KZ Durango – RV Water Heater Thermostat and Heating Element Replacement

KZ Durango – RV Water Heater Thermostat and Heating Element Replacement

I’ve got my hand on a heating element that’s sitting loose in the tank—it spun out with barely any resistance, which tells me it’s been cycling on fumes for weeks. The rubber gasket came away brittle, almost crumbling, and when I test the element terminals with my multimeter, I get nothing but an overload reading. This is the job: a Durango owner parked here yesterday morning with no hot water, and after draining the tank and cracking open the water heater assembly, it’s clear both the element and the thermostat that controls it have checked out. This sits at that uncomfortable intersection where the work itself is straightforward—you’re turning wrenches and swapping parts—but the system you’re working with runs propane on one side and 120-volt AC on the other side simultaneously. Skip the insulation on a terminal connection or reinstall a drain plug dry, and you’ve turned a two-hour fix into a call to your insurance company. Walk through this methodically, respect the dual-fuel setup, and you’ll have hot water again before dinner. Rush it or cut corners, and you’re inviting real trouble.

Parts Needed:

• Suburban 232306 Thermostat Switch, Model: 232306, Outdoor&Repair Store (Part Number: 232306) ($18.99)
• Upgraded 520900 RV Water Heater Element For Suburban RV SW Series Electric Wa… (Part Number: 520900) ($17.00)
• Lrichy 110V/120V RV Water Heater Screw-In Electric Heating Element 110V/1400W… (Part Number: Replaces Suburban 520789/520900 • Atwood/Dometic 92249) ($21.97)
• VOTMELL 4 Rolls 1/2 Inch(W) X 520 Inches(L) Teflon Plumbers Tape,Pipe Sealing… ($3.59 ($0.90 / count))
• Nextronics Tool-Free Wire Connectors 25 Pieces – Quick Splice Terminal Blocks… ($8.99 ($0.36 / count))
• Suburban 232767 Water Heater Anode Rod (Part Number: 232767) ($25.99)

After years on the road, I’ve learned that the thermostat is almost always the first thing to fail on a Suburban water heater — and using anything other than an OEM replacement is a gamble I’m not willing to take. The Suburban 232306 Thermostat Switch is a direct factory replacement, which means no adapting, no splicing, and no second-guessing the wiring. It snaps in clean and calibrates correctly right out of the box — something knockoffs consistently fail to do.

I keep a spare heating element in my repair kit specifically because this failure always seems to happen when you’re three days from the nearest RV parts store. The Upgraded 520900 RV Water Heater Element for Suburban SW Series is built to match the original specs exactly, but with upgraded materials that hold up better against the mineral deposits and sediment buildup that kill stock elements prematurely. Just make sure you drain the tank fully and use a proper element wrench — rushing that step is how people crack the tank threads.

If you’re doing this repair on a tighter budget or your original element is no longer available, the Lrichy 110V/120V Screw-In Electric Heating Element is a solid universal option worth considering. At 1400W and designed specifically for RV water heater applications, it delivers reliable performance without the premium price tag. One thing I’ll flag from experience — confirm your thread size before installation and apply fresh PTFE tape to the threads every single time, no exceptions, or you’re just creating your next leak to chase down the highway.

Step 1: Testing and Removing Failed Components

Begin by verifying whether the heating element itself has actually failed. Make certain the power is switched off and the water tank has been fully drained before you touch anything. Disconnect one of the two power leads attached to the heating element’s terminal posts. Switch your multimeter dial to ohms (resistance measurement). Touch one probe to each terminal on the heating element and observe the reading. A functioning element will show resistance somewhere in the 8-15 ohm range, usually landing around 10-12 ohms on a standard RV unit. If your meter displays “OL” (which means open line/infinite resistance) or refuses to register a number, the element has internally failed and must be swapped out. Readings that drift far outside that 8-15 window also point to element failure.

Once you’ve confirmed the element is shot, unscrew it from the tank. Grab an appropriately sized wrench—most Durangos use 1-1/8″ or 1-1/16″ depending on the tank generation—and turn counterclockwise with steady, even pressure. Expect a small amount of water seepage when you first break the seal, even though you already drained it; the element sits below the waterline. The element will back out along with its rubber gasket seal. Take a close look at that old gasket—check for splits, permanent flattening, hardness, or visible cracks. Keep it nearby as a reference for the new one’s thickness and diameter. While you’re looking, scan the element itself for crusty mineral buildup, rust spots, or any visible fractures in the resistance coil, all of which confirm it needs replacing.

Next, evaluate the thermostat switch to see if it’s also reached the end of its service life. Locate the pair of thermostat units mounted near the heater’s upper section—you’ll spot one with a wider, flat conductor wire running to the propane circuit, and another with a thinner wire that feeds the 120-volt electric circuit. Zero in on the 120V thermostat if your electric heating isn’t working. Pop off the rubber cover that shields the reset button underneath. Look at the wiring terminals for heat discoloration, melted or charred insulation, blackened connector posts, or connections that have come partially loose. Unhook the two power wires that clip onto the thermostat’s lower terminals. Spin your multimeter to continuity mode or a low-resistance scale.

