Table of Contents
The thermostat is a thermistor that responds to heat by producing a small electric current. The current increases when water temperature increases, and drops when temperature drops. Changes in the electric current cause gas control to turn ON and OFF. When gas control turns ON, it releases gas to burner.
How do electric hot water heater thermostats work?
A thermostat is essentially a temperature-activated switch. When the thermostat senses a water temperature below its set point, it will energize one of the elements in response to this “call for heat.” The back of the thermostat senses the temperature of the outer layer of the tank.
How do I know if my hot water heater thermostat is bad?
If you turn the hot water tap and cold water runs out, then the upper thermostat is damaged. But if the water is hot that becomes later becomes cold, then you have a damaged lower thermostat.
What happens if water heater thermostat goes bad?
Each thermostat controls a heating element, which heats the water. When the water reaches the desired temperature, it’s the job of the thermostat to shut the heating element off. But if one or both thermostats go bad, it can force the heating element to run continuously, overheating the water.
Which element heats up first on electric water heater?
Initial start up: When the tank is full of cold water, the upper thermostat will take priority and heat up the top portion of the water to the setting of the thermostat. Once that temperature has been reached, the thermostat will then flip power down to the lower thermostat.
How do I adjust the thermostat on my electric water heater?
Start by turning off power to the water heater at the circuit breaker. Find the access panel for the thermostat(s) and use a screwdriver to remove the panel. Peel back the insulation. Use a flathead screwdriver to adjust the thermostat up or down.
How do I know if my thermostat is working properly?
When a thermostat is working properly, it should display an accurate temperature of what it feels like inside your home. But if the room feels much hotter or colder than the display temperature, that means your thermostat can’t accurately measure the room’s temperature.
How long should a hot water thermostat last?
Traditional hot water cylinders: 8-12 years. Heat Pump water heaters: 10+ years.
How do I know if my thermostat is low?
Test the lower portion of the thermostat, by touching one lead to the common terminal (next to the temperature setting) and the second lead to the left heating element terminal. If the water in the tank is below the thermostat’s set temperature, the multimeter should read close to zero ohms of resistance.
What causes a water heater thermostat to burn up?
Chances are you have a failed or failing element that is drawing too much power, but not quite enough to trip the breaker or you have a failed thermostat. It looks like the main damage is the insulation of the wire that I assume goes to the supply. You will need to replace or, if possible, repair the wire’s insulation.
How much does it cost to replace a water heater thermostat?
Thermostat. You may also run into problems with the thermostat on your unit. The cost to repair or replace one is usually $150 to $200.
How do I reset my water heater thermostat?
Somewhere on your electric water heater, you’ll find a reset button. It’s usually red and often located near the thermostat. It may also be hidden behind a removable metal panel on the unit—and then behind some insulation. Once you find the button, push and release it.
Do you have to drain a hot water heater to change the thermostat?
Always disconnect the power or shut off the breaker before doing any work on a water heater. To change thermostats, you will need to remove the access panel and safety cover (do this for both upper and lower access panels on dual element units).
Should both thermostats on an electric water heater be set the same?
The majority of electric water heaters have two thermostats: an upper and a lower, located under two control panels. To ensure your electric water heater works as efficiently as possible, you should set both of the thermostats at the same temperature.
Does the top or bottom element heat first?
The top element is always the first one on. In fact the bottom element does not receive power until the top thermostat is satisfied.
What temperature should my hot water heater be set at?
120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting. Most experts agree that anything below 120 degrees creates a risk for bacteria to develop inside your water heater from stagnant water, such as legionella that causes Legionnaire’s disease.
What causes a thermostat to fail?
Thermostats fail because they become weak, stuck open or stuck closed. When a thermostat is stuck open, coolant constantly circulates and the engine takes longer to reach operating temperature.
How can I tell if I need a new thermostat?
7 Signs You Need to Replace Your Thermostat Your HVAC Keeps Turning On or Off. Faulty Thermostat Readings. Suspiciously High Energy Bills. Constant Temperature Shifts. Thermostat Is Too Old. Thermostat Fails to Respond to Changed Settings. Your HVAC System Short Cycles.
How do you know if you need a new thermostat?
Signs You Need a New Thermostat Heating or cooling system will not turn off or on. The temperature reading is incorrect. Recent spike in your energy bill. Frequent temperature fluctuations. Thermostat is 10 years old or older.
