Grand Design Reflection – RV Water Heater Thermostat and Heating Element Replacement

Grand Design Reflection Water Heater Thermostat and Heating Element Replacement

Dealer service departments will tell you to swap the whole water heater assembly—$1,200 in parts plus labor that stretches across two days. Forum advice says the thermostat or heating element has probably just failed, and you can fix it yourself in an afternoon for under $200. One of those answers is costing you money you don’t need to spend. I’ve pulled up to enough Grand Design Reflections parked at holiday campgrounds to know which one is right: the dealers are wrong. The thermostat fails quietly, the heating element burns out from age, but the tank itself is fine. A family sitting in a cold rig because they took the dealer route at face value is something I see every season, and it’s preventable. This walkthrough covers what I actually do on-site—how to diagnose which component is dead, how to swap it without mistakes, and how to verify the repair stuck instead of just resetting until the next failure ruins another weekend.

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 using the exact OEM replacement part makes all the difference on a thermostat swap — and the Suburban 232306 Thermostat Switch is exactly that. It drops right into the Grand Design Reflection’s Suburban water heater without any adapter fussing. The contacts are clean and reliable, and the snap-in installation means you’re not wrestling with it in a cramped wet bay. Just make sure power is completely off before you touch those terminals — this is not a step to rush.

When my heating element finally gave up the ghost outside of Amarillo, I wished I’d had a spare already in the bay. The Upgraded 520900 Suburban SW Series Heating Element is a solid cross-compatible replacement that I now keep stocked. It’s built to match the original wattage and thread spec, so it seats flush with a proper anode rod wrench — no leaks, no surprises. I recommend wrapping the threads with fresh Teflon tape on every install; it takes thirty seconds and saves you a soaking wet cabinet later.

If you want a budget-friendly backup element to keep in your repair kit without sacrificing quality, the Lrichy 110V/1400W Screw-In Heating Element is worth having on hand. It runs on standard 110V/120V shore power and delivers consistent heat output that matches what Suburban originally specced. The screw-in design makes field replacement straightforward even for first-timers. Just double-check that your water heater tank is completely full before flipping the breaker back on — running this element dry even briefly will burn it out fast.

Step 1: Testing and Removing Failed Components

Start by isolating whether the heating element itself is the culprit. Kill the power entirely and drain the water heater completely. Locate one of the power terminals on the heating element and disconnect it. Switch your digital multimeter to resistance mode (ohms setting). Touch one probe to each terminal of the heating element and note the reading. A healthy heating element measures somewhere between 8 and 15 ohms—usually landing around 10 to 12 ohms for a standard RV unit. If your meter shows “OL” (which means it’s reading infinite resistance) or just won’t settle on a number, that element is dead and has to come out. Readings that drift far outside that 8-15 window tell the same story.

Once you’ve confirmed the element is bad, get it out. Find the right wrench size—usually 1-1/8″ or 1-1/16″ depending on which model Suburban you’re dealing with—and rotate it counterclockwise with steady, gentle pressure. The element will turn slowly at first, then loosen. Don’t be shocked if a little water dribbles out; that happens even when you’ve drained things thoroughly. The whole assembly—element plus rubber gasket—will slide out together. Pull the gasket off and look it over. Cracks, permanent squishing, or visible deterioration means it won’t seal right on the new element. Keep the old gasket nearby as a size reference while you’re working. Look at the element itself for mineral crust, rust staining, or actual breaks in the coil wire—those visual signs confirm what your meter already told you.

Now check whether the thermostat switch is the failing piece. The water heater assembly has two thermostat switches sitting near the top—one is wider and flat (that’s the 12V propane controller) and one has a thinner wire (that’s the 120V electric controller). Since you’re chasing an electric heating issue, focus on the electric one. Pop off the rubber cap that covers the reset button on that switch. Look hard at the wiring connections—scorched insulation, blackened terminals, or burned-looking wire sheathing all point to a thermostat that’s been overheating and needs to be replaced. Disconnect the two power wires attached to the bottom terminals of the thermostat. Flip your multimeter to continuity mode or low ohms. Place the probes on the thermostat terminals. At room temperature, a working thermostat reads close to zero ohms—it conducts electricity freely. If you get no reading or the wires show heat damage, the thermostat is finished.

