Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses troubleshooting a water heater.
I am not getting AC voltage to my Suburban SW12DE water heater. I have Ohmed out the wiring from the input to the switch through the element. It seems to be OK. Element has 10.6 ohm resistance. I am stumped. —Kenneth
Your Suburban SW12DE is a 12-gallon water heater that runs on propane or 120-volt electrical power. The first thing I always check in this type of situation is, does it work on propane? For any appliance that has dual power sources, one should always check both operations. This will eliminate the module board.
Next, check the emergency cut-off and/or high-limit switch. Your unit has a switch that shuts off if the temperature gets over 180 degrees.
The standard temperature of your water heater is 130 degrees. If it goes over 180 degrees the reset button will trip and needs to be reset.
Make sure there’s water in the water heater before starting it up after storage
The most common issue with units that feature a heating element is starting the water heater up after storage without water in the tank. This will overhead the unit and burn out the heat element.
Verify you have 120-volt power to the rig by either shoreline power or the generator running.
Check the circuit breaker in the distribution center.
Turn on the power switch inside the rig and the one located at the front of the water heater in the lower left. This supplies 120-volt power to the high-limit switch and thermostat.
With your multimeter, check for 120-volt power at the thermostat and heating element. My guess is your thermostat is either tripped or bad, since you have checked the resistance at the heat element.
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