Rheem Electric Water Heater Troubleshooting

Rheem Electric Water Heater Troubleshooting

This guide on Rheem Electric Water Heater Troubleshooting will walk you through common problems of the water heater, including: 

  • The unit makes rumbling noise
  • Relief valve producing popping noise 
  • Rattling noise during periods of water usage
  • Not enough or no hot water
  • Water is too hot 
  • Can’t set above 140° F

To resolve those issues, continue to read.

Rheem Electric Water Heater Troubleshooting [5+ Problems & Solutions]

From this chapter, you will discover the solutions to some common problems of your Rheem Electric Water Heater. 

1. Water Heater Makes Rumbling Noise

You will hear a gurgling noise from the water heater while operating it if scale or buildup forms on the heating element. In this case, cleaning the scale formation from the heating element will stop the unit from making noise. 

In the ‘How To Section’ below, I will walk you through a step-by-step guide to clean the heating element. 

How To Fix: 

You must take off the cavity insert crossbar to clean or replace the heating element. And instructions here will help you to do so: 

  1. Turn the power off to the water heater by flipping the circuit breaker down.
  2. Remove the jacket access panel using a screwdriver and fold away the insulation. 
  3. Now, rotate the crossbar up and down until it comes off from the remainder of the cavity insert. Once it comes off completely, discard it aside. 
  4. Use a socket wrench to remove the thermostat or heating element and inspect the condition of it. To clean this component, use a cleaning solution of vinegar & water and a scouring pad. If the heating element starts corroding, you must replace it with a new one. 
  5. Once you clean or replace the heating element, put the insulation and the jacket access panel back into their places. 
  6. Finally, restore the power to the unit and turn the unit on.

2. Relief Valve Producing Popping Noise Or Draining

The pressure relief valve will make a popping noise if the pressure builds up caused by thermal expansion in a closed system. 

As the unit heats water, water expands in volume and creates an increase in the pressure within the water system, which is referred to as thermal expansion. 

A ‘closed water system’ prevents the expanding water from flowing back into the main supply line. 

And the result of thermal expansion can create a rapid and dangerous pressure increase in the unit and system piping. This rapid increase of pressure can quickly reach the safety setting of the relief valve, causing it to operate each heating cycle. 

How To Fix: 

To control the thermal expansion, install an expansion tank in the cold water line between the water heater and the check valve. An expansion tank is specially designed with an air pressure cushion built in that compresses . 

As the system pressure increases, the tank will relieve the overpressure condition and eliminate the repeat operation of the relief valve. 

However, I highly recommend you to contact the water supplier or your plumber to take further assistance regarding this matter. 

3. Rattling Noise During Periods Of Water Usage

It’s normal. 

In other words, you don’t need to take any corrective actions. It actually happens when the internal heat trap fittings are in operation.  

The good news is- your water heater will not indicate a need for service. In short, the rattling noise you hear during periods of water usage is not a problem at all. 

4. Not Enough or No Hot Water

Your water heater won’t provide a single drop of hot water due to the following reasons: 

  • Water usage might exceed the capacity of the water heater
  • A fuse gets blown out or the circuit breaker gets tripped
  • Electric supply to the unit may go off
  • The thermostat may be set too low 
  • Hot water faucets are leaking or open
  • Improper wiring
  • Manual reset limit 
  • Cold water inlet temperature may be colder during the winter months 

How To Fix: 

I already wrote an article on Rheem Electric Water Heater Not Heating. In that article, I described everything you need to know to solve the issue. 

5. Water Is Too Hot

If you set the temperature too high, the water heater will heat the water at a higher setting. 

How To Fix: 

Adjusting the temperature dial to a lower setting will help you fix this issue. To adjust the temperature, what steps you should follow: 

  • Turn the power off to the unit.
  • Expose the thermostats by removing the access panel and the insulation. 
  • Using a screwdriver, set the thermostats dial pointers to the desired temperature.
  • Put everything like the insulation and the access panel back into their places and turn on the power to the unit. 

Note: Never set the temperature above 125°F as it could cause severe burns or even death from scalding. FYI, you can check out the following table that displays the time/temperature relationships in scalds. 

TemperatureTimes To Produce A Severe Burn
120°FMore than 5 minutes
125°F1 ½ to 2 minutes
130°FAbout 30 seconds
135°FAbout 10 seconds
140°FLess than 5 seconds
145°FLess than 3 seconds
150°FAbout 1 ½  seconds
155°FAbout 1 second
Source: Rheem Electric Water Heater Manual

6. Cannot set above 140°F

This problem only occurs with Rheem Electric Water Heater with an electric controller. If you set the Electronic control high temp configuration to No, you can’t set the temperature above 140°F. 

How To Fix: 

To resolve this problem, go to the Configuration menu section on programming the electronic control. 

However, it’s a safety feature as well. I don’t recommend you to set the temperature above 140°F as it could cause severe burns or even death from scalding. 

How Do You Reset A Rheem Electric Water Heater?

Resetting the Rheem Electric Water Heater is simple. It features a temperature control limit system called ECO or reset button. It is located on the upper heating element. By pressing that button, you can reset the unit correctly. 

To reset the Rheem Electric Water Heater, follow the below instructions:

  • Turn off the power to your water heater. 
  • Unscrew the upper access panel and take off the insulation, which will expose the red reset button. 
  • Press the red button, which will reset the unit successfully. 
  • Lastly, replace the insulation and the access panel to the unit. Then, turn on the power to the unit. 


Why is my electric water heater not getting hot?

Your electric water heater, either it comes from Rheem or other brands, won’t get hot enough if: 

  • Circuit breaker for the unit gets tripped
  • A blown out fuse
  • Manual reset limit
  • Heating element gets corroded 
  • No electric connection to the unit

Why is my electric water heater only warm?

Electric water heater only warms but doesn’t heat the water as it intended if the power has been cut to the water heater. Most often, a tripped circuit breaker is the culprit that causes the unit to notwarm. 

Why is my water cold with an electric water heater?

The electric water heater will produce cold water if you set the temperature too low or the heating elements burn out. 

Why is my electric water heater only hot for a few minutes?

If your electric water heater only heats water for a few minutes and you’re going through this issue consistently, I bet the upper heating element is at fault. To fix this problem, replace the upper heating element. 


Rheem Water Heater is reliable and delivers hot water in the cold days of winter. But it’s not beyond malfunction. And this guide will help you troubleshoot your water heater when it fails or acts up. So, bookmark this article and get it handy when you need it. 

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