Why Reliance Water Heater Not Heating [Reasons + Solutions]

The main reasons behind your Reliance water heater not heating are:

  • Non-functioning thermostat
  • Burned-out heating element (Dry-fired)
  • Or, 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 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 and 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

The thermostat measures the temperature of the water and signals the heating element so start heating water if the desired temperature is more than the current temperature of the water. When the water reaches the desired temperature, the thermostat signals the heating element to shut off.

However, your thermostat may malfunction and stop signaling the heating element to start heating the water. It can happen due to low voltage, faulty wiring, or water in the compartment.

Besides, your water heater won’t warm up if you set the thermostat to a lower temperature setting.


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. 

test the reliance thermostat

First, turn off the power supply to the heater and let it cool completely. Then, remove the access panel, the insulation, and the plastic cover to locate the thermostat. Keep your multimeter at RX1. Set the dial to the highest setting.

Disconnect the power wires from the thermostat so that you can isolate the thermostat from the rest of the electric circuit. Place one probe of the multimeter on the bottom left terminal screw and another probe on the upper left terminal screw.

You should get a reading somewhere close to 0 ohms if the unit has continuity. If you don’t get a reading at all, the thermostat is faulty. Repeat the test on the right side terminals if everything is okay on the left side. If it’s also good, then you have to check the lower part of the thermostat.

Touch one lead to the common terminal and the other one to the upper heating element terminal. If the current water temperature is below the desired settings, the meter should have a resistance reading that’s close to zero. If not, you have a faulty thermostat.

The final step is to rest with the common terminal and the lower heating element terminal. The meter should have no continuity if the desired temperature is more than the current temperature.

Remember that the opposite scenario should occur if the water temperature is above the designated setting. In that case, the lower heating should show continuity and the upper heating element shouldn’t show any continuity.

If any of these tests show conflicting results, you can conclude that you have a bad thermostat. Make sure you test the lower thermostat too. 

If any of the thermostats fail the test, they’ll have to be replaced. Unscrew the screws holding the thermostat in place and press the tabs to remove them. Then, put the new thermostat in and complete the replacement.

It’s an easy enough job to replace the thermostat on your own. If you get the right replacement part, the process should go smoothly. You can hire a technician if you don’t feel okay replacing the thermostat yourself.

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.

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 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, disconnect the power wires attached to the heating element.

test heating elements

Now, check the resistance between the two screws of the heating element using the multimeter. If the reading is between 5 to 25 ohms, it means you have a good heating element. Anything outside this range indicates that you have a bad heating element.

If everything is okay with the upper heating element, check the lower heating element as well. If any of the heating elements turn out to be faulty, they’ll have to be replaced.

Remember to drain the water heater before you replace the heating element. You can do it yourself if you have experience or you can get professional help.

3. Tripped Circuit Breaker

When you are struggling to heat your water heater but it doesn’t heat at all, it’s possible that 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.


If your circuit breaker was tripped, follow these steps to fix the issue:

  • 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.

If the breaker trips frequently, there may be a problem with the voltage or other underlying issues. In that case, we recommend that you hire an electrician to have a go at solving the issue.

4. Tripped Energy Cut-Off Switch

Your Reliance electric heater has a high-temperature limit switch. The switch trips if the water inside the tank heater crosses becomes so hot that it can scald you.

When the ECO trips, the power supply to your electric heater will be cut off and it won’t be heating the water anymore.


The tripping of the ECO is a simple issue that you can fix on your own very easily. You have to press the reset button on the upper thermostat to reset the heater after the ECO gets tripped.

You should hear a clicking sound when you press the reset button. If you don’t hear any sound, it means the ECO wasn’t tripped and something else is causing the issue.

If your ECO trips once in a while, it’s usually nothing worthy of concern. But if it keeps on tripping within a short period, you need to diagnose what’s causing it and fix it ASAP.

5. Plumbing Issues

If you installed your heater recently and you’re not getting any hot water from your heater right away, you may have reversed the hot and water cold lines. The dip tube can also get melted and cause this no heating issue.

The next thing you need to be on the lookout for is if there are any plumbing leaks. Even a small leak on the hot water side can significantly reduce the amount of hot water you get.


If you’ve reversed the hot and cold water lines, you need to correct them to solve the issue. Replace the dip tube if it was damaged. If there are any plumbing leaks, you need to seal them.

Reliance Water Heater Not Heating [Gas Heaters]

We’ve discussed the most common issues that keep the heater from producing hot water in electric heaters. Now, we’ll shift our focus to the gas-powered heaters.

As the mode of operation of gas heaters is different, here are the main reasons why they don’t produce hot water:

1. No 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, makes sure that the gas valve is fully turned on. If it is not completely perpendicular to the gas lines, sufficient gas won’t flow to the unit. So, turn the main gas valve all the way in if it’s not already positioned that way.

Then, try to relight the pilot. Follow these steps to do it:

  • 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).
  • Press the gas control knob and push it down for about 90 seconds.
  • Meanwhile, press the igniter button once every second or so to create sparks and light the pilot.

If the pilot light comes on, the status light in your gas valve will start flashing. You can then adjust the gas control knob to your desired temperature settings.

If you can’t light the pilot after a few attempts, 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 and try to light the pilot light again. If you still fail to light the pilot, you need to contact an expert.

2. Tripped Thermal Switch

Just like the ECO is a safety mechanism in electric water heaters, there are thermal switches in gas water heaters. The switch gets tripped when the temperature in the combustion chamber becomes too hot.

It shuts off the operation of the water heater at that stage. The switch can also get tripped if it’s defective.


You can easily reset the thermal switch by pressing the button located right in the middle of it. You should hear a clicking sound when the switch is reset.

If the thermal switch won’t reset, the switch can be faulty. Check its resistance using a multimeter. If there’s no continuity, it’s damaged and you need to replace it.

3. Faulty Thermopile

Here’s how the pilot, thermopile, and the main burner work together – after the pilot comes on, the thermopile senses the flame and sends a small electric current to start the main burner. But a faulty thermopile won’t do that.

If the thermopile doesn’t receive the signal that the pilot light is on, the main burner won’t come on. Hence, you’ll get no hot water.


Test whether you have a bad thermopile by testing it with a multimeter. You should only test the thermopile if you see that the pilot lit is lit but the main burner isn’t coming on.

Otherwise, there’s no point in doing the test because the thermopile isn’t supposed to work when there’s no pilot light. The resistance of the thermopile should be between 650-850 millivolts after lighting the pilot if it’s good.

If the reading is out of that range, it means you have a bad thermopile and you have to replace it. You’ll have to remove the burner assembly and isolate the thermopile to replace it. Hopefully, replacing it will make your heater work normally again.


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 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 along with their fixes. Hopefully, you can solve these issues after going through this guide.

So, whenever you face such an issue with your Reliance water heater, leave a comment. Our expert will respond to you ASAP with the right solution.

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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