How a Combination Gas Valve and Thermocouple Work!

[@acservicetechchannel]

Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Here is a link to the UEI DL389 Multimeter used in the videos- amzn.to/2av8s3q Here is the link to the Fieldpiece SDMN6 Dual Pressure Testing Manometer with Pump-amzn.to/2jyK5Ka Here is a link for the Supco Magnet Jumpers amzn.to/2gS4h6z Here is the link for the Irwin Wire Stripper/Cutter/Crimper amzn.to/2dGTj2V Other tool links can be found in the video description section. ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

[@jefflewis9154]

Hey, can you do a video on how to charge a Trane system in the winter time?

[@infiniti37G]

I diagnosed and replaced my gas valve after watching this video. Heat WORKS. Thanks

[@tiberio1352]

Dear friend, the on, off, pilot switch in my valve was very difficult to turn. So I put a few drops of silicone oil and it loosened up....Do you think I may have damaged the solenoid in any way??..... Please let me know.

[@realuniversechannel1]

What a nice video, in just 5 minutes you learn what others can't explain in one hour, thank you!

[@acservicetechchannel]

Thanks gersondaviduniverse!

[@400hpmustang]

Had a service call today where I was getting 20 mv at the thermocouple, the pilot would stay lit in the on position but when I called for heat I got nothing. Changed out the thermocouple problem solved, furnace worked like a champ. It was a Robertshaw gas valve 7c7-g8f-545, the slider type, set, pilot, on, off. Great videos, keep up the good work.

[@robinpaine161]

Superbly explained. Something that always puzzled me as I wasnt sure what the copper tube connection did. Thank you very much and joy of joys no stupid music!

[@acservicetechchannel]

Glad you enjoyed the video and found it informative!!

[@ThriftyToolShed]

Great explanation of the Thermocouple and gas valve. I liked how you took time to show the solenoid being held open. I always wanted to take one apart and see how that held in. They are so reliable I never had one to disassemble to learn with. I never have had one on my gas valves fail.

[@boghog6765]

Wow. I've been out of trades school for two years, and just moved to service from installs 4 months ago. Your videos are extremely helpful, i love the way you take the components out of the furnaces to isolate exactly what your talking about. Very simplified. The theory is spot on, the videos are quick and to the point. No other hvac youtube channel can even compare to yours. I love the refresher of some of these older concepts which i only learned first year of school and didn't really understand fully at the time. Thanks a lot for sharing this valuable information, it's helped me in my workplace!

[@acservicetechchannel]

Thank you very much for the note!

[@SquillyMon]

Excellent video...thank you so much for making it ! I had always pondered how such a low voltage could make a solenoid "open" the gas flow...Didn't seem to be enough electricity to energize a solenoid that had to open a gas valve junction to me. Your video allowed me to see what was right in front of me all along. WE are the ones who actually do the "heavy lifting" by pushing the pilot button / opening the gas valve. The tiny voltage to the solenoid only holds the gas connection open it doesn't actually open it by itself. Doh ! This explains a minor mystery I've held about the relationship of the thermocouple and solenoid for some time now. Thanks again !

[@leonardfennessy4825]

Great video. Helped me understand Thermocouples more than all the other places i seeked out the explanation. Thanks

[@acservicetechchannel]

Great to hear!

[@totalchaos444]

Thanks for the explanation. Changed my first thermocouple today.

[@1973jdmc]

Thank you so much for explaining concisely in 5mins what my lecturer couldn't do in 1hr- THANK YOU-

[@acservicetechchannel]

Thanks a lot, also check out "acservicetech Top 10 reasons the pilot light goes out" thanks

[@mountaintopjdog1131]

Perfect video, thank you very much. I was always curious how a gas valve works when a thermal coupler is part of the valve. Looks like I need a new solenoid. Fantastic job!

[@michaeldanon8343]

This was great. Thanks I finished my lvl 1 gas fitter class back in November and needed a refresh.

[@jonhenhapl2308]

Perfect!!!! Not too much not to little. No dogs barking in the back ground. A+ Thumbs up and subscribed...

[@tonyulriksen6532]

Just want to say what a great presentation video; learned all I needed to know about this simple yet elusive circuit.

[@acservicetechchannel]

Glad you enjoyed it!

