The No. 1 cause of pilot lights that won’t stay lit is a worn-out thermocouple. 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 a plumber charge to replace a thermocouple?

Calling a professional plumber to install a new thermocouple should only be up to $150. If you do the work yourself, you will only pay the price of the part which is about $20. The thermocouple is responsible for sensing that the pilot light is lit and triggering the gas control valve to continue providing gas.

How long do thermocouples last?

Thermocouples can last up to 10 years if properly installed and maintained, while furnaces can last 15-20 years, although either may wear out sooner in multifamily units.

How do you know if you have a bad thermocouple?

If you can’t get the flame to light at all, and you’re sure the gas is on, there’s probably an obstruction in the pilot tube. If the flame lights and goes out when you release the gas control knob after holding it in for the recommended 20 to 30 seconds, that’s the sign of a thermocouple malfunction.

What causes a thermocouple to go bad?

The presence of oxygen causes a reaction in the thermocouple that can wear down the part and make the wires become thinner and more brittle. Oxidation can be caused by a small amount of oxygen making its way into a sealed environment and reacting with the pure metal of the thermocouple.

Can you clean a thermocouple?

Yes, you can clean a thermocouple, but the task must be done with a light touch. Remove the thermocouple from the process assembly, using a steel wool or emery cloth, lightly clean the tip removing any build up.

What do I do if my pilot light keeps going out?

Once The Flame Is Lit, Turn Gas Control Valve to “On” Once the pilot light is ignited, you can release the reset button after 30 seconds and turn the gas knob to the “On” position. At this time you should hear the main burner come on. Now your pilot light should hold a flame and hot water should be restored!

What happens if a thermocouple fails?

If the appliance has a thermocouple, the problem may be a faulty thermocouple. The thermocouple, which operates as a safety device, turns the gas supply off when the pilot light goes out. … When a thermocouple fails, the pilot light won’t stay lighted. A burned out or broken thermocouple should be replaced.

Can you bypass thermocouple?

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.

Are thermocouples universal?

Honeywell, White Rodgers, and other manufacturers make universal replacement thermocouples, usually with a 30-millivolts (mV) rating for standing-pilot furnaces. … Electronic flame sensors are much less universal, and you must find the exact part specified for your furnace model.

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What size thermocouple do I need?

Universal thermocouples come in lengths from 15 to 36 inches. An 18 or 24 inch will suffice for all residential water heaters using universal kits. Almost all older waters heaters and many of the newer style units with a sealed burner compartment and a viewing window will use this thermocouple.

How do you clean a dirty thermocouple?

The best way to clean your thermocouple is to use either a piece of steel wool or the coarse side of a sponge to gently clean off any soot or other remnants. You can use a pencil eraser to clean between the threads of the screw that connects the thermocouple to the control valve of your system.

Can you damage a thermocouple?

Like the other component parts in your furnace, the thermocouple can wear down over time, producing lower voltage than it should when heated. And the worst part is that you can have a bad thermocouple without even knowing. Therefore, inspecting and testing your thermocouple should be part of your furnace maintenance.

Should the pilot light always be on in a gas heater?

Leaving the gas on keeps this compound moving out of the tubes. Keeping the pilot light on will also keep moisture out of the unit and in turn, help prevent corrosion. … As you can see, it’s probably best in most cases to extinguish the pilot light in your gas fireplace during the months when you don’t need heat.

Will a pilot light stay lit with a bad thermocouple?

A thermocouple senses the heat of the pilot and allows gas to flow to the burner. A bad thermocouple will shut off gas to both the pilot and the burner so the pilot light won’t stay lit.

How much does it cost to replace a thermocouple UK?

Although a replacement thermocouple is an inexpensive part, the cost for a boiler engineer to fit it is likely to bring your boiler’s thermocouple replacement to approximately £150.

Should thermocouple be in pilot flame?

