Why Reliance Water Heater Not Heating [Reasons + Solutions]

The leading reasons for your Reliance water heater not heating due to:

  • Non-functioning thermostat
  • Or, burned-out heating element (Dry-fired)
  • Improper temperature setting

You can instantly fix the problem by adjusting your right temperature. If your problem isn’t solved yet, we bet there may be trouble either with the circuit breaker, or the upper heating element.

reliance water heater not heating

However, we have explored each of the culprits behind the issue. So, continue reading the guide to know the details, definitely, you will get your desired solution. Let’s go ahead.

Table of Contents

Reliance Water Heater Not Heating [Reasons + Solutions]

Here, we will find out the most common reasons that prevent your Reliance water heater from heating and provide you with effective tips to fix the problems. So, let’s dive in!

diagram of reliance water heater

Before going to examine in detail, notice the diagram of your water heater. The below image is representing the overall status of how your Reliance water heater supplies hot water. Now, start exploring right here what is wrong with your heater to get hot water. 

Note: You Can also read how to fix the reliance 606 water heater pilot won’t stay lit.

1. Defective Thermostat

A defective thermostat is the number one villain that prevents your water heater from heating properly.

test the reliance thermostat

Basically, a thermostat is a temperature-activated controller that works as a safety device. Plus, it helps to measure the electricity of the upper and lower elements to run the heater. Then it also energizes the elements to “call for heat.”

However, your thermostat may malfunction due to low voltage, faulty wiring, or water in the compartment.

If these happen, the thermostats can’t signal to the gas control valve. As a result, the pilot doesn’t light and stops heating the heater automatically. 

Besides, your water heater won’t warm up if you set the thermos to a lower temperature setting. Whatever, here is the solution to the problem.


To fix the issue, first, check the thermostat to see whether it is operating normally. Let’s follow the below steps to test both thermostats. 

Step 1: How To Test The Upper Thermostat

First, turn off the power in all ways. Let it cool completely. Then, remove the access panel to locate the thermostat. Keep your multimeter at RX1. Set the dial to the highest setting.

Place the one-meter probe on the bottom left terminal screw and another probe on another terminal screw. You should get a reading somewhere between 10 and 13 ohms. If you don’t get a reading at all, the thermostat is faulty.

Second, test the right side of the thermostat in the same manner as you did on the left side. Here, after placing the multimeter’s probe on the terminal, you will hear the sound of a click-off. If you don’t get a sound or reading at all, the thermostat is defective.

Remember, if the upper system is receiving power but your heater isn’t heating, replace the upper thermostat and check out the lower part to ensure

Step 2: Test The Lower Thermostat

It is easy to test because the lower thermostat has only two terminals. Take a screwdriver and turn the thermostat all the way up. Touch a meter probe on each of the terminal screws and another on the other terminal. Now, you should get a minimum reading with the meter.

test lower thermostat

If there is continuity, the thermostat is good, but there is no continuity, indicating that the thermostat has become faulty. After completing the steps, make sure to adjust the thermostat temperature back to normal.

After setting your desired temperature, if you need to change a thermostat, the replacement instructions are quite simple, just as you did removing the faulty thermos.

Last, place the cover panel and insulation, and then screw them into place. Attach all the wires to the thermos where you detached them first. Tight enough so that the electric power will complete a circuit through the system. Hopefully, your heater will be heated as usual.

If your heater isn’t heated after replacing the thermostat, check the heating elements. Here is a helpful guide on how to replace the thermostat.

2. Faulty Heating Elements

The next cause of your Reliance water heater not getting hot enough is a faulty heating element. In most cases, there are two heating elements in an electric water heater that heat the water. 

Mechanically, the heating element is a heater component that makes up a metal wire heated by a controlled electric current. Normally, the elements take a little time to heat properly.

When you turn on your heater, water goes through the lower heating element to the upper elements, which heat the water.

But if either of the elements is faulty due to a power outage or overheating, your heater won’t be heated at all. Plus, these may happen when it gets burned out or bent. In most cases, it isn’t repairable, but there is a 90% chance that simply changing one or both of the heating elements will solve the issue.