[@fastlife866]

another simple yet great video. iv been doing heating for many years and just got into air conditioning last year and your videos helped me greatly, iv probably watched 90% of them. during the entire summer i only had an issue on one job. Keep making great videos 👍

[@acservicetechchannel]

Well glad to hear they are helping, thanks!

[@AndysDogHouse]

I am having trouble starting my shop furnace. The pilot light won't stay lit and now I know what to check. I subbed your channel to show my support and to say thanks for the help. Thanks for sharing.

[@jeffn31415]

This is exactly the video I was looking for, after dealing with a dirty thermocouple on my gas fireplace. Fixing it got me wondering exactly what is going on inside the manifold. It’s mind boggling that such a low DC voltage can keep a spring loaded valve open.

[@tonytubrick9394]

Thanks for that thorough explanation!

[@johnmcnamara4846]

Well explained. Simple and clear.

[@stephensomersify]

Just the detail that I was looking for! APPRECIATED old git, UK

[@TheMikeWash]

Great job with this video - GREAT explanation and demonstration!

[@acservicetechchannel]

Thanks Mike!

[@mohdahmed8400]

Thank you for sharing this instructive video

[@thanpan1276]

YOU ARE A BLESSING TO THE WORLD

[@vnesmuonnam]

fast, simple and easy to understand. Thank you

[@acservicetechchannel]

Thanks Minh Nguyen!

[@jitutalajia598]

Thank you very much for this video. It was very helpful.

[@acservicetechchannel]

Glad to hear that!

[@NLTSgym]

Thank you sir for continuing to educate all of us.

[@acservicetechchannel]

Thank you for your support!

[@Mars5826]

just watched your video enormous amount of practical knowledge keep up the good work thank you

[@acservicetechchannel]

Thanks Mario!

[@DanielImmanuel2143]

Excellent explanation

[@tvento]

Excellent presentation.

[@lancerudy9934]

Nice video thanks for doing all the training video.

[@acservicetechchannel]

Thanks Lance!

[@neverhobbyfree]

Thank you for making this great video!~ I hardly ever comment, but I had to since you have helped me greatly. After looking at countless other videos that don't actually teach the inner workings of the water heater, you sir have taught me how to fish! Once I understood how it worked (thanks to you!), ascertaining the problem and fixing it was a breeze. Once again, thank you.

[@acservicetechchannel]

Glad to help and thanks for taking the time to write this! I appreciate it!

[@andrewyek]

Thank you. I have being wonder how the gas thermocouple work.. i thought got some gas in the tiny copper vein that expand and push the valve to let gas flow.. Now i know it is generating mili DC volt to a mini solenoid.. Thanks

[@gobeyondnow]

I'm having this exact prob and suspected the thermocouple since it looks charred and rusted on the end next to the pilot. But my meter shows it is putting out about 14 mv which your video seems to suggest should be enough to hold the solenoid open? I'm not sure if that's correct and would appreciate a clarification as to whether I need more power. Meanwhile I'll look to see if you have a video about dismantling the solenoid from the control valve. Definitely appreciate this excellent video, thanks.

[@eman3208]

Thanks servicetech, have a good day man....

[@acservicetechchannel]

Thanks eman3208!

[@catherinemunroe3960]

very well explained ,thank you

[@wwindsunrain]

Very nice demonstration. Thank you.

[@acservicetechchannel]

Glad you enjoyed it!

[@jimbola77]

super very nice job thank you partner for sharing!!!!

[@acservicetechchannel]

Thanks jimbola77!

[@n24our]

I really enjoyed your video. Very informative and very to the point.

[@acservicetechchannel]

Glad you enjoyed it!

[@JoeMurphyLondon]

Lovely demonstration thanks

[@acservicetechchannel]

Thanks for watching!

[@ra8620]

You explained the best I replaced 4 of them then think needed to know how.

[@acservicetechchannel]

Thanks RA!

[@rayc1503]

So awesome seeing the inner workings of a multifunction gas valve. Stay blessed & keep up the great work. How do oxy pilots work?

[@awakenthemind-thenlpandhyp9301]

Nicely done video and explanation. Thank you! Is there a wide variety/different dc voltage thermocouples? I need to replace my gas fireplace thermocouple. Thanks.

