Reliance 606 Water Heater Thermocouple Replacement

This is a complete guide on Reliance 606 Water Heater Thermocouple Replacement. And I will take you through the following: 

• How do you know if your water heater thermocouple is bad?
• 5 simple steps to replace the thermocouple on Reliance 606 Water Heater
• And a lot…

So, keep reading till the end and make the replacement which will save you both money and time. 

Table of Contents

• How Do You Know If Your Water Heater Thermocouple Is Bad?
• Reliance 606 Water Heater Thermocouple Replacement [5 Simple Steps]
  • 1. Turn The Gas Supply Off 
  • 2. Disconnect Every Connection From The Gas Control Valve 
  • 3. Remove The Burner Assembly Out of The Combustion Chamber 
  • 4. Remove the Old Thermocouple & Replace It With A New One 
  • 5. Reassemble Everything To Complete The Replacement Workflow
• FAQs 
• End-Note

How Do You Know If Your Water Heater Thermocouple Is Bad?

The pilot light won’t stay lit is the main indication that tells your water heater thermocouple is at fault. Of  course, there are other culprits that are also responsible for the pilot light not staying lit. 

Fortunately, I wrote a guide on Reliance 606 Water Heater Pilot Light Won’t Stay Lit. You can check the article here to discover what causes the pilot to not stay lit. 

However, the best way to determine whether the thermocouple is bad or not is to test the thermocouple electrically. 

And the the below procedure will help you test the thermocouple: 

First off, set up your multimeter for direct current and ensure the range is less than 1 volt. 

Secondly, remove the thermocouple wire connector from the gas control. In some cases, you may need to rock the wiring harness back & forth to pull out. 

Then, attach the red positive lead to the red thermocouple wire and attach the black lead to the white thermocouple wire. 

Now, set your gas control to the Pilot and light up the pilot following the instructions mentioned in the manual. 

Keep pressing the igniter while holding down the pilot knob. You will know the pilot is lit as the voltage will start climbing. 

Continue to hold down the gas control knob until you reach the maximum voltage. It may require at least 3 minutes to reach the maximum voltage. 

A functional thermocouple will read anywhere from 650 to 850 millivolts or somewhere in between in an open circuit test. If the reading goes out of range, I bet the thermocouple is bad.

In this case, you must replace the thermocouple with a new one. And the next chapter will take you through the step-by-step guide to replace the thermocouple like a pro. 

Reliance 606 Water Heater Thermocouple Replacement [5 Simple Steps]

This chapter will walk you through 5 simple steps to replace the thermocouple. 

1. Turn The Gas Supply Off

To begin with, set the gas control/temperature knob to the Off position. I highly recommend you shut off the main gas supply valve before performing any maintenance or replacement workflow. 

You can find the main gas supply valve beside the water heater. When you shut off the valve, the position of the valve will be perpendicular. 

Then, leave the unit for several minutes or until the unit cools down before performing the maintenance. 

2. Disconnect Every Connection From The Gas Control Valve

Remove the bottom access panel or the outer door. Now, detach every connection like pilot tube, igniter wire, and manifold tube from the gas control valve. 

You should use a 7/16” wrench to unscrew the pilot tube. On the other hand, the manifold tube requires a ¾” wrench to remove it.

To disconnect thermocouple wire, use needle nose pliers. Make sure you don’t kink the pilot tube while removing it from the gas control valve. 

3. Remove The Burner Assembly Out of The Combustion Chamber

Remove the screws that hold the burner door or the burner assembly in place. Once you unscrew the burner assembly, slide it out gently from the combustion chamber. Ensure you don’t damage any internal parts while pulling the burner assembly out of the burner chamber. 

4. Remove the Old Thermocouple & Replace It With A New One

Begin with removing the screw that secures the thermocouple assembly to the pilot bracket. Don’t forget to keep the screw in a safe place for reusing it later. 

Next, lift up the retainer clip from the back of the manifold component block from the manifold door. Make sure you don’t bend the pilot tube or change its position as it requires as a bending template for the new pilot or thermocouple assembly. 

Afterward, pull out the pilot/thermocouple assembly from the manifold assembly. Now, route the new pilot tube, new igniter wire, and thermocouple wire through the opening in the manifold door. 

Attach the new thermocouple assembly with the screw you removed earlier and reattach the burner to the manifold. Then, put the manifold component block back in the manifold door. 

Before moving to the next step, ensure you install the new brass ferrule nut in the gas control’s pilot tube opening. 

5. Reassemble Everything To Complete The Replacement Workflow

Finally, re-install the burner assembly into the combustion chamber. 

Next, make sure you reconnect everything like the pilot tube, igniter wire, thermocouple wires, and manifold tube with the gas control valve. 

After that, turn on the main gas supply valve and check those connections for leaks. You can use a solution of soap and water to check the leak. If the bubbles form up, I bet there is a leak. Otherwise, you are good to go. 

Before lighting and activating the water heater, be sure the tank is completely filled with water. 

FAQs

Are thermocouples for water heaters universal?

Most residential water heaters use 24” thermocouple. From this sense, we can say the thermocouple for water heaters are universal. But the best bait is to determine which size and style of thermocouple you will need for your water heater. 

Where is the thermocouple on a Reliance water heater?

The thermocouple on  a Reliance water heater is located inside the combustion chamber. To access the pilot/thermocouple, you must remove the bottom cover and the burner assembly from the unit. 

Can I replace the water heater thermocouple myself?

Yes, you can replace the water heater thermocouple by yourself by following the instructions I mentioned above. 

How do you light the pilot light on a reliance 606 water heater?

To light the pilot light on a Reliance 606 Water Heater, follow the below steps: 

• Set the gas control knob to the off position.
• Wait 5-10 minutes to allow the gas to clear out.
• Turn the gas control knob to the Pilot position.
• Press and hold down the gas control knob all the way in. 
• Keep pressing the igniter button while holding down the gas control knob. Continue to press the igniter button until the pilot light comes on. If the pilot light doesn’t come on, repeat the process again. If you fail to light the pilot after taking three attempts, turn the gas supply off and call a professional. 
• When the pilot light comes on, release the gas control knob and set the temperature knob to your desired temperature setting. 

Can you clean a thermocouple and make it work?

Sometimes cleaning the thermocouple will help you light the pilot. In this case, you need to use a fine-grit sandpaper to sand the thermocouple gently. If you fail to light the pilot after cleaning the thermocouple, you must replace the thermocouple. 

How much should a plumber charge to replace a thermocouple?

A plumber will charge $150 to replace a thermocouple professionally. But the price of a thermocouple is only $20. If you want to cut that price, make the replacement by yourself following the instructions I mentioned above. 

Can I bypass a thermocouple?

No, you can’t bypass a thermocouple. 

End-Note

Replacing the thermocouple on a Reliance Water Heater is not rocket science. Just follow the 5 simple steps I mentioned and replace the thermocouple without hiring a professional. It will save you up to $130. 

Read Also:

Reliance 606 Water Heater Troubleshooting