Thank you for your nicely shot vids! Very helpful in understanding my ancient system :-)

Great video, actual demonstration with meter.

Great video... You can also mention later on that on mv systems, you need a mv thermostat, you cannot hook up a 24 volt thermostat to a mv system. I have not seen that many thermo piles out there, except for old gravity furnaces and occasionally on older boilers.

Thank you for the info. I didn't understand the difference between the two until now.

Finally got it working thanks for all your help

Nice video Gray.

Thank you Sir! I learned a lot!

Originally, they came with wires. The reason they are made the way they are is it makes better contact and can be differentiated from a thermopile. The bare tubing is actually one wire. The other is the insulated wire inside. Hope this helps. GFM

Found the problem. After changing out the the pilot assembly the start up was fine, however when the fireplace was lit the pilot was slightly starved of gas. The pilot flame wasn't as pronounced and the piezo igniter was splitting the flame. So the thermocouple wasn't getting sufficient flame. I bent the igniter down and over a bit allowing a full flame on the thermocouple, thus solving the the problem. Thanks for your video and response. It definitely helped with the change out.

I have a fireplace insert that started turning on by itself. There is a wall mounted millivolt switch with a pilot light. What steps can I take to find the source of my problem before calling for service? It is a Heat n Glow model ROLS -18N. Thanks in advance.

Great video

What's the solenoid current required for holding the pilot valve? The thermocouple output voltage is only 30mV!

Dude ! This is exactly what I was looking for. Grandfather was a plumber so my father taught me. Father worked in electronics so he taught me. I was confused though because my gas fireplace has both. Now I even know how to test them. Way Cool ! And at 70, i'm prob way older than you ! LOL Thanks.

Really enjoyed this clip=THX!

Thanks for the knowledge

Good video. Why doesn't the thermocouple just have wires like the thermopile. I never could figure out why the thermocouple has the bare copper tubing.

interesting vid, thanks for posting

+GFM I have an outdoor thermometer, simply for outdoor temp readings while getting dressed in the morning. I have placed it out of the shade every way I can think of, but I am still getting false readings because of the sun. I have tried wrapping the thermocouple in aluminum foil and I have tried shading it even more so than it already is. I have tried tucking it beneath the vinyl siding, but still get false readings. the digital display is accurate at night and in a cup of ice water. do you have any thoughts on how to prevent false measurements? I am limited to about 10' of wire between the display and the thermocouple. thanks

Hi GrayFurnaceMan, I have a 35+ year old gas furnace (Howard Southwind) with a standing pilot light. Furnace works well when running but has intermittent ignition troubles and has taken as long as 30 minutes to start - other times it fires up right away. The worst offending time would be morning when the furnace has been off for the night. The pilot light is always on and is nice and blue. I thought it was the thermostat but have tried 2 other thermostats and the problem persists. Because it is intermittent I thought that the new thermostat was fixing the problem. Inside the furnace the gas valve box has 4 wire screw terminals. It appears that two of them are attached to a thermopile…it has silver coated wire and two clips on the end with a white and red wire. The silver wire runs down to the pilot with a tube threaded into place. I put my multi-meter on the terminals and have a reading of 132 mv while the burners are on full. With the pilot light still on but the burners off…the reading is between 194 and 162 mv. It is difficult to get a solid reading off of the screws themselves. I also tightened the screws. Besides the main gas burner pipe there is another small aluminum tube that runs out of the gas valve box and down to the pilot light. I am not sure if that is also a thermocouple. If I replace the thermopile - how do I know which one to buy? (When I went online to research gas furnace thermopiles almost everything relates back to thermocouples and most images do not have the wires…which my furnace obviously uses. I also see the K type mentioned….but I am not sure what part to order from my HVAC supplier) Most suppliers want to know furnace make and model naturally and here is no literature or manual available for my Furnace. I like my old furnace it has been chugging along perfectly for the last 20 years…the heat exchanger looks good, I recently replaced the blower motor and belt as well as the fan relay switch and filter as part of the maintenance. Thanks for any advice!

Thanks. Sounds like a thermopile is a battery of thermocouples in series.

good one, thanks...

Thanks GFM

I need a thermopile for a small gas booster heater. The current one works well enough to run the pilot safety, but not enough output for the thermostat circuit. Local places around here don't have them (most don't seem to have heard of them). You've shown that they are still being made, can you tell me where in the H*!! to get one?

While the pilot on my Vermont Castings direct vent gas fireplace stays reliably lit, the flame isn't. It goes out after being lit and the time it is fully burning is shortening. I cleaned the unit and two thermopiles, had the unit inspected and it was determined I needed two new thermopiles. They wanted $1,000 for parts plus labor. I purchased two thermopile thermogenerators. Can I install these myself or should I use a gas fitter? I noticed that the wires for the thermopiles pass through a red rubbery sealant. What is this?

I will let u know how I make out this week thanks for your time patience

Thank you, Sir.

