Troubleshoot the oil furnace part 3. Fire comes on but shuts down. 

10year old video and still helped me out today thank good someone somewhere posted a video cause I was screwed with a baby and no company to come out.

One small video for a man, one giant heap of knowledge for mankind. Can't thank you enough for what you're doing here with this series.

Thank you for posting this! You hit the nail right on the head. It is the middle of January and cold as a well diggers elbow here in Michigan. I have a workshop in the back half of my pole barn and the furnace had me pulling my hair (the little I have left) out. I have cans of expensive car paint and a bathroom out there that never want to freeze. But here I sit, in the house recovering from knee surgery. I showed my wife the video and she went out and did it! As simple as a dirty cad cell. And fixed for FREE!

Thanks for posting this video. It is very informative and well done. You don't spend too much time with trivial talk and you don't repeat yourself too much. Liked and subscribed...

This was fabulous advice! We've been replacing switches left and right, and the problem was the cad cell being dirty all along. Thank you so much! It's so nice to have heat again!

This is a great series of troubleshooting videos. Keep up the great work!

Thank you so much for your videos. CAD Cell was the culprit. Rather pay for a normal service call than an emergency call on a Saturday night...

GrayFurnaceMan Thank you so much for these videos. They are the very best step by step instructional videos for Oil Furnace that I have ever seen. Bless you for posting these on line.

Wow, thank you soooo much for this video, so well explained...Fixed my problem and we have heat and its so cold outside......Your the best..

Thanks so much for your video. Couldn't get anyone out here to look at my furnace. Decided to give it a whirl. It was the carbon build up, cleaned up the cad cell and BAM on it went. Running like a charm.

Your Videos Are GREAT !!! This Helped Me So Much, I had already changed the Filters, Nozzle, Transformer and Aligned The Guns. Furnace would not go past the 45 seconds.. Ohmed the Cad Cell, Cleaned It.. And BAM !!! I'm Back In Business !!! This winter has been HARD on Everything, but I know that my furnace has burnt about 1000 gals this season....It needed a Good Cleaning As Well !!!!!!!!!!!!! THANKS AGAIN.. KEEP IT UP !!!!!

Sir, you are a godsend! I recently purchased my family's abandoned farmhouse that has an old Milwaukee Thermoflo in it and was having this issue. I'm pretty handy, but had NO heating/cooling experience. This video just saved me hundreds of dollars and made me worlds more prepared. I cannot thank you enough, please keep up the good work and I'll be watching all of your videos!!!

Thank you for posting this! Cleaned it up and it worked again! God bless you and your family!

thank you so much for making these videos. I learned how to fix my furnace without calling repair man I was totally broke when it quit working. And thanks to you I fixed it. can't express enough how thankful I am.

Seems like every winter I refer back to your videos. Thank you!!!

Thank you ! I've been trying to troubleshoot why the furnace shuts down randomly and had ruled out the obvious, fuel and air problems. The next one I wanted to check was the CAD cell but I had no idea WHERE the darn thing was.. This laid it out perfectly and was able to inspect and clean it a bit.

Thanks Gray, your videos helped me get enough light to the CAD cell from the flame. I ended up needing to replace the nozzle to get a bigger flame. Ended up having to do it myself since the oil mafia did not want to work on my system here in new england very much.

You are the man!! Just got my boiler to work in 5 minutes. First oil boiler I've owned and it's old. No idea what I was doing. Thank you.

great vids gfm i fall back on these every so often

Thanks for the information and insight on what to do for trouble shooting a beckitt oil burner. Mine filled the house with black acrid smoke on Christmas day at noon. Thanks to you and your video tutorial I was able to properly clean, find the problem, which in this case was the cad unit..not easy to detect either..but like I said I was back in business and saved a boat load of money. Thanks again and God bless😎

I love watching your vida. has helped me out so much with my oil burner. just recently u helped out with my Cad cell. tested it as you described and it was actually bad. got a new one and boom, good as new and heat back on. thanks again.

Excellent pointers!!! I followed your step by step and found out the wire for the cad cell was damage. Fixed it myself . thank you

Hey man thanks so much for taking the time to film this for us, was having the same problem, but then did what you did in the video and she started right up. Really helped me out👍💪

My furnace would start and there was fire, then cut off. Remembered this video when I was researching another issue, and after cleaning the cad cell, happy family has heat! The windchill is suppose to be single digits tonight. Greatful for all your videos!

Many many thanks for your videos and taking the trouble to help me out. It is hugely appreciated.

