Rheem Water Heater Not Heating [Reasons + Solutions]

The leading reasons for the Rheem water heater not heating include:

  • Bad thermocouple.
  • Restricted pilot assembly.
  • Interruption in the power supply.
  • Faulty igniter.
  • Burnt out heating elements.

Plus, insufficient gas pressure, broken dip tube, defective pressure switch, and bad thermostat are some major responsive factors if your water heater fails to deliver hot water effectively.

rheem water heater not heating

As for a quick fix, reset the tripped circuit breaker of your electric water heater. On the contrary, if it’s a gas heater, monitor whether it is receiving enough fuel from the gas line.

Rheem Water Heater Not Heating [Reasons + Solutions]

Let’s have a short glimpse at the below table, highlighting all the problems reasons, and quick solutions for no hot water issue in your Rheem gas water heater:

Probable ReasonsPossible Solutions
Obstructed pilot tubeClean the blocked pilot tube using compressed air.
Thermocouple issueClean the clogged thermocouple and ensure it holds its place.  
Defective igniter or electrodeReplace the faulty electrode. 
Defective pressure switchTest the switch electrically with a multi-meter and replace the bad one.
Bad gas control valveReplace the non-operational valve. 

1. Restricted Pilot Tube

In case of a heating issue in the Rheem gas-operated water heater, a restricted pilot tube would be the first culprit. After long use, carbon deposits create blockage in the pilot tube, preventing it from lighting the burner. 

restricted pilot tube of rheem water heater

Consequently, it doesn’t get enough fuel to light at all which for why your water heater fails to heat the water in the tank. In another case, the pilot tube termination may bend away from its position which causes shuts off the gas valve.

How To Fix:

For the first step, inspect the pilot tube whether it is bent away from any potions. If it is kinked, only straightening the tube will solve the pilot issue. While doing so, don’t forget to clean the tube inside perfectly. 

Cleaning Tips: Taka compressed air and blow out the debris from the tube. Or, take a needle and gently slide it down into the tube and remove the obstructions.

But if the tube is bent away outwards from the assembly, you have to replace the bad tube with the new one.

2. Bad Thermocouple

A thermocouple is regarding essential equipment in a gas water heater that mainly works to detect the pilot flame. After sensing the flame it creates an electrical signal and sends it to the gas to continue the gas supply process. 

bad thermocouple

But a bad thermocouple fails to sense the heat from the pilot and prevents it from staying light. As a result of this fact, the heater won’t heat the water. Anyway, there are a few factors that are responsible for the malfunctioning of the thermocouple. For instance:

  • Clogged thermocouple.
  • Thermocouple gets out of its position.
  • Or, the thermocouple is defective itself.

How To Fix:

Follow the below few phases to fix the thermocouple issue effectively:

Phase #1- Clean The Clogged Thermocouple

First off, check and ensure that the thermocouple is cool enough to touch. Now inspect the thermocouple where you will find clogged shoots and carbon deposits, created by the flame.

Take a non-soaped steel wool or a piece of emery cloth sandpaper. Start sanding the thermocouple end until it gets clean. When done, wipe down the element with a lint-free cloth.

Phase #2- Position The Thermocouple Correctly

After cleaning the thermocouple, attach and push the thermocouple back in place. Ensure it is not getting out of its position. Otherwise, it will fail to sense the pilot flame to keep the gas valve open. So, the right positioning of this element is quite essential. 

Phase #3- Test The Continuity Of The Thermocouple

In most cases, a bad thermocouple is a culprit itself for why it stops working. To confirm this fact, you can do a continuity test of this element.  

A healthy thermocouple will give a voltage reading between 20 to 30 millivolts. If the voltage isn’t in this range, be sure it is time to replace the bad thermocouple.

3. Defective Igniter Or Spark Electrode

If your Rheem gas water heater won’t heat the water anyway, be sure the igniter or spark electrode is defective and stop operating. An igniter or spark electrode is an essential component of the Rheem gas heater that helps to light the pilot. 

defective igniter or spark electrode

It ensures the fluent ignition process of the system and due to that, the heater heats the water. But for a faulty igniter, the ignition process gets stalled which prevents the gas valve to open. That’s the point the complete heating process gets interrupted.

How To Fix:

For the first step, you have to test the igniter electrically. Take a multimeter and check the continuity to determine if there is a continuous electrical path in the element.

Go through the manual of your Rheem model and compare the voltage reading with the recommended one. If the result shows negative, you have to replace it without any delay. 

Contact a professional if you’re technically inclined to replace the heater component.

