Suburban SW6DE and SW10DE Troubleshooting
On this page (7 sections)
The Short Answer: The Suburban SW6DE (6 gallons) and SW10DE (10 gallons) are RV water heaters with a direct-spark propane burner and a 120-volt electric element. Find out which side has stopped: if one fuel still heats, the tank and water supply are fine and the fault is in the other side’s controls. If neither heats, look first at an empty tank, the bypass valves, or a tripped high-limit.
Confirm the model
The model and serial number are on a label inside the outside access door. “SW6DE” and “SW10DE” mean a 6- or 10-gallon tank with direct spark ignition and an electric element. Variants with extra letters (such as SW10DEL) share the same basic layout but can differ in door, plumbing, or controls, so order parts by the full model number. Suburban also makes gas-only models without the “E”; they have no electric element, switch, or electric high-limit.
How much hot water to expect
Six gallons is small. A long shower, especially with a high-flow head, can empty an SW6DE of hot water in a few minutes, and the heater then needs time to recover. The SW10DE holds more but works the same way. Running gas and electric together shortens recovery. If showers are short but the water gets hot again after a while, the heater is probably working as designed. A low-flow shower head and turning the water off while lathering help more than any setting.
Start-of-season checks
Many problems on both models appear on the first trip after storage:
- Bypass valves. After winterizing, the bypass routes water around the heater. Set it back to normal so the tank fills.
- Fill before firing. Open a hot tap until water flows steadily with no air. Turning on the electric element with an empty tank burns it out almost immediately.
- Anode and plug. Suburban tanks use a magnesium anode as the drain plug. Reinstall or replace it before filling, and watch for drips once pressurized.
- Burner area. Look through the outside door for insect nests or webs in and around the burner tube. Nests are a common reason for no-light or a weak flame after storage.
- Battery. The ignition board needs steady 12-volt power; a weak battery causes failed lights and lockouts.
Symptom guide
| Symptom | Where to look | Details |
|---|---|---|
| Gas heats, electric does not | Shore power, coach breaker, electric switch, element, high-limit | Not working on electric |
| Electric heats, gas does not; lockout light | Empty LP, air after a cylinder change, low battery, insect nest in burner tube, igniter or board | Not working on gas |
| Gas lights, then goes out | Flame sensing, electrode position, low LP pressure, wind at the vent | Note when it happens |
| Neither heats | Empty tank or bypass, a tripped safety limit, or no LP and no 120 V | Checks above, then a technician |
| Both heat, but hot water runs out fast | Normal tank capacity, or a mixing problem at the shower valve | See above |
| Drip from relief valve while heating | Normal expansion in a closed system, or a failing valve | Note if it drips only while heating; technician if constant |
| Water around the heater or at the bottom center of the tank | Anode plug threads or seal, relief valve, fittings | Suburban RV water heater leaking |
| Rotten-egg smell in the hot water | Reaction between the anode and the water supply | Water-quality issue, not a gas leak |
| Popping or rumbling when heating | Scale and sediment on the tank bottom or element | Flush the tank as Suburban’s manual describes |
Owner-level actions
- Confirm the LP cylinders are open and the stove lights.
- Check battery voltage on the monitor panel; low voltage causes ignition failures.
- Check that the water heater breaker in the coach’s panel is on; reset it once if tripped.
- Make sure the bypass is in the normal position and the tank is full before switching on either fuel.
- Turn the gas switch off and on once to clear an ignition lockout. If it locks out again, stop.
- Flush the tank and inspect the anode as Suburban’s manual describes, with the heater off and cool.
- Note whether you hear clicking, see a lockout light, or smell anything unusual.
What the technician will check
An RV technician tests the failing side before replacing parts. On the gas side: LP pressure, the electrode and its gap, the gas valve, the ignition board, and the thermal cutoff and high-limit that stop the burner on overheating; they will also clean the burner tube. On the electric side: voltage at the heater, the element, the thermostat, and the manual-reset high-limit. Resetting a tripped high-limit is done with power disconnected and only after the cause is known; see how to reset a Suburban water heater.
These are part repairs that leave the tank in place. Replacing the whole heater makes sense when the tank leaks, was split by freezing, or has corroded through after years without anode maintenance.
Frequently Asked Questions
Q: How long does an SW6DE or SW10DE take to reheat? A: It depends on the incoming water temperature, the tank size, and whether you run gas, electric, or both. Gas recovers faster than the 1,440-watt element; both together is fastest. If recovery has become much slower than it used to be, scale or a weak element may be the cause.
Q: Why does it work on gas only at certain campsites? A: Strong wind at the exhaust vent can blow out or disturb the flame, and low battery voltage after a night off-grid can prevent ignition. If the pattern is clear, mention it to the technician.
Q: Can an Atwood or Dometic part fit a Suburban SW6DE or SW10DE? A: Generally no. Atwood and Dometic heaters use different tanks, boards, and controls. Use Suburban parts that match your full model number.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Suburban: service and support (opens in a new tab)Identify the appliance behind the RV badge and obtain its operating instructions.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
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