[@acservicetechchannel]

Two different versions of the thermocouple at 30mv, one short and one long and a thermopile is 750mv. Match it up with what you already have, thanks

[@anonymous203020]

Genius explanation thank you

[@leehamilton98]

Great video 👍

[@acservicetechchannel]

Thanks for the visit

[@robertmorales4051]

What is the other wire for? The silver curled up one that’s to the left of the thermal coupler? Thanks

[@salam238]

Great work. Thanks

[@acservicetechchannel]

Glad you liked it!

[@jddr.jkindle9708]

Great explanation.

[@acservicetechchannel]

Thanks jd dr.jkindle!

[@x2malandy]

Yes sir, this is a good channel.

[@davidwong5476]

This is exactly how my radiant floor boiler works. After the pilot flame on, you are asked to hold the button for 60 seconds to allow gas flow, then release the button and switch the knob to ON

[@HamariAwaaz-in5so]

Can we buy this Solenoid? I have Blue Seal Gas Fryer G46. I have tried to find it online but unfortunately couldn't find anything. My pilot light is not staying on. Thermopile and thermocouple are working fine. Is there any help?

[@mark.r8900]

Hi, i hear a clicking sound from gas valve when thermostat calls for heat. But the pilot is off. Does this clicking sound means that the gas valve is being energized and gas is going to burner even though the pilot is off?

[@hhearst]

Very useful. Thanks

[@acservicetechchannel]

So nice of you

[@turkishburk]

That was super helpful! Thank you! (Signed: previously confused homeowner)

[@jeffreysquires1839]

how does the copper tube with inner copper part work? They function as two wires? How do they not short out? Thanks

[@MrFrozen73]

Great video !!! Very helpful videos you post.

[@acservicetechchannel]

Thanks Hvac_jc!

[@emiliomigliozzi294]

How many volts will open the solenoid because my flames are so low.? How do I know if its the solenoid or thermopile that is deffective?

[@path2049]

I have an old furnace. I tried to use this a few days ago. I turned the heater on via thermostat, and no warm air came out of the vent (but the fan was turning). I checked the pilot light and it was off. I re-lightened it (meaning gas was there). I turned the heater on again, with the same result. I checked the gas valve, TR and TH, 27V AC was there. Any suggestions? I tapped on it lightly as well, but no luck.

[@RB-nm3ko]

While set to PILOT, eventually the solenoid keeps the pilot light valve open. So what then does the ON setting do? I'm trying to follow how the ON valve is first but the pilot light valve opens first ? Thanks

[@DanO181919]

Another great vid!

[@acservicetechchannel]

Thanks Danny L.!

[@phamphoebe7642]

Hi, I have a problem with my gas furnace. The pilot is stayingn lit but it won't let me turn to ON position even I have wait for 10 mins. Please any advise

[@TheRealTonyCastillo]

So how does the thermocouple work for a blue flame propane garage heater that doesn't require power to run since there isn't any voltage to the gas valve? I was having issues with the pilot going out when the flame shut off. After cleaning the soot off the thermocouple gently by hand with a dremal wire wheel, there was also some soot where the gas comes out. My main concern was gas coming out of the heater when the pilot went out but after watching this video it appears that if the thermocouple isn't heated it will shut the gas off not allowing it to flow through the gas outlet by the igniter. Is that a fair assessment and understanding? This video was helpful.

[@acservicetechchannel]

Yes it is likely either a 30mv thermocouple or a 750mv thermopile. Look up "acservicetech thermocouple thermopile playlist" for more videos on them, thanks

[@justinm2037]

i too was confused how that little "dart tip"looking thingie could make electricity but it only needs to make just enough to make the internal coil a magnet its really neat i have a propane heater that has a tip over switch that interupts the thermocouple wire so i put one of those mechanical countdown timers in series with the tip over switch so it would turn off the heater after how ever long i set the timer for i might even try to add in a evergy star thermostats they were handing out trying to collect all the old mercury switch ones

[@dimitarm4668]

What should be the resistance of thermal couple coil valve?

[@ishalljr]

Great vid! So what makes the thermocouple go bad?

[@acservicetechchannel]

It is usually just the junction at the end failing over time.

[@ishalljr]

acservicetech that's what I was talking about. I was wondering why. Thanks

[@Pretzel114]

Nice video acservicetech! I think that is the first time I seen a operating cut away view of a combo gas valve. Boy I am getting behind on my video watching with you LOL! I am saving them in the the watch list. Hope you been doing well my friend.

