Gas Furnace Smart Valve, Ignitor, and Flame Sensor Troubleshooting! 

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.

You always do a great job of explaining things. Great video.

nice setup and you made it easy to understand. Thank you.

Really great explanation on smart valve function thanks.

Thank you for this. Mine sometimes doesn't ignite. I wonder if the sensor and pilot just need a cleaning. I hadn't watched it misbehaving in action yet---only heard it from the other room, and it'll retry in 5 minutes just fine (so far...)

Nicely done! Still hate to walk up on a SV, but I would have had an easier time with it if this video would have been out years ago.

very very helpful!!!!!!!

Thanks man

The blue wire on my board was loose thanks to your video my furnace works again

Awesome video explaining how this setup works. I have the exact same system on my furnace. Just trying to figure out why sometimes it will not ignite and blows cold air.

Excellent videos. Thanx so much

Very cool thanks

Question I have a Honeywell SV9501M2528 if I put the IGNITION SYSTEM CONTROL SWITCH to the off position my hot surface ignitor lights up but of course pilot & burner do not light, the switch being off prevents that, But then when I switch it to on inductor fan kicks on but hot surface ignitor never starts glowing? Is my Smart valve bad or could it be something else? thanks..

Great video, thank you so much for your time and effort! This helped me troubleshoot and get my house heating again!

Smart valves are the stupidest fucking idea ever

What if you’re not getting any gas pressure from the pilot tube or main gas exit and the igniter just glows red and nothing happens? I have 24v going into the controls on black and blue.

I have that same set up in my heater and have problems. Not ignighting. Igniter is not even coming on. Cleaned the flame rod

Excellent video. Thanks for sharing with us. Thanks God we still have unselfish people sharing and giving their time so we can learn more and become more useful for our company and our customers. Thank u again Acservicetechchannel

Great video. My black wire had no voltage. I removed the new ignitor connecter and checked the gas valve and had voltage. The connecter on the black wire was not making contact with the gas valve.

Great Video! Thanks for sharing

Do you know if the newer valves are giving a lower fluctuating voltage on the flame sense post? ( Cycles from 20v goes up to 50v then keeps repeating same reading)

What if the hot surface ignitor is on all the time is that just the valve going bad

I watched a smart valve that was messed up, the igniter wasn't lighting, The guy took a screw driver & twisted something on the smart valve & the igniter came on. What did he do? & how the hell does it work like that? its something i didn't know about until recently.

great video, learned a lot. Sv9500h gas valve is not producing 180v for flame sensor, only producing 2.0v . Igniter comes on, pilot comes on but no main burner. Please advice what I can do. Can I get a replacement IC board. Or is there components on board has failed, how can I test it. Thanks for any help you can provide.

hi, i was working on a rooftop with the same smart valve. but when i measure the black wire (flame sensor) i was only getting around 50vac. The flame rod was very clean. Why is that you're getting around 180vac but mine was only around 50vac? thank you for all your help.

Thank u ,so correct me if I am wrong so if the ignitor resistance is ok and it glows and u have good gas pressure .the pilot black wire should have 110 volt and the valve should send gas to pilot and the flame rod recognizes the flame and open the main gas valve thank u again

what if everything checks out and valve clicks like it should to open.the igniter glows but there so no gas flowing through what would cause that

I’m only getting 24v out of one of the leads from the valve to the igniter. Any idea what that could be?

EXCELLENT EXCELLENT EXCELLENT explanation of a smart valve pilot ignition system. Just was I was looking for too. I like the fact that you took the time to disassemble the pilot assembly for us noobs. LOL. It's exactly what I needed to see and learn how/what to do, as my igniter assembly, of the same type as yours int he video, seems to be the issue with my furnace not firing up. I ordered the replacement part, changed it out myself, and I have heat again. Woohoo! Thank you for making this. A big help that saved me time and money.