My 1999 LP gas Xtrordinair Gas Fireplace takes several minutes sometimes 1/2 hour for the gas valve to open and function when the thermostat is calling for heat, is that a case of a bad thermopile? So called service technicians only seem to come in a replacing everything for $$$ until it works which has happened too many times over the years.

I have a Heat-n-Glow gas fireplace with a hard wired wall thermostat. It worked fine with the thermostat but now it will not turn the flame on, however, by manually turning the fireplace on and adjusting the temperature up, it will stay on just long enough for the fan to kick on. It then cycles back off without ever coming close to the set room temperature. Thermopile issue?

I have a 90 model floor furnace. Pilot light stays light. Changed relays and thermostat. Still will on come on.Any suggestions?

I have a DESA natural gas fireplace. My thermocouple works great because the pilot light stays on when I turn the gas to the on position, but the pilot light goes out when I turn my thermostat on. The thermopile gets up to about 460 millivotes with no load. When I connect it to the gas valve and turn my thermostat on, the pilot light immediately goes out. Do you have and suggestions on hoe to resolve this problem?

Is the 292 mv enough to pull a gas valve soloniod ? Also is the 30 mv for a thermocouple big enough to pull a solonoid for a gas heater valve to let gas go through ? Thanks for your good video

Hi. I have a 14 year old commercial oven in a restaurant. Pilot light would turn on and turn off. I inspected the pilot light on the burner . Found the thermocouple or pile wiring broken, flame was on it. Replaced the thermocouple. Question is do I have to rest the pilot at the controller. Thanks

Gray Furnaceman I always have to manually turn on my fireplace it has the thermopile system I use the igniter to turn on the pilot then I wait for the fireplace to light up sometimes it takes days and then it just keeps burning until I close the gas valve any thoughts of what I can do to correct this problem before calling in a repairman

Thank you

I have a thermopile on my gas boiler. Yesterday I had to hold the pilot button down for 10 minutes before the pilot would stay lit. Does that mean the thermopile is at the end of it's useful life?

Make one on induced furnaces

I'm about to change the thermopile on my gravity furnace. On the valve I'm not sure which post the red or white wires are supposed to go. Will it damage the thermopile if they are connected to the wrong post?

May I ask if a water heater thermocouple be the same piece to replace a stove thermocouple? Or does a stove require a different piece all together? Thanks in advance.

I was wondering if you could tell me a little about how the old large pizza oven temp controllers work. Its old and has no external electricity hooked up. Just a copper temp sensing probe attached by what looks like a copper capillary very similar in appearance to a thermocouple.

Why is a thermopile used? When you need higher voltage to open a bigger load? Why is a voltage output higher than that of a thermocouple needed? Is it to open bigger valve or something?

what I want to know is, what do you check for if the gas/pilot is lit, but wont go on when the switch is turned on, and knowing that there is power to the switch?

How long do thermocouples/thermopiles last in service?

I was told that my fireplace was done due to a bad valve and informed that, parts were not available 4k for a new fireplace replacement. I got a second opinion and the thermopile was faulty, got it changed and now the fireplace works fine...

wondering if you could give me a little help my fireplace keeps going out but the pilot light stays on

There will be more on the thermopile system. GFM

I'm able to light my pilot and it will stay on. However, when I turn the knob from Pilot to On, the pilot flame goes out immediately. Would yo suspect the thermopile or thermocoupler as the problem? Or, something else? Thanks

How long will that little propane torch run on a single canister?

Can I replace a thermocouple for a thermopile in the same gas log fireplace? Thanks

Hello sir. Could you help with one fireplace problem? Cdvr36nv fireplace. Direct-vent. It was shutting down on itself. I checked thermocouple, found that it is weak and everything rusted. I replaced the thermopile/pilot assembly. It was working, then I got a call from the customer. It is working but then again shuts down. I went started checking. Something weird was going on. Pilot was normal but after sometime it became lazy not touching thermocouple. And after sometime shuts down again. I tried to adjust pilot pressure, flame was not changing. Tried checking pilot pressure, no pressure. So I replaced the gas valve. Again the same issue. I am out of the options now 😂 Vent is clean. No idea what's wrong with it. I would think maybe air ports (although I dont know where they are located), but why pilot flame is not changing while adjusting it (on both gas valves) 🤔 Any help will be appreciated. Thanks

My new gas fireplace has both. Pilot in the middle with thermopile on one side and thermocouple on the other. The flame touches both. The fireplace goes out after a few minutes. Any idea what I should do to trouble shoot this issue?

The remote wall switch will not ignite the fireplace. The local switch next to the gas valve will ignite fireplace. What could be the issue. The mV on the terminal board seem to be in the good range when both switches connected. Any help is appreciated.