[@acservicetechchannel]

I am doing pretty good. I feel like I am behind and there is so much I want to put out there and develop. I just do what I can for now! Thanks and nice to hear from you!

[@Pretzel114]

I think we are all glad for what you are able to share with us. I know I am. Don't over work yourself to much my friend. Thanks for everything.

[@mikemalone6103]

When the gas valve and pile has been replaced, what would cause the pilot to go out. High limit , spill switch …? I can understand if a HL opens main gas, but not the pilot?

[@stanleyanthony7822]

So interesting sir

[@-na-nomad6247]

why the 24 volts ? is it for the startup spark ?

[@thomassemich4627]

Thank you!

[@prettyboyplakio5013]

Would this affect if the whole unit would turn on and run?

[@prettyboyplakio5013]

If the gas valve had something wrong with it

[@ralphhardie7492]

Great thanks 😊

[@sundogaudio851]

does anyone know the model number of the Honeywell gas valve in this video? i need to buy a suitable replacement? thanks

[@jimkane9832]

I changed the thermocouple and valve but the pilot still goes out. It stays lit when I let off of the button but 30 minutes later everything is off. Any ideas?

[@vance12341234]

What is the most common reason a gas valve fails? Are there any 'temp fixes' that can be used to get someone by until the new valve arrives?

[@acservicetechchannel]

Unfortunately no they tend to be intermittently hung up inside

[@soundnstyl]

one time i was lighting my pilot and noticed gas actually coming out of the pilot button... what could that be??? do i replace the pilot button or the solenoid? what would i need to order?

[@soundnstyl]

also what is that specific gas valve you have there product number? if i just wanted to replace the entire thing?

[@ezazq9876]

Very helpful

[@acservicetechchannel]

Thanks ezaz q!

[@nwinter9859]

Can the outer coper wire of a furnace trhermocoupler be touching the gas line running along beside it ? How about if it is touching the furnace ? Could that prevent it from working properly ?

[@acservicetechchannel]

The outside of the copper is already touching the ground in multiple locations such as at the gas valve, the pilot termination area, etc but just the inner part connects to the solenoid in the gas valve so that shouldn't be a problem, thanks!

[@nwinter9859]

@@acservicetechchannel Thanks for the information. I had to replace the gas valve . Very interesting to watch how the themocoupler works on my old one . I can watch it activate the plunger when I hold a thermocouple to a flame. Amazing that the metals meeting can produce electricity when heated.

[@JacobKnightRiderShop]

So my garage heater wont start. It has a baso push button on it with a dial pilot nob seperaate from the button. Usually I push the baso button and it turns on. Now I push it and every now and then it wont start the furnace. Do you know what it could be?

[@acservicetechchannel]

Are you referring to the piezo spark ignitor? There may be soot stopping the arc, thanks

[@JacobKnightRiderShop]

@@acservicetechchannel no it's an old shop furnace it has no spark ignitor.

[@PaulHVAC1]

Well done!!

[@acservicetechchannel]

Thanks Paul HVAC!

[@justinm2037]

thanks for showing this i had a hard time understanding how just heat could make electricity enough to activate a solenoid but its only holding it doesn't pull it down i was thinking why not just have a nuclear rod surrounded by like a million thermocouples to generate power but in reality it only makes energy barely equivelant to a refridgerator magnet i wish you could have pulled it manually to see how much strength the thermocouple electromagnet force is actually there

[@acservicetechchannel]

Thanks Justin, yeah this video was just an explanation on how the combination valve and thermocouple work together. Many people don't even realize what a solenoid is so I wanted to show it, thanks

[@phillipjoy8191]

Great videos

[@acservicetechchannel]

Thanks Phillip Joy!

[@mark.r8900]

hi, can you please tell me how i would connect the 24v transformer and the thermostat wires on this gas valve? thank you.

[@acservicetechchannel]

TH is power 24v and TR is common 24v , the TH/TR is a common tap that is not connected into the gas valve. It is just there to connect hot wires together if desired, thanks

[@dustinthewind5538]

Another great video! I was wondering if you could do a video on the honeywell smart gas valve with 24V intermittent pilot ignition. I was servicing some older airco furnaces that had this setup. Just want to learn more.

