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 are the symptoms of a bad thermostat? bad thermostat housing symptoms.
What happens when a thermocouple goes out?
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 fix a bad thermocouple?
Thermocouples are designed to detect a pilot light’s loss of heat and close the gas valve to prevent a gas leak. Replacing a thermocouple is a relatively easy fix that can take less than two hours.
Does cleaning a thermocouple work?
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.
How do I reset my thermocouple?
Press the reset button on top of the box to turn on the pilot light. Hold the reset button between 30 to 60 seconds to give the thermocouple time to heat up. Release the button to see if the pilot light goes out. The pilot light should stay on after the reset.
How do you troubleshoot a thermocouple?
Place one test lead on the side of the thermocouple and the other to the end that screws into the gas valve. If the thermocouple has proper continuity, a small resistance reading should be visible on the multimeter. Many multimeters also indicate continuity with an audio alert.
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.
Will a pilot light on a thermocouple go bad?
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.
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.
How do you bypass a thermocouple?
- Move the tilts switch wire aside.
- Remove your thermocouple from the heater using an 8mm wrench.
- Pull the valve housing aside using your 13mm socket wrench. …
- Remove the valve using your pliers. …
- Put your thermocouple back into position.
Why does pilot keep going out on water heater?
Your thermocouple senses when your pilot light is burning. … If it senses that your water heater pilot light keeps going out, the thermocouple will shift off the gas supply to the heater. Over time, thermocouples can malfunction, accumulate dust buildup, or the device can get bent away from the pilot light’s flame.
How do you clean a thermocouple pilot light?
- Cut off the gas to your furnace. …
- Remove the pilot light and thermocouple assembly. …
- Use your pliers or wrench to remove the pilot light and thermocouple from the bracket.
- Using the wire brush, brush away the carbon buildup and soot from both components.
Why does my pilot light go out when I release the pilot light knob?
The most likely of those is that the thermocouple needs to be replaced. The button you press to light the pilot bypasses the thermocouple. When you release the button, the thermocouple ensures that unburned gas doesn’t get released by shutting off the gas when it’s not heated by the burning pilot light.
Why does my thermocouple keep going bad?
Changes in temperature can cause regular expansion and contraction in metal, which will cause thermocouples to weaken over time. After enough time, metal fatigue can cause a thermocouple to break. … If thermocouples start to give out unusual readings, it may be suffering from metal fatigue.
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.
How much is it to replace a thermocouple?
It costs $150 to $250 to replace a thermocouple. It checks to make sure the pilot light is on. It will shut the gas off if it’s not.
What does it mean when your pilot light won't stay lit?
If your pilot light won’t stay alight, it might be the thermocouple. Sometimes dust buildup collects on the thermocouple and blocks the sensor. Try cleaning the thermocouple and then relighting the pilot light. If it continues to go out, the thermocouple might need to be replaced.
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.
How many ohms should a thermocouple read?
A thermocouple should exhibit very low resistance. Attach the negative lead to the red wire, and the positive lead to the yellow. In this case, the reading will be about three ohms.
Do you smell gas when pilot light goes?
Pilot light safety is important to prevent fire or poisoning from natural gas the pilot burns. … If you smell the “rotten egg” odor of escaping gas, check to see if the pilot light is extinguished. If it is not, turn the gas valve to the “off” position and call your gas company.
What Colour should a pilot light flame be?
The color of the pilot light should be blue because that means that only natural gas—without any other condensates—is reaching the pilot light through the gas main. The principal chemical compound found in natural gas is methane, and methane burns blue.
Should the pilot light always be on in a gas heater?
Most furnaces with electronic ignition have a device called a hot surface igniter. … The difference is that the flame is only lit (by an electronic spark) when your furnace is ready for a heating cycle. When the pilot light is not needed, it is completely off, saving you money on gas.
Can a thermocouple fail 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.
Why is my pilot light so loud?
A – All control valves have a pilot adjustment screw. Turning it clockwise will reduce the flow of gas to the pilot. The optimum adjustment is just before the point it makes noise. … Another cause of excessive pilot noise is that the inlet pressure of the gas supply is too high.
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.
Are thermocouples interchangeable?
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.
How does a thermocouple work in 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 I clean the thermocouple on my gas logs?
- Turn off the fireplace gas valve and remove the front panel from the fireplace. …
- Find the thermocouple, which is located next to the pilot light and looks like a small straight pipe.
- Use a can of compressed air to gently blow away any dust and dirt from the thermocouple.
How long does a thermocouple last on a gas fireplace?
Although thermocouples can last several years, they don’t typically last as long as the furnace. It’s time to replace the thermocouple if the main furnace doesn’t stay lit. Most hardware and home improvement stores have replacements in stock.
Should the water heater be on pilot or on?
You should set the water heater to “pilot”. If, however, your water heater is also the boiler for your central heating, then you’ll want to leave the heating running as normal so that your house doesn’t get damp as a result of cold and condensation.
Do I need to turn gas off if pilot light goes out?
Since the thermocouple regulates gas going to the pilot, it should cut off on its own if the pilot ever goes out, but that’s only if it’s functioning correctly. If the thermocouple isn’t working properly, then it’s possible that it’s allowing gas to leak into the very room where the heater is located.
How many years does a water heater last?
It would be nice to know when the time is right to replace your water before it springs a leak and causes an inconvenience or worse yet, damage to your home. Typically a residential hot water heater lasts between 6 and 13 years. Beyond 12 years, you are on borrowed time!
How long will a thermocouple last?
In effect, new thermocouples were installed into contaminated tubes, causing the degradation of the sensors and generating greater than a 100°F shift in accuracy. In this scenario, thermocouple life, which should have been close to one year, was shortened to within a week.