First, check whether the element is good or bad. Normally, it lasts for 10–12 years. For this purpose, you will need:

  • Screwdrivers
  • Wrenches and a
  • Multimeter

How Do You Test Heating Elements

First, turn off the heater’s power at the electric circuit panel. Remove the cover panel to get access to the heating elements. Then start for continuity—the ability to pass electricity from one end to the other. Place the multimeter probe into each of the heating elements.

test heating elements

If you get reasonable resistance (Kilo or 1000 Ohms), this indicates the heating element is fine for work. But the infinitive resistance hints at broken elements. Then the only option is to replace your damaged or faulty element.

For this purpose, ensure that its part number, size, resistance (in ohms), and current capacity (in amps or amperes) are the same when you are replacing the heating element.

Because it usually requires setting at a voltage (120V or 240V) for better performance. Finally, reassemble the units, turn them on, and test for continuity. We hope your problem will be solved.

Note: If your Reliance water heater is not heating after replacing the thermostat or heating elements, we can bet that there is an issue with your circuit breaker.

3. Tripped Circuit Breaker

When you are struggling to heat your water heater but it doesn’t heat at all, surely the circuit breaker that controls the water heater has tripped or the fuses have blown out.

tripped circuit breaker

Normally, a circuit breaker may trip when the power supply to the water heater is interrupted.

Plus, this may occur when an abrupt high voltage goes through the circuit. To prevent electrocution, the switches may trip to protect against this excessive electric flow.

On the other hand, your breaker may be short-circuited or tripped due to-

  • A bad breaker or wiring.
  • A loose connection in the electric panel.
  • Burned-out heating element.
  • Worn-out breaker.
  • A faulty thermostat.

As a result, because of the above responsive factors, your water heater will not heat to the point.


First, locate the red reset button near the thermostat, and then hold on to press and release it. Now, your water heater breaker’s electric power will be restored to turn on your heater, which will be heated as you desired.

Even if the breaker trips again, try resetting your breaker. Here’s how to do it:

How To Reset A Circuit Breaker

  • First of all, switch it to the off position and find the breaker box that controls your water heater’s electronic functions.
  • Simply wait 5 minutes for the breaker to be reset and returned to the ON position.
  • In order to return to their original position, flip up the tripped breaker.
  • This step should reset your water heater and allow it to work again.

Even if the breaker trips frequently, there may be a problem with the voltage.

4. Malfunctioning Voltage At Outlet

If there is no problem with the breaker and your water heater is still not reaching the desired temperature, the next step is to check the voltage at the outlet. This step will confirm if there is a problem with your water heater or wiring.


Turn the heater off and locate the wires connected to the elements and thermostat. Make sure it’s tight and secure. If you find any loose connections to the main electric board, re-tighten them with a screwdriver or wrench. Oversure that your wiring is fine or up to code. 

If the problem isn’t solved yet, you can also check the wiring on the line for broken or loose wiring. When there is no issue with the lines but the breaker is tripping frequently. Last but not least, check for loose or broken wires on the water heater.

How To Test Voltage At The Outlet

In order to fix the voltage issue, check the outlet power by following the instructions.

First, locate the electrical outlet. Then, unplug it from the outlet.  Take a multimeter to inspect the voltage of the heart’s plug. If you find the right voltage, the problem is with your water heater.

But if you identify that the wire has been broken, replace it altogether for better performance. Now, try plugging it in to see if it’s working; Expectantly, you will get the right voltage for your water heater.

5. Tripped High-limit Switch

Your Reliance electric heater has a high-temperature limit switch. The switch trips if the heater crosses temp 180 degrees. As a result, your water heater won’t produce hot water and even can stop working. However, this shouldn’t be a continuous problem. So, fix it ASAP.


Locate the switch on the side of the tank, on a panel. You should try pressing the reset button to get your heater running again.

Even when the power doesn’t restore the power system, you need to change your Energy Cut-Off Switch. If you are not good at replacing the part, consult a professional to address and replace them.

6. Restricted Pilot Light

If your gas water heater isn’t heating, the pilot light has most likely gone out. Mainly, the pilot blows out due to a defective gas valve or an interrupted gas supply.

