioned and connections are tight. Use pipe thread sealant on all gas fittings and test thoroughly for leaks using soapy water or gas detector before lighting the pilot. Verify proper venting and check for adequate combustion air supply to prevent carbon monoxide hazards. Fill the tank completely before attempting to light the pilot light, and follow Suburban's startup procedures exactly as outlined in the manual.

After installation, run the unit through several heating cycles and check all connections for leaks. Test both the pilot light operation and main burner function. Consider installing a water pressure regulator if you don't have one, as excessive pressure can stress the new tank and shorten its lifespan.

Know Your Limits

This replacement involves LP gas connections, which can be dangerous if done incorrectly. If you're not comfortable working with gas lines or lack experience with RV systems, hire a certified RV technician. Gas leaks can lead to fires or explosions, and many RV insurance policies require professional installation of gas appliances.

The electrical connections are straightforward 12V DC work, but the gas side requires proper tools and knowledge. Many RV service centers charge $100-150 for installation labor, which is reasonable considering the safety aspects and warranty protection you'll receive.

Consider this an opportunity to upgrade your maintenance routine for the new unit. Replace the anode rod annually, flush the tank every 3-6 months, and use a water softener if you frequently encounter hard water. With proper maintenance, your new SW6P should give you many years of reliable service just like your current unit has.