How To Test Water Heater Thermostat With Power Off

Screw the panel back in.

How to test water heater thermostat with power off. You should read 240 volts. This insures that the thermostat will call for heat. You may insert the power pluck and hold a tester at the heater s connecting point to check if the power is available. An electric water heater has a thermostat like a tankless water heater.

If you have a reading then the power is turned on switch it off and check again. Fit the insulation covering back on and place back behind the panel. This will force the lower thermostat to call for heat and the upper thermostat to shut off. Head to your circuit board and turn off the water heater s breaker.

Before you start working on the hot water heater confirm that the electric power in the room the heater is in is off. Hold the a and b points of the series lamp with the heater s pluck. Touch one meter lead to the top screw and the other lead to the metal body of the water heater. If you get the reading of 240v on terminal 1 and terminal 3 then the power is on but if you get no readings then the power is off.

There must be no power on the unit. Place the lead of your multi meter on the incoming power side of the thermostat terminal of the lower element and the other lead on the opposite water heater element terminal. Locate the breaker inside the panel box labeled water heater or hot water and turn the breaker off. See if electrical current is going to the water heater by touching the tip of the voltage detector to the wires leading into the thermostat.

Remove the outside access covers use a 1 4 inch nut driver or flathead screwdriver to remove the upper and lower thermostat access panels. If the thermostat has not defected then the bulb will light. The meter should read somewhere between 220 and 240 volts. If the power supply is okay then manage a series lamp or multimeter.

Make sure that the power is off. If not then you need to replace the lower thermostat. Luckily testing and fixing a faulty thermostat requires a few tools such as a multimeter and a pair of screwdrivers. The access panels are on the side of the electric hot water.

Turn the water heater circuit breaker off inside the main service panel. You want to use the water heater tester to check terminals 1 and 2 on the upper element this will be the lower set of 1 and 2 terminals. Push the red reset button to set it with the water heater. The reading should be between 110 and 120 volts.

Remove the upper and the lower access panels with a phillips screwdriver. Test the power with a non contact voltage detector to make sure it s off. If the connection point does not get electricity then change the power cable and start your heater. To look at the faults in the upper thermostat you need to turn off the lower one.

Turn the power back on and place your ear to the drum of the heater. Turn the temperature to its highest setting on the upper element. Check the power supply of the thermostat. How to test an electric hot water heater thermostat.