The pilot flame should touch the thermocouple at a specific level. If the flame is blue and weak, and barely reaches the thermocouple, it needs to be stronger. If it extends well above the thermocouple, it’s too strong. … Install a new thermocouple by screwing it in, heating it up a bit, and then lighting the pilot.

How do you fix a gas fire that keeps going out?

1. Before You Begin: Is Your Pilot Light Lit Inside Fireplace?
2. The Fix: Pilot Light to Gas Fireplace Won’t Stay Lit.
3. Check Your Thermopile Output with the TH/TP Contacts.
4. Don’t Replace Your Thermopile or Thermocouple Right Away.
5. Cleaning the Thermopile.
6. Re-test the Cleaned Thermopile.

Can a thermocouple work intermittently?

In electrical circuits, the most unreliable points are electrical connections. So, if in a thermocouple circuit any of the connections suffer from corrosion or lack of intimate metal-to-metal contact, intermittent operation will result.

Is a flame sensor and thermocouple the same thing?

People tend to use the terms “flame sensor” and “thermocouple” interchangeably. In truth, while they basically perform the same job, they’re not the same thing. If your furnace uses an electronic controller, it’s got a flame sensor. Thermocouples are used on standing pilot furnaces that have pilot lights.

Why won't the pilot stay lit on my wall heater?

The Pilot Won’t Stay Lit A pilot that won’t stay lit could be the result of a blockage in the pilot tube. Turn off the gas, clear the tube with compressed air, and relight the pilot. If that doesn’t work, you may need to call a repairman to come and install a new thermocouple.

How does a thermocouple work on a patio heater?

The thermocouple of a gas patio heater is a safety component designed to prevent gas leaks when the pilot goes out. It’s a copper rod that sits next to the pilot tube on the other side of the spark igniter; it allows gas to flow through the pilot tube when it detects heat from the pilot light.

How do you jump a thermocouple?

1. Move the tilts switch wire aside.
2. Remove your thermocouple from the heater using an 8mm wrench.
3. Pull the valve housing aside using your 13mm socket wrench. …
4. Remove the valve using your pliers. …
5. Put your thermocouple back into position.

How many volts does a thermocouple produce?

A single thermocouple (C Type) is used for a standing pilot system and generally produces around 30 millivolts. This voltage is used by the gas valve to keep the pilot valve solenoid internal to the main gas valve open.

Can a thermocouple leak gas?

The thermocouple regulates the flow of gas to the furnace. … In a few cases, a malfunctioning thermocouple may allow gas to leak into your home, which is a major problem. That’s why, when you detect problems with your thermocouple, you should turn off the gas immediately before calling in an expert to help.

Can a thermocouple short out?

The temperature is converted by the controller or pyrometer. There are two wires connecting the thermocouple to the controller. If the lead wires touch at a bare spot where the insulation has worn off or is stripped back too much, they will short out.

Why does my gas logs keep going out?

Drip Loop: moisture in the gas line can cause a failure in the drip loop. This could be the reason why your fireplace won’t stay lit. Moisture can dilute the natural gas, so you’ll want to have a professional see if this is the problem at hand.

Can you buy a thermocouple?

Universal thermocouples, as the name implies work on most water heaters. They are available online and in home supply stores for a reasonable cost. The length and the thread type are the two concerns when purchasing one.

Are all thermocouples the same?

Commercial thermocouples are interchangeable, economical, and supplied with standard connectors. Unlike most other temperature measurement devices, external form of excitation is not required for thermocouples because they are self-powered.

What happens if my thermocouple is too long?

Thermocouple cannot have kinks, but copper can be rolled if thermocouple is too long. … The electromagnet holds open the safety valve as long as the pilot flame is heating the thermocouple. If the pilot light is out, the electromagnet closesa valve, and no gas can enter gas contrtol.

Are Thermopiles universal?

Product Overview It’s easy to install and designed for use with your gas- and propane-fueled appliances. It features a universal fit that can conveniently replace Honeywell, Robertshaw, Jade, and General Controls cartridges.