HVAC: What Is A THERMOCOUPLE & How Does It Work? (Basic Working Principal) How It Works

Nice and concise. Thank you.

You explained what a thermocouple does, but did not explain how dissimilar Metals produce DC voltage

THANKS!

Why doesn't the copper tube need insulating? Is the generated electricity conducted by the copper tube?

So this is not actually how the thermocouple works but rather how a thermocouple works in an HVAC system. There's a difference between a thermopile and a thermocouple.

Excellent work, good video footage and voice projection.

Educational , thumbs ,up

Very informative and detailed tutorial.I will be subscribing and checking out your other videos.👏👏👏👏

What would cause a thermocouple to corrode and blow up at the tip so fast?

Thank you so much for this!!!

No, you get this totally wrong. You claim this works via electricity - which is true only for electronic metallic strip measurement thermocouples connected to a voltage meter.

This control type of thermocouple works simply by heat expansion pushing the rod out of the end of the thermocouple to keep the gas valve open while hot.

You can demonstrate this to yourself simply by telling a new thermocouple and heating the sensing end while watching the rod at the far end come out.

Please delete your voiceover to this otherwise excellent video and rerecord it.

Very good description. Is there anything inside the tubing for the thermal couple?

bud do i need to have a special gas valve ?

well said! Thank you !

You forgot to say that the 30 millivolts is an open circuit reading and not a closed circuit reading. Closed circuit is when it is connected to the gas valve and will be lower.

Very good helpful thank you

I came here for a simple explanation and that is exactly what I got. Great job. I didn't want a 40 minute video. Short and sweet.

Tyvm!! Very clear and concise. You’re a good teacher friend!

❤

Thanks 🙏

Very good explanation...I'm new to the HVAC industry and this was top notch informative and know I clearly know what a thermocouple is thx to your time and work.... thank you

Like-verygood right to the point

Very nice video. I have blue seal deep twintank fryer GT46. It is fitted with both thermopile and and thermopile with it gas vales. One of the fryer's pilot is not staying on. When I leave the pilot holding knob, the pilot switches off. I have checked both thermopile and thermo couple. Both are working fine. Please can you advice what else can be wrong? Is that mean the main gas valve has gone? Or any solenoid in the valve has stopped working? Can we replace solenoid or the whole valve needs replacing?

Thank you for explaining

Very good thank you

The Thermocouple copper tubing has wire running down its center (Usualy with high temperature insulation surounding it) somewhat like coax wire used for TV signals the copper tubbing connects one side of the circut, the wire inside the other.. the connector on the gas valve has an insultated central contact , and this is connected to small electromagnet in the gas valve safety system that will only allow the gas valve to supply gas "if" current is being generated from the thermocouple being heated from active pilot flame ,, lose the flame you lose the milivolt current driving the electromagnet and gas valve closes..its safety operation must be proven. blow out the pilot and its gas flow "must" stop in under 45 seconds. if it does not close the gas feeder valve feeding the applience and red tag it Do not operate until inspected by a licenced Gas techician .. you have a faulty gas valve that must be replaced by a licenced gas technician. some gas appliences also have a second Thermopyle generator that also uses the pilots heat to generate a higher voltage around 300 Milivolts that is capable of opening the main gas valve. without the need for power from the power grid..

Thanks for the explanation, it was very helpful

Great video

should thermocouple's tip burn red hot during the furnace on or pilot frame?

great video thanks

Thanks for the explanation. Would have been nice to see you light it. though

seems like such a tiny voltage to operate an electromagnetic valve to open or shut down a big volume gas pipe. 30 milivolts? is that .03 of a volt? and at how much miliamps? seems like such micro power. this tiny charge doesn't go to a powered valve, this small charges operates the valve...wow...how? so weak

Loved the video..

Quick question thou....

Does the pilot button allow gas to bypass and flow to delight it?

Thank u

Thank you

Thanks for this valuable info

Thank you

As one side of the thermocouple metal warms up, wouldn't the opposite side soon warm up due to conduction and therefore reduce the current needed to induct the solenoid? Thanks

That was really clear.

Good content !

Excellent explanation and video!! I found it because we were having trouble with our pilot light, which explains a lot, as well as the primary fix. What would also be helpful to learn is what happens to an aging thermocouple. Ours seems to be disintegrating — supposing this is due to 6years of constant heat, but that seems unfortunate given its designed use.

My thermocouple when heated is giving about 26mV but not engaging the magnetic safety valve even if you press the valve. Could the magnetic valve be mismatched with the thermocouple from factory? Which magnetic valve works on 26mV?

What ignites the gas in the burner tube? I thought this is what the pilot was for.

How about when it doesn't work?

Thank you!!! Your explanation of the different parts as well as what they do and why was very informative. I hate videos that talk over your head or speak to the watchers like we are Master Electricians (Or whatever the experts are called). LOL. Thank you again!!!

Thanks for the great video!
Just a question.
What happens when you use a thermocouple with a PID heat controller to use it to determine set point whether to turn a induction heater element on and off if the thermocouple breaks down and the PID controller reads zero celsius? Does the PID shuts off automatically or does it keep trying to heat u the element in order to reach the program heat set point?

im actually a tech myself but not very experienced in heating. my gas valve solenoid kicks in and out constantly on a williamson boiler. i verified 24v from trans to module. then from module to valve. i dont see a pilot on the boiler i think it just utilizes a spark control. im guessing its the valve itself. any ideas?

Video was very informative - much thanks for taking the time to assist us!

what causes a thermocouple to fail/ I have put over 6 thermocouples in the past 2 years in my furnace.

Great Video. Question Please: The bracket (shown in your video) showing the thermocouple bulb and pilot light bonnet .....Where can I get one of those. My Burnham gas boiler has that assembly welded to one of the flame tubes. The problem I am having is the old thermocouple used an aluminum nut assembly that screwed into the thermocouple bulb holder and it twisted off. I managed to cut the old thermocouple and drilled carefully, but I can't remove the aluminum piece that remains inside. I am afraid of going any further because I risk ruining the inside threads or distorting the hole that the bulb is mounted into. Right now, I am using the clip that comes with the thermocouple kit to fit over the bulb and hold it in place. Might you have any suggestions? Thanks

I want to know how to bypass the thermocouple

Thanks for your explanation.