Step 2: Installing New Components and Testing

Fit the replacement heating element in with the right seal so you don’t end up with a leak. Wipe out the threaded socket in the water heater tank where the old element sat—scrape away any leftover gasket material, mineral buildup, or corrosion with a rag. Add a little mild cleaner if the gunk is stubborn, then dry it. Take your new heating element and slide its gasket—fresh from the box or purchased separately—onto the threads, seating it flat against the element’s flange. Thread the new element into the tank opening by hand first, spinning it clockwise until you’ve gone as far as your fingers will take you. Once it’s hand-tight, use the wrench for one more quarter to half turn. Resist the urge to muscle it—overtightening cracks the porcelain inside the tank or destroys the gasket seal.

Wire up the new heating element according to spec. The element has two terminal posts. Grab your RV’s hot wire (usually black or red) and connect it to one post; run the ground wire (typically white or green) to the other. Most elements don’t care which wire goes where, but match the original installation pattern to be safe. Crimp or nut those connections together using fittings designed to handle moisture and outdoor exposure. Make sure every connection is tight enough that you can’t wiggle it. Tape over each connection with electrical tape to keep moisture out. Verify that no bare copper shows anywhere and that nothing can accidentally touch the heater housing and create a short.

If you’re also replacing the thermostat, do that work with the same care. Disconnect all wires from the old thermostat and unscrew the two bolts holding it to its bracket. Slide the new thermostat into the exact same spot, oriented the same way. Lock it down with the mounting screws, pressing it flat so it can sense temperature properly. Reconnect the wires to the new thermostat’s terminals in the exact order they left the old one—snap a photo of the old wiring before you touch anything if you’re not certain. One wire is the main power feed (the hot supply); the other runs to the heating element. Tighten all connections firmly and wrap them with electrical tape. Slide the rubber reset-button cap back on.

Fill the tank and pressure-test before you declare victory. Close the drain plug at the bottom of the heater and tighten it with your wrench—firm but not cranked down so hard you strip it. Turn on the fresh water supply to the RV and open a hot water tap inside. Let the water pour until it flows steady and clear with no air bubbles, which means the tank is full and all the air is purged. Shut off the faucet and eyeball the new element and all your wire connections for any drops or spray. Switch on the circuit breaker powering the water heater. Set your multimeter to AC voltage mode and test the terminals of the new element—you’re looking for roughly 120 volts (anything from 110 to 125V is normal). Flip the water heater switch on using the RV’s interior control panel. Plan to wait 30-45 minutes if it’s a 6-gallon unit, or 45-60 minutes for a 10-gallon model, so it can climb to full temperature. Run a hot water tap to confirm the system is working. Watch that first heating cycle closely for any weird noises, funky smells, or leaks cropping up.

Why the Suburban 232306 Thermostat Is the Linchpin on Grand Design Reflections

This thermostat is what stands between your heating element firing reliably and cycling into failure—when the 232306 quits, temperature swings vanish and the element either won’t kick on or runs constantly. Without it working right, you’re chasing phantom problems while a Grand Design parked in cold weather becomes unusable.

What works

• Temperature holding becomes rock-solid the moment it’s in place—no more violent swings from tepid to scalding water once the heating element cycles the way it’s supposed to.
• Drops straight into Suburban SW-series installations without rewiring gymnastics or hunting down adapters; it’s the exact cross-reference that dealer parts counters carry.
• The heating element runs its full cycle without false shutdowns, which means a tank that actually heats to temperature instead of quitting early because the thermostat reads wrong.

What doesn’t

• Availability on Amazon fluctuates wildly—this exact part number disappears from stock or takes 2–3 weeks to ship; occasionally you’ll receive a lookalike that fits differently and has connector pins that don’t quite match.
• Requires a full tank drain and external compartment access; if your Grand Design buried the heater in a tight space, you’re spending 60 minutes just getting your hands on those terminals.

I second-guessed whether I had the right thermostat when the connector felt slightly loose on first install, but once I crimped the terminals tighter and ran a test cycle, the heating held rock-solid at 120°F for the first time in months. Check Amazon for the Suburban 232306 thermostat here.

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