4. Malfunctioning Of The Pressure Switch

Almost all water heaters, there equip a draft inducer motor and pressure switch that have a major role in the ignition system. When the fan motor reaches its maximum speed and there is enough airflow in the system, the pressure switch closes, signaling the control board to continue the ignition process. 

But in case of a bad pressure switch, it may fail to close even with adequate airflow. That’s the point, the ignition process will stall, and the water will not heat. Sometimes a failed draft inducer motor is the culprit.  

How To Fix:

  • First off, you can test the pressure switch electrically. Take a multimeter and test the switch to determine if the part has failed.
  • If you don’t find a continuous electrical path to the switch, consider it defective and you need to replace it. 
  • Besides don’t miss testing the draft inducer motor. Clean the dirt or soot around the fan shaft.
  • Check to see whether the internal bearings of the motor wear out. If it’s beyond repair, replace the bad inducer motor. You can expect to pay up to $250 and $500 to replace the inducer motor.

5. Faulty Gas Valve

After attempting all the above steps, if still, the heater is failing to heat the water, a bad gas valve may be the root reason to blame. When the gas valve gets a signal from the pilot light, it opens, allowing the gas to enter the burner and the ignition process starts. 

replace the faulty gas valve

But a bad gas valve fails to do so. It prevents the gas to enter the burner and the water heater will not heat.

How To Fix:

First, you have to check that the gas valve gas enough process and the ignition sources connected to the gas valve are working properly. If so, consider replacing the non-operative gas valve. 

Replacing process a gas valve is quite straightforward and you can do it by yourself. Or contact a professional plumber to perform this task for you. 

No Hot Water-Rheem Electric Water Heater

Here is a short list of all the major reasons and possible solutions for the hot water issue in your Rheem electric water heater:

Probable ReasonsQuick Solutions
Power supply issue> Reset the tripped breaker of your water heater.
> Reset the high-temperature limit from the front of the upper thermostat.  
Defective heating elements> Check the continuity of both heating elements and change the bad one.
Faulty thermostat> Replace the bad thermostat. 

6. Interruption In Power Supply

If there is no hot water from your Rheem electric water heater, the higher chances are the system is not receiving the power from the electrical source. There are a few factors that may come into consideration here. Like:

  • Tripped circuit breaker.
  • Blown fuse.
  • Loose wiring.
  • Tripped high-limit switch.

How To Fix:

For the first step move to your home’s main circuit pane and locate the breaker switch where your water heater is connected. If the breaker has tripped, simply flip it back into the “ON” position.

Check and replace the blown or broken fuses as well. Ensure all the wiring connection from the water heater is in well working order. 

In many cases, the high-temperature limit switch on the upper thermostat gets tripped for why the heating elements don’t get power to heat water. Only resetting the heater can get back it into operation. 

Note: Read why your Rheem water heater is tripping the breaker and how to fix it.

How To Reset Rheem Electric Water Heater

Here are the simple steps to reset an electric water heater:

reset rheem electric water heater

Step 1: First, turn off the breaker to your water heater circuit.

Step 2: Remove the front access panel of the heater using a flat-head screwdriver. 

Step 3: Pull out the insulation and remove the separate plastic, covering the thermostat assembly.

Step 4: You will find a red button that is the high-temperature cutoff reset button. Simply press it firmly down inside and your heater will reset to the default setting.

Step 5: Replace the plastic cover, insulation, and access panel. Finally, turn on your water heater’s circuit breaker.

7. Defective Heating Elements

Almost all electric water heaters feature two heating elements- one is the upper element and another one is found near the bottom of the tank. They mainly convert the electric energy to heat through a resistance process named Joule heating. Then the water heater heats the water using this heat energy. 

test the defective heating elements

If you are encountering a major lack of hot water, we bet that these heating components get worn out and stop operating due to long use. You need to replace the burnt-out heating elements. 

But before jumping in replacement, you can do a continuity test of the elements with the multi-meter to determine if and how there are defective.

How To Test A Water Heater Element With A Multimeter

Follow the below simple steps to test the heating elements electrically:

Step 1: First off, shut off your water heater from the main circuit breaker. Just flip the breaker in to “OFF” position. 

Step 2: Now remove the screws securing the front access panel of the heater tank. Pull out the insulation and detach the plastic safety cover from the element face.

Step 3: Take a non-contact voltage tester and place it near the electrical wires running to the heater element to determine if the electricity is off.  An audible beep alarm signs that the wires are still live.

Step 4: Take your multimeter and set it to the lowest ohms setting. Touch the red probe to one heating element screw and the black probe to the other screw.