Really enjoyed your video and have some questions regarding a recent repair I performed on a Heat-n-Glo gas fireplace. I was having problems with the fireplace when I turned it off in the evening it would snuff out the pilot light. Relighting the pilot became progressively worse. This went on for several weeks so I decided to replace the pilot light assembly that contained a thermocouple, thermopile and Piezo. I replaced it today and achieved a nice blue flame on the pilot, however cant seem to keep it going for more than 8 minutes before I hear a click in the valve assembly cutting off the flame and the pilot light. The pilot will restart after a few minutes. I feel confident I made the repair correctly. Did I repair the wrong part, should I have replace the valve assembly instead? Your thoughts would be most appreciated. Thanks

Mine on my millivolt system is putting out about 700 millivolts and the tip of the thermopile is glowing red a little. Is the pilot set to high?

under what reading would be considered a bad reading for a thermopile. Is under 24 millivolts a circumstance for replacing a thermocouple.

We'll I tried new thermo couple still no luck only lights on the manual side of the switch the stove shop said it could be the gas valve but has been discontinued becouse the stove is 15 years old

Is the controller from a gas fryer?

IKe pilot on my gas fireplace will not stay on for more than 10 minutes then shuts off. What is it's problem?

Hello sir, do the gas oven thermostats contain Mercury? I have Eurosit 630

Will the pilot stay lit with a defective thermopile?

At 3:32 did you mean to say thermopile instead of thermocouple?

Well, you can put them on, but they won't work right! Thanks for the thoughts. GFM

can you tell me how many amps does that thermopile produces?

The Thermopile is an over temp cut out probe?

Why does my voltage go up then drop while testing a pile?

It's only hitting the front half ands it has a gray color to it thanks

how make thermopile in low prise please adviced me.

I've run into a problem with my boiler, I have only been living in the house one year, so last year I called a company and they charged me way too much and did very little. The guy told me one of my boilers out of three needed to be replaced at the tune of 10 grand. But I called another and that guy said a couple thousand and then another said a couple hundred. I wasn't sure what to do so I looked on line. I came up with the pressure was building because the pigtail copper tube was plugged up so I took it off and cleaned it out and it solved that problem. But the pilot would light but it would go out after the cycle finished. All the signs pointed to the pilot generator from what I could get people to say so I replaced it and yet the problem remained.From there I called a pro and he replaced the gas valve and then it would do the same as before. He then said I needed a new pressure switch and replaced that and yet it still did the same thing. But after a few weeks I did get it to function correctly but it would go out from time to time. What I did was adjust the setting on the pressure switch up and down one half turn at a time and that got me through the winter without too much trouble but annoying. But this year I'm not getting it to work and a guy from the gas service company who had come to change one of the meters, told me my thermopile needed replacing. So I replaced it and no it didn't do it. So I'm stuck, and I just don't trust any of these people here in the Boson area. Is there anything you can suggest that might solve my problem? I don't mind paying someone for their assistance but I'm not about to call someone else out to guess how much money I have in my wallet. I told one guy that I'll pay to get it fixed but not to replace what I've already replaced so he wasn't interested.

Be on the lookout for improper thermostats with millivolt systems ,, the compensator in a normal 24 volt "mechanical" thermostat creates resistance in the circuit , this thermostat might work with a brand new thermopile but as they weaken slightly with age you will end up with not enough current flow to open the gas valve .. the thermostat must be designed for millivolt ,, and not have a resistive compensator in the circuit,, had a gas fireplace that would work fine in the "on" position ,, but not work when in the Tstat position (not enough current due to thermostat being the wrong type) thermopile itself tested around 550 millivolts , replacing the thermopile with a new one would be a temp fix due to the new thermopile being slightly stronger when its brand new but the core fault was "thermostat wrong type"..

need to connect circulator pump to burner circuit,to operate simutanous. control ra832a not correct.need relay to connect circulator to 110 v circuit.

I have a gas fire place my stove will light manually when I flip the switch but won't light with the thermostat . pilot is working once stove manually starts and I flip the switch to thermostat it will run and shut off when it reaches set temp but will not restart when temp in house drops it's millivolt system if I disconnect the two wires put them together and start the stove flip it to thermostat will stay running separate the wires it shuts off any ideas would be great even tried new thermostat no luck thanks for your time

a thermopile is numerous thermocouples in one package

when t stat energizes burner

You need to be more specific. There are few induced appliances that use a thermopile. Let me know. GFM

Thanks. More coming on fireplaces. GFM

Power is in W not mV

SUPPER

Thermocouple

My land lord purchased a Whirlpool nautral gas hot water heater. This was a brand new water heater that was purchased from Lowes. The plumber hooked it up and it wouldn't fire. The thermal switch was broken. So since Thursday evening I have had no hot water. Isn't there a way to force light the water heater? Why doesn't the government force Honeywell to stop making those worthless electronic gas valves.

544 mil would reflect a woking valve. 250 to 300 mill would be a working valve with a load. What would be in mill volts a bad working valve

It is a millivolt thermostat battery power electronic I've changed wiring everything is tight and new battery's I'm baffled worked fine last year when I restated this year when the problem started changed thermal couple about three years old never changed thermal pile stove is about 15 years old Vermont castings radiance stove thanks for your time and writing back

I still don't know what the hell is going on or what a thermopile is… not helpful.