Hey buddy , I have high voltage going to smart valve but no high voltage going to inducer motor to start it up , I jumpered all the safety limits and then jumpered out the inducer motor and it started , I ohmed out the ignitor had 4 ohms . So I diagnosed a bad smart valve , but ppl haven’t went ahead with repair yet , is there something I’m missing here on the proper diagnosis ? It has an 8 pin low voltage Honeywell type molex plug to it as well, thanks In advance , highly appreciate your videos !!! 🙂

Can you make a video on how to check ground. I don't exactly know what this means but I do know if you don't have ground your flame sensor won't work.

I have a system with the gas valve. The flame goes on and off every minute with the new flame sensor kit. Could it be a bad gas valve?

Could you do a comparison video for the different Honeywell smart valves and how to trouble shoot the different ones.

Well I got it to work but if it is bad I do not know how much longer it will hold up -- it is the older model SV9500M2682 and from what I can tell it is no longer being manufactured. I believe the replacement part for it now is model SV9501M2056 (also SV9501M2528). I assume you would recommend that I get a multimeter and test the voltages before making any determinations -- it just seems until I can do that the Smart Valve is the obvious problem if it is not a short with that clip.

Great Video, only regarding the reading of the flame sensor, shouldn't be 180 Mili volt instead of 181 volts? Thanks

Thank you for great video. I have Honeywell SV9541M2094. I am not getting 24v on ignitor blue wires. I seeing 24v on one of ( black sideone) blue wire to ground. What could be the issue? If I manually use lighter close to pilot gas, it fires up and furnace start working. Any help on this?

Shouldn't it be a milvolt and not microamp on flame sensor? I know these type of meters aren't capable of measuring microamp but will do milvolt.

Hi there. I have a Dayton heater that I am trying to diagnose. I’ve checked all the different voltage you mention, and the only deviation I have is in the flame rod - I get 24V AC, which I have read someplace is proper for my valve SV9500M-2562 (propane). The heater will light and turn on, it then turns off after about 15 seconds. It then turns back on, and shuts off after 10 seconds… then 5 seconds… then 4 seconds… keeps on decreasing. I’m thinking something is getting hot and shutting it off, and subsequent heat events take less time to heat it (whatever it is) up. What other sensors should I check?

@acservicetech Very good video and very informative to the HVAC techs out there. One more item I would add is when testing the Carbide igniter, Honeywell states, at room temperature, the igniter ohms should be no more than 10 ohms. Above that it's advisable to replace with new igniter. Keep up the good videos!

Can you do a video on how to convert standing pilot to spark ignition please

Cleaned up the flame sensor rod and the pilot assembly and I'm back in business, thank you for this great content!

My SV9601M4167 smart valve isn't igniting the pilot gas. I've got a new HSI as well as gas orifice and have verified that gas is present during ignition sequence. Input voltage to the valve is dropping from 26 to 20 during the sequence with a max of 19.5 at the HSI after about 10 seconds. Any suggestions are great appreciated as I'd rather not keep throwing money at guesses.

What about.Inducer fan motor

Great video. I hate these damn valves lol

My icp 80% works and runs for 5 minutes then flame goes turns off but blower and inducer stays on then quickly fires righ up then runs fine