Touch the meter probes to the thermostat’s two contact points—continuity should show as zero or very close to zero ohms when the switch is at ambient temperature. If continuity is missing, or if you saw heat damage on the wires or terminals, the thermostat needs replacement.

Step 2: Installing New Components and Testing

Begin the heating element installation by prepping the threaded bore. Wipe out the tank opening thoroughly with a lint-free cloth, scrubbing away any leftover gasket material, mineral scale, or corrosion. A bit of gentle cleaner on the rag is fine. Take the replacement heating element and the fresh gasket that came with it (or buy one separately if it didn’t). Slide the gasket down onto the element’s threads until it seats flat against the element’s shoulder flange. Start threading the element into the tank opening by hand, spinning clockwise. Hand-tighten until you can’t turn it anymore without forcing it. Now pick up your wrench and give it one more turn—roughly 1/4 to 1/2 of a full rotation. Do not crank it down hard; over-tightening crushes the gasket or cracks the glass lining inside the tank.

The element should feel solid and immobile, with the gasket creating a leak-free seal all the way around. Now wire up the new element according to code. Find the two threaded posts sticking up from the new element. Take the hot conductor from your RV’s 120V circuit—usually black or red wire—and attach it to one post. Connect the neutral/ground wire—usually white or green—to the other post. Most elements don’t care which wire goes where, but match the original rig’s setup to be safe. Crimp on connectors or wire nuts that are rated for wet/outdoor conditions and tighten them securely. Wrap electrical tape around each connection to keep moisture out. Verify that no bare copper shows anywhere and that the connection points can’t accidentally touch the metal tank housing and short.

If you’re also swapping the thermostat, do it with care and precision. Unhook all of the wires attached to the old thermostat and remove the mounting bolts (typically two fasteners holding it to a bracket). Set the new thermostat in that exact same spot and angle—this positioning matters for accurate temperature sensing. Drive the mounting bolts home snug so it sits flush. Now reconnect the wires to the new thermostat’s terminals in the identical configuration they came from the old one. Snap a photo of the old unit before you disconnect it if you’re the least bit uncertain about wire routing. One terminal accepts the supply hot wire, and the other connects to the heating element’s power line. Tighten all connections. Snap the rubber protective cap back over the reset button. Now test everything before you call the job finished. Tighten down the water heater drain plug securely with your wrench. Crack open the RV’s freshwater supply valve and turn on a hot water tap inside the coach. Let water run until it flows without sputtering or bubbling—that confirms the tank filled completely and trapped air escaped.

Shut off the faucet and inspect the new element and all wire connections for any drips or wet spots. Switch on the circuit breaker feeding the water heater. Set your multimeter to AC volts and touch the probes to the heating element’s two terminals; you should see somewhere between 110 and 125 volts, ideally near 120V. Flip on the water heater switch at the interior control panel. Wait 30-45 minutes if it’s a 6-gallon tank, or 45-60 minutes for a 10-gallon unit, allowing the heater to climb to operating temperature. Run hot water at a faucet to verify everything works. Keep an eye and ear on that first heating cycle—listen for strange noises, sniff for burning smells, and check again for any leaks.

The Suburban 232306 Thermostat — Why This One Part Fixes the Temperature Swings Most Durangos Get

The Suburban 232306 thermostat is the piece that governs when your heating element turns on and off, and the moment it sticks or drifts out of calibration, you’re either burning your hands or showering in cold water while the heater does nothing. On KZ Durangos especially, this thermostat fails with such regularity that replacing just the element while leaving the original thermostat in place is basically guaranteeing you’ll be back under this same heater doing it again in half a year.

What works

• Fits KZ Durango and Suburban RV water heater assemblies without modification—no hunting for adapters or wrestling with mismatched threading on the mount.
• Water temperature becomes stable and predictable once again; your shower stays at one temp instead of cycling between scalding and tepid every few minutes.
• At roughly eighteen dollars, it’s cheap peace of mind—swap it whenever you’re replacing the element and you won’t have to disassemble this heater again next year when the thermostat finally gives up the ghost.

What doesn’t

• Aftermarket thermostat durability is hit-or-miss; some fail after eighteen months of use, which is why full-timers keep a spare stashed in the cabinet.
• You have to drain the tank and get inside the thermostat compartment to swap it—if access is corroded shut or mineral scale has calcified around the opening, you’re looking at two hours of wrestling instead of a quick fifteen-minute swap.

I second-guessed whether the thermostat was actually the culprit on my first KZ until I realized the element was getting full voltage but the tank never held temperature—swapped the thermostat and everything locked in solid. Get the Suburban 232306 thermostat here.

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