Step 5: A well-working heating element will give a reading between 10 and 30 Ω. If you are not getting the reading in this range, indicates that the component is defective and needs replacement.

8. Bad Thermostat

If your Rheem electric water heater is not heating the water anyway, be sure the thermostat is defective and no longer operating. The thermostat, mounted on the exterior of the water heater mainly controls the temperature of the water inside the tank.

rheem water heater bad thermostat

Due to the malfunctioning of the thermostat, it fails to regulate the temperature anymore, and consequently, the tank water will not heat. There are several factors behind the malfunctioning of the thermoset. 

Either there is a minor electrical wiring glitch from the terminals or at times the broken element is the culprit itself. 

How To Fix:

Most electric water heaters have two thermostats. To determine which one is defective, you can do a continuity test of the thermostats. 

If the result shows negative, you need to replace the failed thermostat.  The electric hot water thermostat replacement is comparatively inexpensive, contact a qualified plumber to discuss the matter. 

3 More Major Reasons For Rheem Water Heater Not Heating

Apart from other reasons, there are a few more major reasons, responsible for heating issues in your Rheem water heater. Let’s have a glimpse at all of them with the right fixes:

i). Broken Dip Tube

The dip tube is an internal pipe in a water heater that extends from the cold water inlet to the bottom of the water tank. It plays a big role in the heating process of the system. 

broken dip tube

When the cold water enters the water heater tank, it goes down to the burner through the dip tube, allowing the cold water to be heated quickly.

But if the water heater does not heat a greater chance is that the dip tube is broken. Dip tubes are made of plastic and tend to break easily with the water temperature and high acidity level. 

How To Fix:

The only way to deal with a broken dip tube is to replace it with the new one. On average, a new dip tube will cost about $10 and you can expect to pay about $150 if you’re repairing or replacing it professionally. 

ii). Insufficient Fuel Supply

If you have a gas-operated water heater, look to verify whether it is running through an insufficient fuel supply.

 insufficient fuel supply

It is a quite common phenomenon that most water heater owners encounter. It would happen for any of the below reasons:

  • Air in the gas line.
  • The gas shut-off valve is not open all the way.
  • Insufficient gas pressure from the supply line.
  • Kinked flex tube.

How To Fix:

Follow the below simple steps to fix the fuel supply issue in your water heater:

Step 1: First off, verify the gas pressure of your heater. A propane water heater will give the pressure reading in between 10-13” water column and if you are using natural gas, it should be in between 5-8” water column.

Step 2: Check to see if there is air in the gas line. Simply purging the air from the line will resolve the issue. 

Step 3: Ensure that the gas shut-off valve is opened all the way. The valve lever should be perpendicular to the gas line.

Step 4: At times, the flex tube gets kinked, interrupting the flow of gas. Straighten the kinged tube and the gas will start flowing.

iii). Unmanageable Hot Water Demand

If your water heater is not producing hot water, your unit may be too small that fail to meet the household’s hot water demand. Generally, a water heater can ensure up to 75 percent of its capacity as hot water. The demand might be exceeding the capacity of the water heater. 

What To Do:

  • First off, turn off the faucets if multiple ones are open at a time.
  • If still the same issue, you have to consider upgrading your water heater tank with the bigger one to meet up all the household needs. 
  • A medium water heater storage tank of 80 gallons will be enough for three to four people. But you have to buy a large tank to cater to the hot water demand of four to six people.


How much does it cost to replace a water heater thermostat?

The replacement part of a thermostat will only cost around $20-$30. But you can expect to pay around $100 to $350 on average if you are hiring a professional to replace a thermostat.

How do I know if my water heater thermostat is broken?

There are a few major signs, determining that your water heater thermostat is no longer operating. Like no hot water, the water isn’t hot enough, slow hot water recovery or the high limit switch keeps tripping.

Does a water heater require regular maintenance?

Yes! You have to be concerned about the regular maintenance of your water heater to increase its efficiency. Like testing the TRP valve, insulating the pipe, checking the anode rod, flushing the tank every 6-12 months, and so on. 

End Remarks!

Well! That’s all from us here. Hope that there should be no queries left over on why your Rheem water heater not heating. 

As you’ve observed above, Several common problems may interfere with the normal heating operation of your water heater. The problem is easily be solved simply by resetting the system. 

But when the term comes to any complex problems, you’ll need a detailed troubleshooting guide. That’s the point, our complete discussion is enough to prove well. Don’t forget your valuable thoughts to us through comments.

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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