Great videos! I have a Sterling tubular heater in my shop. The main burner will not stay lit. I've checked everything there is to check and have even replaced the smartvalve and flame sensor. I've bypassed the high limit thermostat and ventilation proving switch. I have 11 WC of propane pressure and the flame is strong. I've ran a ground wire from flame sensor to smartvalve. It puts out 113v to flame rod. It has steady 5.8 uA of dc current. When it first starts up the main burner will stay on for about 2 min. on next attempt it stays on for about 45 sec. , then 30 sec, 30 sec again and last attempt 15 sec. So each time it stays on for shorter time. It then flashes 6 times indicating issues with flame sense. The whole unit is grounded properly. It worked fine the first 2 winters but then started acting up. Since it's in my shop it has very little time on it, probably less than 100 hrs use. It's all clean as new. The flame sense grounds through the aluminum gas tube from smart valve body as shown in your video. Even though there was continuity of less than 1 ohm between valve and flame sensor I added a ground wire between valve and sensor. I can simulate signal loss by disconnecting flame sense wire while its running during that 2 min cycle and burners cut out within a couple seconds. Then it tries again when I reattach. Everything is tight and clean. From what I've read, the pilot flame is supposed to stay on even when the main burner starts. It seems odd in that if the main burner didnt ignite, the pilot flame will satisfy the flame sensor to keep main valve on therefore blasting the propane out without it being ignited.Seems like a potential for explosion. I would think the pilot flame should drop out when main burner turns on, then main burner would be making flame sensor happy for the duration. As an experiment, when main burner was on (flame ignited), I took pilot flame burner/flame sensor assy away from main burner area (kind of like what you have shown in video and it has a ground path) and it still had 3uA of current. So it stayed lit for about 2 min as before. The smartvalve is a 9540 model. The igniter/flame sensor is a Q3400A. When looking at the Honeywell document for measuring flame current. It says that for a SV9540 - if current is less than 0.8 uA then check for low gas pressure, flame rod contamination, poor current path, etc. If it's more than 0.8 uA then replace the SV9540. That doesn't make any sense. It doesn't give any range of what's good. So what it is saying is that it must be exactly 0.8 uA. Which seems really low. I keep wondering if it is a typo. Even in the document a footnote says flame rod should be capable of giving twice minimum threshold even under poor conditions. So twice is 1.6 uA and I'm getting 3 uA with just pilot flame and 5.8 with main burner. Also, watching the ammeter, it never flinches at all at the moment burner drops out which would indicate a brief drop in flame current if it did. Well sorry for such a long story here. Just hoping to give you as much info as I can. Any help would be appreciated. Thanks!

I don't know about Honeywell OEM, but I took apart a compatible SS24 SUPCO ignitor and discovered that they actually use a copper cuff thing that is brazed to the nitride. This is totally inferior and doomed to premature failure due to the combination of oxygen and thermal stress destroying the braze (the reason I took the damn Chinese piece of crap apart to start with to see what happened). Nickel alloys OR BETTER are supposed to be used for the connector with a suitable solder and flux.

Dude, I've been a service tech for 22 years & believe it or not I've NEVER had to service a Carrier smart valve set up, until today. I felt like such a dummy with the customer over my shoulder, so embarrassing. It was actually a Heil and their tech support is bullshit. You have to have your HVAC supplier call them on 3 way and my Heil Supplier are douche bags, they didn't have time and couldn't help me today. If I was able to watch your video earlier I would have been golden. I picked up a board, pilot assembly, and the gas valve. I was 99.99% sure it wasn't the assembly because I didn't have 24vac going to the igniter but I wasn't sure if it was the board or the valve. The schematic wasn't very good. It didn't show what each wire did, it was more or less a pictorial. I like using a ladder schematic when I'm not sure of the wiring. Anywho, I changed the board and finally the valve. I hate being a parts changer. Luckily, I was able to return the board. I am now a subscriber, great video.

Great 👍🥃🍺 Stay safe. Retired keyboard super tech. Wear your safety glasses.

Heymy smart valve makes a loud clunking noise water was leaking on it when roof was leaking is it possible it shorted out and if so how do I replace it thank you

Thank you again I actually have a sv9500m 2500 are these valves interchangeable

great channel. have learnt a lot! from the uk

great video as always, who makes that meter that you've been using?

If I have this system, can I light my furnace manually, till I can get the part

Your video had everything, even the parts links for component I found I needed to replace after testing my Honeywell SV9501

Gas boiler pilot intermittent control module trouble shooting

I Have This valve. Hot plate lights, pilot lights and stays on. But then main gas does not start to flow. Then the furnace starts to blow but obviously there is no hot air. Do I need a valve or a board? Yikes I can't figure it out. Already replaced Hot Plate / flame sensor, and nothing changed.

I replaced one of these today and now the pilot seems to have way too much pressure. I'm not sure if it had any similar issues prior to me working on it. Is there any kind of pilot orifice that goes in this anywhere? Something that may have fallen out and I didn't notice?

