How to tell if a thermocouple is bad?
MultiMeter Thermocouple Test Procedure
- First, remove the thermocouple.
- Secondly, turn on the meter and set it to Ohms. ...
- Thirdly, start the flame and put the tip of the thermocouple in the fire.
- Next, ensuring the tip is nice and hot from the flame, take one lead from the meter and put it on the shaft of the thermocouple and the other lead ...
How do you change thermocouple on hot water heater?
Reestablish gas supply and test the unit.
- Disconnect the water heater’s gas supply.
- Remove the water heater’s burner assembly cover.
- Remove the water heater burner assembly.
- Remove the gasket from the manifold cover plate.
- Remove the old water heater thermocouple.
- Install the new water heater thermocouple.
- Reassemble the water heater burner unit.
What temperature should a hot water heater be set at?
Water heaters are factory set at OSHA recommended levels, around 140 degrees. On the other hand, the EPA suggests turning the thermostat down to 120 to reduce power consumption, and a booster heater to reach sanitizing temperatures at select outlets.
How to test a thermocouple?
- Method 1: Resistance Test. Carefully remove the faulty thermocouple from the gas appliance. ...
- Method 2: Open Circuit Test. In this test, the same setup as above will be used, but instead of measuring resistance, voltage generated by the thermocouple will be measured and ...
- Method 3: Closed Circuit Test. ...
How do you know if the thermocouple is bad on a hot water heater?
If the pilot lights but the flame goes out as soon as you release the button after holding it for 60 seconds, then the thermocouple is bad. It's possible to replace the thermocouple without removing the burner assembly, and many repair people do this.
What happens when thermocouple goes out?
Normally when the thermocouple malfunctions or isn't working, it simply shuts off the gas to your heater. This is important, particularly if the pilot light is out, because it prevents harmful gas from leaking into your home.
When should a thermocouple be replaced on a water heater?
Replacing a thermocouple becomes necessary when the pilot light won't stay lit even after the old thermocouple has been cleaned.
How do I know if my thermocouple is broken?
After about a minute, when you're sure the probe has gotten hot, place one lead on the shaft of the thermocouple and the other lead on the connector. If the reading is less than 25 millivolts, the thermocouple is bad and needs to be replaced.
Can you bypass a thermocouple on a water heater?
Realistically, you have just disabled the thermocouple, but you can also reach in and unclip it from its holding bracket where it meets the pilot light. In most cases it will be held on with a gravity clip, but some are held on with a screw that must be removed with a small screwdriver.
What causes thermocouple to fail?
After enough time, metal fatigue can cause a thermocouple to break. Thermocouples that are regularly exposed to extreme heat stress or extreme conditions are more likely to go through metal fatigue. If thermocouples start to give out unusual readings, it may be suffering from metal fatigue.
Can I replace a thermocouple myself?
It's easy to replace and a new one costs $5 to $10. Rather than trying to unfasten the thermocouple inside the water heater's burning chamber, it's easier to remove the whole burner and thermocouple assembly.
How much does it cost to replace a water heater thermocouple?
Thermocouple – $20 to $150 The thermocouple is an apparatus that senses whether the pilot light is lit and triggers the gas control valve. Repairs typically cost about $150 to have it done professionally, though a new thermocouple itself only costs about $20 on average.
How do you clean a dirty thermocouple on a water heater?
In cleaning a thermocouple, you need some steel wool or 60-grit sandpaper, and a cloth. First, turn off the gas supply, unscrew the thermocouple and then clean it with steel wool or sandpaper then wipe down with a cloth to remove residue. I clean our thermocouple every six months to avoid getting it coated with soot.
How long does a thermocouple last on a water heater?
How Long Should a Water Heater Thermocouple Last? If properly installed and maintained, thermocouples can last for up to 10 years.
How do you know when you need a new thermocouple?
A working thermocouple will give a reading of between 25 and 30 millimeters. If the reading is less than 25 millimeters, it should be replaced.
What is the most common thermocouple failure mode?
The most common failure mode for thermocouples is for them to fail open, this is known as thermocouple burnout. Burnout can result from a variety of reasons including the thermocouple experiencing a temperature in excess of that for which it was designed, metal fatigue, and oxidation.
Does gas still flow when pilot light goes out?
If your pilot light repeatedly goes out, this is a likely culprit. If this flame sensor should fail, gas will continue to flow even after the pilot light has been extinguished, causing a safety hazard and requiring immediate repair.
How do you bypass a thermocouple?
0:074:14Bypass thermocoupler on an outdoor patio heater - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo we're going to bypass thermocoupler by removing the spring valve inside of it. So we're gonnaMoreSo we're going to bypass thermocoupler by removing the spring valve inside of it. So we're gonna start by undoing yeah let's move the sparkler thing out of the way that doesn't work anymore.