Typically, there should be a small flame that looks like an LED light that can be seen through the viewing window at the bottom of the heater. So, it is necessary that the pilot light stay lit when your heater is operating normally. Otherwise, the system can’t burn to heat the water.

Furthermore, the pilot tube may become clogged due to deposited carbon or other causes, preventing the pilot from lighting. Check to see if it’s clean.


First, check the gas level in the water heater. If it is too low, refill it again. Then, check and clear out debris from the pilot light tube by using a needle so that it can supply gas flow uninterruptedly. If you find any flex tubes, clean them to remove any obstruction.

After removing the debris, if you can’t see the flame of the pilot light, try relighting the pilot light. As the pilot light is compulsory for the heater’s performance. Let’s know:

How To Relight The Pilot

  • Turn off the gas valve.     
  • Wait 5–10 minutes to clear out all the gas from the heater.
  • Locate the gas valve and turn the control knob to the pilot position (low setting).
  • To start the flow of gas for the pilot, depress the knob or individual pilot button.
  • Keep pressing the button down.
  • After pressing and holding it down for 1 minute, then release it.
  • Make sure the pilot stays lit as usual.

After successfully completing the steps, you will see a blue flame on the burner through the viewport. Listen, you’ll hear a sound as the burner ignites. Now, set your desired temperature setting.

Note: if the above-discussed issue isn’t with your heater, check the temperature setting.

7. Improper Temperature Setting

Improper thermostat temperature setting is a common reason for not preheating the water heater. This may happen when the thermostat temperature setting is changed accidentally.

improper temperature setting

Plus, we have identified other common issues that cause a water heater’s temperature to fluctuate due to:

  • Damaged burner assembly or the gas control valve
  • A temperature release valve is included.
  • Leakage in the water tank

Therefore, all the above issues might affect the thermostat’s performance. Finally, your water heater will no longer pre-heat.


Increasing the temperature is the simplest and most effective way to repair a broken thermostat. So, increase the thermostat temperature to 115–120 degrees F. during winter. Adjust your desired temperature setting.

If the water does not heat up when you turn up the temperature, you might have a faulty thermostat. The solution is to replace the thermostat, as mentioned in the first para.

8. Damaged Burner Assembly

Your Reliance gas water heater won’t produce heat if the burner assembly can’t function properly. A damaged gas burner or gas control is another possible cause of your water heater not getting hot enough.

damaged burner assembly

Basically, the burner assembly is an essential component that ignites the fuel in your system and maintains the flame, and helps create the heat that is distributed into the water heater.

Plus, the burner parts include an igniter or electrode depending on your heater. When you turn on your heater, the igniter should spark to ignite the burner and the heater. But your water heater will fail to warm up if the burner assembly is dirty or non-functional.


First, turn off the water heater and unplug it from the power outlet. Then, open the access panel and front panel to get access to the burner assembly. Remove the burner assembly carefully. Now, you need to clean.

To Clean It:

Use a brush or wet cloth to clean out debris from the burner assembly. Reattach the parts as you removed them, and then turn on your heater to check if they are working properly.

If the problem hasn’t been resolved by now, you may need to replace the burner assembly.


How long does a water heater take to heat after replacing the elements?

Your electric water heater will take 60–80 minutes and 30–40 minutes for a gas heater after replacing the elements like a tripped breaker, wiring, and a defective thermostat. 

What are the symptoms when my fuse has blown out?

A blown fuse results in the total loss of the water heater. Plus, if the switch blows away, your heater will be too hot and the high-limit safety switch will cut off the power.

Where is the reset button of the Reliance water heater and how to reset it?

The electric tank water heater has a reset button on the upper of the electronic thermostat. But there is no reset button for a Reliance gas water heater. To reset, press the red reset button. You’ll get a click sound after resetting successfully.


Now, we strongly believe that you have already identified the culprits that are mainly responsible for your Reliance water heater not heating. Basically, your water heater won’t heat when the heating element or circuit panel is malfunctioning.

Whatever the reasons, we have already outlined easy and effective tips to resolve your water heater heating problems by yourself.

So, whenever you will face such an issue with your Reliance water heater, feel free to knock us with your comments. Our expert will respond to you ASAP with a well-proven solution.

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