[@dustinthewind5538]

I should have said 24V intermittent hot surface ignition

[@acservicetechchannel]

Yes I made one, check out the Gas Furnace ignitor troubleshooting playlist - kzbin.info/www/bejne/p5vVo4ujgdF_iMU

[@dustinthewind5538]

acservicetech Oh awesome. I should have checked before I asked.

[@acservicetechchannel]

That's ok. I'm trying to get the word out to travel the channel through the playlists. Thanks

[@Gameboy_Steve]

Thank you

[@abdulh63]

thanks!

[@rocker8692]

so the pilot lights the main burners?

[@acservicetechchannel]

Yes that is correct. Thanks

[@greenhornetbandit5437]

hey just a quick question what certificate or test would I need to do to work within air conditioning and refrigeration in America I'm planning to move to America in England I have a F gas certificate level 2

[@acservicetechchannel]

Really it is the EPA 608 universal refrigerant license. To own your own business you may need to have a state HVACR Master license though depending on the state. Here in New Jersey we have to have an HVACR Master license but just to work under someone with a license you just need the EPA 608. The link is at www.acservicetech.com

[@greenhornetbandit5437]

acservicetech I did see the EPA 608 universal on Google but just wanted to make sure as I watch your videos I thought it was best to ask a professional thanks you for the information and the link

[@acservicetechchannel]

Glad to help!

[@TheSkoto1]

Lenox hanging shop furnace, my pilot will say lite until I go to turn on the gas and then it goes out??

[@acservicetechchannel]

That sounds like low gas pressure. Is the tank empty if it is propane?

[@TheSkoto1]

@@acservicetechchannel natural gas off the city line

[@INTERNA9]

THANX

[@May-yv2kq]

can i say thank you so much.

[@acservicetechchannel]

Thank you May24, glad to help!

[@BYENZER]

Here's a trick gas company techs use to clean thermopiles/thermocouples WITHOUT REMOVING them, NOR using any abrasive, in under 2 min: 1. After pilot light is lit, continue to hold PILOT LIGHT BUTTON ON, and DO NOT LET IT GO. 2. Allow thermo to get full HOT. (Continue holding pilot button). 3. SQUIRT bottle water stream shots (2) at the thermopile ONLY. Avoid the pilot flame. 1st shot fractures, (via THERMO-SHOCK temperature change), all the carbonized crud that has accreated upon the thermopile body. 2nd shot rinses it away. 4. Repeat, until most all the crud is gone. DONE. 5. Collect your "He Da Man" points!

[@jagrench62]

What if there is no flow when you push button.

[@trueflamexp7297]

If that solenoid fails to close with the pilot flame out (doesnt click back into position) it is now a safety concern due to a failed valve. Just a heads up to you diy's.

[@LivPoxleitner]

my pilot stays lit but i cant turn it to on. it gets stuck at pilot! then eventually the pilot goes out..

[@acservicetechchannel]

What mv are you getting when you test the thermocouple?

[@arthurharrison1345]

Given a coil resistance of 100 ohms, the amount of power required to keep the solenoid activated is only .03 volts^2 / 100 which is only 9 microwatts. That's amazing, and almost doesn't seem possible.

[@acservicetechchannel]

You need to think, it is only holding it up, it is not applying additional force upwards to keep an electrical contact tightly secured such as in the case of a contactor or fan relay. It is just providing a pathway for gas to go through but yeah quite small amount of power, thanks!

[@cheshzone5281]

Next time use a torch lighter ........ fast and efficient ...

[@ValMartinIreland]

How can 30 millivolts have enough power to pull that spring back to open.

[@drewlarson65]

saying "DC millivolts" makes you sound like you don't understand electronics fyi, voltage x amperage = power(watts), amps make the force experienced by the solenoid windings. try milliwatts ;)

[@acservicetechchannel]

I say that to my students and in this video so they know what setting to set the multimeter to and yes the power law is the basis for everything we do, thanks

[@saeedhameed9148]

Very well explained thanks

[@acservicetechchannel]

Thanks Saeed!

[@BlackJesus8463]

Thank you!

[@acservicetechchannel]

Glad to help!

[@mc20855]

thank you

[@acservicetechchannel]

Thanks mc20855!