How to remove thermocouple from gas valve?
Turn off the gas supply. Detach the thermocouple from the main gas valve by unscrewing the connection nut and copper lead, followed by the bracket nuts.
How Much Should a Plumber Charge to Replace a Thermocouple?
Generally, it will cost up to $150 for a professional plumber to come in and replace a thermocouple.
How Do You Know if You Have a Bad Thermocouple?
The first sign that you may have a bad thermocouple is that you cannot use heat or hot water because your furnace or water heater keeps going off. This indicates that something is wrong with your pilot light, and the thermocouple is part of the pilot light burner assembly. While it is possible that there is another reason for your pilot light issues, it could very well be a bad thermocouple.
Can You Bypass a Thermocouple on a Water Heater?
You can, but it is not necessarily a good idea. A thermocouple is kind of like a safety switch in that it prevents unburned natural gas from getting into your house when your pilot light goes out.
What Causes Thermocouple to Fail?
There are two main reasons why a thermocouple will fail over time: metal fatigue and oxidation.
What happens when you expose a thermocouple to oxygen?
The reaction between the metal and oxygen can wear down the wires in the faulty thermocouple, making them thin and brittle.
Why is it important to look at connectors?
Look at the connectors for damage. This is important because damaged connectors may yield inaccurate results of the open-circuit test.
What does a thermocouple do on a water heater?
When the pilot light in the water heater has a flame, the thermocouple reads that temperature. It keeps the line open. The opened line allows the gas to continue flowing, so your water heater continues to run.
What is a thermocouple made of?
A thermocouple is a kind of temperature sensor made up of two different metal wires. The ends join of these wires meet and join at one end were they create what we call a hot/electrical junction. The other ends of the wires pass through a gauge that reads millivolts and connects at the other end. The second junction they make is the cold junction.
What happens if a thermocouple is below 25?
If the multimeter records a millivoltage below 25, something is wrong. Your thermocouple either needs to be cleaned or be replaced.
What happens when a water heater is not heated?
If there is no flame or heat, the temperature of the water heater changes. It cools down. The thermocouple reacts to that change in temperature by shutting the gas off. You do not have to do it yourself.
What do you need to test a thermocouple?
To perform a test on your thermocouple, you need a multimeter and help from one other person.
What happens when a furnace sensor senses heat loss?
The same thing happens if you have a gas furnace. Once the sensor senses the heat loss, it cuts off the fuel supply.
Can you take care of thermocouple problems?
You can take care of all your thermocouple problems yourself. If you are not a Do-it-yourselfer, you need the help of a professional.
What is a Water Heater Thermocouple?
A water heater thermocouple is a sensor that turns off the gas supply when the pilot light goes out. This operational and safety feature is also known as a flame or heat sensor and its function is to control the flow of gas into the burner.
How Do You Know if Your Water Heater Thermocouple is Bad?
A bad thermocouple is the most common reason for a water heater pilot light that won’t stay lit. And it’s not unusual for it to wear out.
Final Thoughts
A gas water heater thermocouple replacement is a project you can do yourself. But it is important that you follow the safety rules: (1) turn off the gas is priority number one, and (2) don’t touch the thermocouple until it has cooled down.
Call 1-Tom-Plumber
Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need help safely maintaining, repairing, or replacing your gas water heater.
What is a thermocouple in a water heater?
The thermocouple is an essential safety feature of many gas-powered water heaters. It works like a temperature sensor that shuts off the gas supply to the burner if there is no heat in the pilot light.
How to prevent thermocouple from bending?
Apply firm pressure when twisting and pulling the thermocouple from its mount. It would be best to do this slowly to avoid deforming, bending, or damaging the thermocouple-pilot tube connection.
How far should a pilot flame engulf a thermocouple?
It is essential to place the thermocouple in the correct position. Ideally, the pilot flame should engulf the thermocouple’s upper half to 3/8 inch. If you do not position the thermocouple properly, your efforts to replace a thermocouple will be in vain.
Can you replace a thermocouple?
You need the correct thermocouple replacement for this activity. Unfortunately, you can only ensure you have the right replacement part by removing the old thermocouple and bringing it to the store.
Can I replace a water heater thermocouple?
Pro Tip: I advise you to bring the old water heater thermocouple to the store to buy the correct water heater thermocouple replacement. It will also be an excellent idea to consider buying a new manifold cover gasket if you intend to change the old one.
Introduction
A hot water heater that doesn't heat might just need a new thermocouple. Learn how to replace this inexpensive part and keep your hot water heater working for years to come.
Vacuum
This is a good time to vacuum out the burner compartment, check for water leaks and remove debris in the burner ports. Attach the thermocouple and reinstall the burner assembly. Light the pilot following the instructions on the water heater.