I just left a service call. I discovered the flame rod had come in contact with the metal shroud that is situated over the rod. the assembly had been tampered with. the shroud was slightly bent enough to touch the flame rod. flame would not make. all i had was the draft motor. after viewing this video, i have discovered a means to prove a good gas valve. and how to carefully inspect the entire circuit without going down a rabbit hole. great video. i won't forget the nightmare of a service call that this last one put me through.

Hi I converted mine to propane. Same smart valve as yours. I’m using it for a fire pit outside only problem I have is that at the psi flow from the tank to the valve the burner won’t ignite even though the igniter is glowing. But once I lower the psi to about 2-3 psi it turns on, what do you think is the problem? Thanks.

9 times of 10 it’s going to be a bad smart gas valve, which are pretty expensive to replace.

Pilot seems very low any thoughts ???

I have an hvac unit that I just replaced the control valve with an exact replacement, but now I notice that where the flames go into the heat exchanger there are some orange flames flickering between the burners. It's not blow back because It happens even before the main fan comes on. I have checked It with my pressure meter set It to 10 for lp gas, and checked It with my carbon monoxide meter and there Is no carbon monoxide coming from the vents Into the house and the carbon monoxide coming from the outside flue vent Is only 17ppm. I looked Into the heat exchanger and couldn't see any cracks. This Is a 4 ton outside unit made by york. It is working fine just concerned about the orange flames. The flames going Into the heat exchanger are blue just like they should be. Also new Inducer motor It Is working fine. New Filter.Do you have any suggestions?

So the bread ties finally stopped working. I was able to get the resistance reading on the hot igniter and it is 4.8 - 5.0 ohms. The pilot light will not ignite but I can no longer hear the click from the thermostat calling for heat. There was a series of clicks when it is working that I am no longer hearing so now I do not know if it is the thermostat (original since house was built in 1969) or the smart valve igniter module Honeywell SV9500M 2682 HQ1009093HW. What do you suggest?

Wow! Thanks for helping a Kiwi down this side of the world! So this was very handy!! My pool gas heater stopped working last week! Has the same valve. So I put a meter on it and managed to get 24v on the heat igniter wires which I figured was the case as it was glowing. I just couldn’t get the pilot to start. The black wire to the rod was weird! It was fluctuating between 18-45volts? So long story short, it turns out the gas jet at the pilot end was blocked! Cleaned it out and got a good pilot. But then next issue...main burners would start but go out every time after about 10-30secs! I thought it must be the varying voltage in the rod wire so ran a new earth wire from rod to valve switch in circuit, no change. Tried adjusting the rod and heat receptor arms in case they were out of alignment, no change. Ran earth wire from pilot to valve body, no change! Spent ages trying to figure it out. Turns out, I managed to fix the issue by dropping the pilot assembly down a little below the main burners. It seems to be getting too hot once main burners kicked off and maybe a safety was switching it off??? Any ideas??? As soon as a dropped it down, the main burners kept running! Seems to be working perfectly. Tried moving back up, burners went out!!! So, just thought I’d share this in case it helps someone else! No idea why it worked last week in that position and not anymore? Can only think when I took it out I must have bent the bracket or something causing it to lift too high? Hmmm??

I have the same valve on my Dayton unit heater it works intermittent how can I check it?

Great video, much thanks!! I've got a question. I'm having some trouble with the on/off switch. If the switch on the gas valve was in the off position, would the ignitor light???. I'm dealing with a possible broken switch and Im trying to confirm if it's on or off. Everything is working except no gas flow to pilot.

Thank you for a very helpful explanation video 👍

I appreciate your dedication but it would be way better to use a schematic diagram while dealing with the electrical part.

Dealing with old rtu out on the field… this will def. help! 👍

Hi, my hsi had about 4.8ohms. Both blue wires have 24vac. But the hsi is not glowing. Black and blue wires also have 24vac. Is it bad valve? Thanks

Quick question does the pilot stay lit 🔥 after main flame turns on?

Where does the orange wire go to off the smart valve? The board?

Great presentation.

