What Can Cause An Electric Tankless Water Heater To Produce Water That's Too Hot To Use?

Posted on: 18 May 2023

An electric tankless water heater uses several powerful heating elements to rapidly heat up the water entering your home, providing you with an instant source of hot water you can use for showering or washing your hands. If the water coming from your water heater is too hot, then you have a problem that needs to be fixed. If you've tried adjusting the thermostat on the unit to a lower temperature setting and the water is too hot to comfortably use, read on to learn what issues can cause the water coming from a tankless water heater to be too hot.  

The Thermostat Is Broken

Tankless water heaters have a thermostat located where the hot water exits the heater. When the water temperature exceeds the setting on the thermostat's dial, the heating elements inside the tankless water heater will turn off. When the temperature goes back down, the heating elements will turn on again.

If the thermostat isn't measuring the water temperature correctly, the heating elements may never turn off, and extremely hot water will come from your home's plumbing fixtures. In order to fix the problem, you'll need to have a water heater repair service test your thermostat and replace it if it's broken.

The Flow Sensor Isn't Working Correctly

Tankless water heaters also have a flow sensor that measures how much hot water you're using. When you turn on a faucet, for example, you use much less hot water than using a shower, so water flows through the tankless water heater more slowly. When water moves through the tankless heater slowly, it has more time to be warmed by the heating elements, so the water heater won't turn them all on. This prevents the water from becoming too hot when it exits the water heater.

If the flow sensor thinks that water is moving more quickly through your water heater than it truly is, then it will turn on all of the heating elements. The water will have a lot of time to heat up, and it will be very hot when it leaves the heater. Like fixing a faulty thermostat, you'll need to have the flow sensor tested by a water heater repair service to see if it's working correctly. You'll have to have it replaced if it's not correctly measuring the flow rate.

Whether you're showering or washing dishes, it's important to make sure that the hot water you're using isn't too hot. Extremely hot water can burn your skin. If the water coming from your tankless heater is too hot, call a water heater repair company in your area and have your tankless unit inspected. The thermostat and flow sensor will be tested to make sure they're working right.