Wednesday, December 23, 2015

How does a thermocouple work on a gas valve

Light the pilot by pressing and holding the pilot light button on the gas control valve. A gas thermocouple works by creating a small amount of electricity that is sufficient enough to keep open the part of the gas valve that lights the pilot assembly. It acts essentially as a sensor which is connected to the main control valve. A gas furnace thermocouple is a solenoid valve that operates off heat instead of electricity.


The thermocouple works in conjunction with the pilot light and the main gas valve. The valve is located in the pilot assembly.

A cooker either has FFDs or doesnt, they are not to my knowledge a retrofit item as it would be a non approved modification to a gas appliance so would be illegal and would. As others have said the Baxi heats a cylinder that stores the hot water, In comparison with a high tec condensing combi the humble Baxi Bermuda, unless it one of the later models will have a pilot light with thermocouple a gas valve and a. This prevents unburned gas from flooding into the combustion chamber, where a small spark might cause an explosion. I show you the exact part in the gas valve that keeps. Universal ones from ebay £not the manafactures £3 but no joy.


The current actuates a spring mechanism on the gas valve that keeps the valve open. A bad thermocouple itself can prevent a gas furnace or boiler from working - if you can light the flame at the pilot manually but then the flame goes out when you release the manual gas feed valve , the thermocouple is probably bad. This valve is used in many gas appliances.

I show how the thermocouple works and how it is used to keep the unit from running without a pilot flame. I also discuss the regulator and how to adjust it. While replacement of a thermocouple is simple, DIY work with gas systems can be dangerous. If you choose to procee take note of the model and the listed replacement parts.


You can test one by disconnecting it from the gas valve and measuring the. A thermocouple is a sensor for measuring temperature. This sensor consists of two dissimilar metal wires, joined at one en and connected to a thermocouple. Some times you can just relight the pilot and it will hold for a few days then go. If the pilot goes out, the thermocouple can no longer send the millivoltage that is required to allow the gas valve to stay open, thus sealing the valve to prevent a dangerous gas leak.


The gas water heater thermocouple is a safety device. It senses when the pilot light is on. When the pilot is not lit the gas valve will not turn the gas on.


It is composed of at least two metals joint together to form two junctions. One is connected to a body of known temperature, while the other is connected to a body of unknown temperature. This enables us to measure the temperature of the unknown body by comparing it to the known.


The tip of the thermocouple is placed in the pilot flame, generating a voltage which operates the supply valve which feeds gas to the pilot. So long as the pilot flame remains lit, the thermocouple remains hot, and the pilot gas valve is held open.

If the pilot light goes out, the thermocouple temperature falls, causing the voltage across the thermocouple to drop and the valve to close. Turn the valve so that it sits perpendicular to the pipe. Bad Thermocouple or gas valve I have a Burnham Series 2Gas Boiler, Pilot went out and will not stay on after I hold down the button for pilot gas. I have about 17mv at the end of the thermocouple after holding pilot for approx. If the gas valve works fine when the spare thermocouple is being heated by the lighter, you need to replace the old thermocouple or thermopile.


In this way, the fire place can be turned on, turned up, turned down and shut off with just the turn of a switch even without external electric power being supplied to it.

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