What inch water column should you get at the pilot tube?

great video

Need help. Lol I have everything you are saying but no ignition on 24 volt hot surface igniter. Please help. My girl had no heat and I'm worried about the kids and the animals. Very good video

Great video to understand how the furnace works. Would be possible to have faulty Igniter/Sensor that works with thermostat without C wire and does not ignite when replacing with thermostat connected to C-wire? Also, I measure the resistance on cold HSI and it is 4.1 oms. Trying to troubleshoot the 19 years old furnace when newer thermostat connected through C-wire.

I do not have a meter but I believe my smart valve is bad. I was using a bread tie to pull on the igniter clip that locks into the smart valve because I found if I move that clip the pilot light would ignite. I had the bread tie pulling that clip in towards the pilot reset knob (it was wrapped around the igniter clip and the reset knob) so that the pilot light would ignite and stay lit. The problem was the pilot would not stay lit until there was a click after the induction motor would start. If I pressed that igniter clip that fits into the smart valve backwards I would hear the click and the pilot light will light and stay lit. I found if I let that locking clip go into the normal position the pilot light would shut off. Now after a couple of months the pilot light will not ignite no matter how much I move that locking clip. I did notice when I would move that locking clip that there was a small spark right where that clip fits into the smart valve just before the pilot light would ignite. Do you believe the problem is the smart valve or could there be a short where the locking clip fits into the smart valve?

My hot surface ignitor gets red hot what do u think it could be the pilot flame doesn't light ?? Thanks

pick it up and bring it back ?

Can you give a proper complete connection of it

Good. Video. It brings back memories of York gaspacks about 14 years old and some ducanes I've worked on.

A little bit confusing

What is the valve that you’re working on? I have a bad connection between the 3 pin connection and the igniter, everything tests good individually but when connected, the igniter doesn’t receive voltage. Thoughts?

Thank you very much, your explanation and shows are very useful tools.

Thanks again for video, I guess I was wrong it wasn't the board it was the smart valve. Lol

180 volts? You responded to Mike Kahidi but I can not decipher your answer. I thought it was millivolts as well. Please clarify.

My smart valve is only getting 9.5 volts for the flame rod, not 150 to 180 volts.Bad gas valve?Great videos!

I am having a Lennox furnace, was having issues where the main burner was not coming up so I decided to purchase a new smart valve...went with the SV9501. After doing the replacement now the pilot will go on and the main burner would go on, but when I shutdown the furnace via wall switch the pilot does not go on. I check the actual rot and igniter and noticed the blue wires by the hot surface igniter as well as the black wire of the flame sensor were a bit melted. I am trying to understand what controls the pilot gas output. I know it comes from the valve, just wondering if the frame rot and the hot surface igniter are the one controlling the sequence along with the Smart Valve. Before I go ahead and purchase a new hot surface igniter I would like to hear your recommendations. Thank you.

Great video.great channel. Thanks for your effort.

Great explanation and presentation!

hey great video..can you do the 2nd generation smart gas valve. thanks

Well done

Hi there,Great video - I replaced my smart valve and igniter about 6 months everything worked well until lastnight.So im troubleshooting now. I have 24v from pressure switch, 24v on hot coming into the valve.Question: for the 2 blue wires on the igniter - is there supposed to 24v coming from each blue wire...?Right now I only have 24v from one of the 2 blue igniter wires Your help would be greatly appreciated!!!!

RU-vid heroe

Infinitamente... Gracias.

Thanks for the videos they are very informative. But I do have a question. I just replaced the surface igniter in my sisters furnace, it had burned out. when I turned the power back on it fired up and ran fine, but never fired up again. I went back up and everything was working as it should the igniter heated up and i could hear the gas valve clicking open but not letting gas through. I tapped the gas valve a couple times and tried again and it fired off and ran fine so I turned off power and tested it 5-6 times and it worked as it should. I talked with her this morning and its not lighting again and ideas? Could it be a piece of trash sometimes blocking the gas jet at the surface igniter? ( I'm guessing I can't get that lucky )

Clean and explicit video, thanks

Why does the pilot stay on at all times on mine? And when I get a heat call the main gas does not come on but if I remove the surface ignitor/flame sensor prong the main gas opens and it starts heating