How does a thermocouple work on a gas valve?

How does a thermocouple work on a gas valve?

The thermocouple responds to changes in temperature by producing an electrical current that causes the gas valve that supplies the pilot light to open when the temperature is high or to close when there is no direct heat source.

How does a thermocouple provide pilot safety?

The thermocouple detects the heat from the pilot light, and should the pilot light go out accidentally, the thermocouple will automatically shut off the gas valve. This prevents unburned gas from flooding into the combustion chamber, where a small spark might cause an explosion.

What opens the safety valve on an oven standing pilot gas burner?

Direct Spark On some ranges, an electric spark directly ignites the oven burner. When the thermostat wants heat, it opens the gas valve and sends an electric spark to ignite the burner. If there’s no ignition after two attempts, the oven burner is locked out.

How does a gas oven safety valve work?

Electrical resistance from the glow bar blocks current to the gas valve, making sure that the valve closes. This decreases as the temperature increases. When the bar reaches a particular heat, enough to ignite the gas, it allows sufficient electricity through to open the gas valve.

How do you test a thermocouple on a gas valve?

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.

How does a solenoid gas valve work?

Gas Solenoid Valves are made of parts that receive electrical impulses that then translate those impulses into mechanical movements. When an electrical impulse is received, by the Gas Solenoid Valve, it will open or close the valve. Thus controlling the flow of gas into a chamber or through a line.

Does the thermocouple open a solenoid valve or hold a solenoid valve open?

A thermocouple is a type of flame safety that prevents the gas valve from dispensing the gas into the burners without the presence of a flame. If the flame goes out, the solenoid will close and stop the flow of gas as the thermocouple will not generate the amount of voltage (millivolts) to hold it open.

Does a thermocouple need to be in the flame?

Typically the thermocouple sensor is mounted right in the flame of the pilot light on gas fired heating equipment. But not all of these systems use a thermocouple. Some gas fired heating equipment relies on an electronic ignition to ignite the flame. Those devices generally will not use a thermocouple.

How does a thermocouple keep gas from flowing into the oven?

That current is used to hold a small valve open, allowing gas to flow freely into the appliance. If the pilot flame is extinguished for any reason, the probe cools, which interrupts the electrical current that was holding the valve open. As a result, the valve closes and prevents gas from flowing into the oven.

How does a thermocouple / millivolt gas valve work?

If there is no electrical power being supplied then it is probably a diaphragm valve with a tiny pilot valve where the pressure of the fluid itself is what actuates the valve. If there is no fluid pressure the valve will not open. The thermocouple only supplies a tiny amount of power, in the mW range.

What to do if your oven thermocouple is broken?

If your oven thermocouple is broken or faulty, it’s extremely important that you replace it ASAP. You can buy a new thermocouple here. The key part of the thermocouple is a probe that sits close to your oven’s pilot flame.

How does a thermocouple work in a washer?

The Wikipedia article explains it quite well. The main valve is actuated by the pressure of the fluid itself and the electric signal controls a very small pilot valve. Water valves for washers work on the same principle. Thermocouples might give some voltage in open circuit but that falls when in-circuit.