My friend thank you so much for this lesson. New Years Eve and my furnace would not stay lit. After watching your video I was able to check my Cad Cell and connections and my old Burnham is staying lit. It's due to be replaced March so hopefully your videos will help me get by in a pinch before having to make an emergency service call. Cheers and Happy New Year!

You rock! I have been manually restarting my boiler every 10 minutes for the last 24 hours to keep the house warm and pipes from freezing. 12" of snow outside; no techs working today... Popped the cad cell out, cleaned it with a q-tip and rubbing alcohol... Runs like a champ. Thank you!!!

now I know what to tell my furnace guy when he comes to clean my furnace. I think I can do this my self!! good job

the World need more people like you!! thanks a lot my friend!!

Learned a lot by viewing your videos. Had a clue of what might be wrong with my oil furnace, before getting the repairman in.

Thank you for these videos, our furnace just stopped working in the middle of a polar vortex and the temperature was ridiculously low, we must've watched 30+ other videos that offered no useful advice until we stumbled upon this and I was actually able to fix it - somehow a burnt piece of plastic got in the igniter (no idea how that could have happened since it'd be running for months just fine) and was blocking the light to the cad cell - I never would have risked opening things up without knowing what I was doing, but I actually feel like I can deal with this kind of thing with very little stress now.

Thanks for sharing! You got me up and running again.

I lost you for for some time i was strolling through the heating channals and i saw furn.man and i said this must be the guy i have 18 years exp. Till i started waching ur vidios on u tube with all due respect u are the best u just about.cover evry little aspect of the furn.thank u very much

Very informative. Thanks so so much for your precious time showing us how to deal with basic things on the furnace and how to save some money annually on maintenance. Hey keep up the great work.Very simple way of detecting the problem step by step easy to follow the instructions. This is the way it should be on you tube videos not too much blah blah till we get to the point.

Found it. I changed out the ignition interrupter. Sweet. Thank you.

You are an excellent instructor. Thanks for these videos.

thank you, very well done. Good camera work, great explanation, & in only 8mins.

My neighbors furnace doing same thing; starts up and runs for minute then bam cuts off . I tested primary and new nozzle, and tested the igniter and all good so that's why I'm watching this video. Awesome information.

Thank you for the excellent instructions! Works like a charm😊

So first of all THANK YOU!.. I checked my sensor and it was actually clean (To Look At), I took it out anyway and cleaned. Reinstalled the sensor and hooked the Yellow Wires back up and Boom, she fired up and and kept running. Blew my mind. I have an Old Beckett Furnace it was reliable right until a month ago. I don't know if it was just loose or something but taking the Sensor out and giving it a clean (even though it didn't look like it needed a cleaning) it worked like a charm. Thank God for people like you sir, greatly appreciated. Gets cold here in Eastern Canada... Thanks! 🙏🇨🇦🤟

Hey GFM. I am a new subscriber. Your videos are really great. I had what I thought was a textbook case of a bad cad cell. After I replaced it, everything seemed to be ok, then tripped the relay. Didn't really make any sense because the flame was fast and correct. Turns out, the socket that the cad cell plugs into was worn and VERY loose. I replaced the cad cell assembly with a new socket and wires and now I'm good. I would guess that over the years, the cad cell was removed for cleaning many times and the tip was probably replaced but in the process, the socket was worn out. Thanks for sharing your knowledge.

Thanx for the knowledge. I checked the resistance and it was 1 - so a wire was probably cut. Traced the wire and it runs right above the impeller, in between the 2 igniter leads. The impeller had eaten through one wire and broke continuity.

Will do. It will be a few days before I get to it. I'll let you know what I find. Thank you.

Thank you for the awesome instructional video. I do have a question, I have the exact same furnace as the one in this video but I don't know the make and model. Someone painted over the information. Would it be possible for you to get the make and model of the furnace in the video. Thanks a bunch.

Hi there GFM… thank you very much for these videos. They are great! I have a Beckett 7505 Model AFG Series Oil Burner that is about 3 years old. In fact I had my entire furnace replaced then. I've been experiencing something similar to what you explained in this vid but not convinced it is it. I've just recently had the system cleaned and both the nozzle and filter strainer replaced. From reset (entire system off and then turned back on) the blower kicks on, the flame shortly thereafter. The flame then runs for approximately one minute and then goes into "recycling" with the green light flashing. After about 45 seconds the flame kicks back on and it goes through this cycle about 4 or 5 times before ultimately shutting down. Sometimes it is a soft lockout (blinking red light) and others it is a hard lockout (solid red light). I would imagine the serviceman would have checked the cad cell / relay during the cleaning but who knows. Any thoughts on how to get this thing to a point where I don't feel like the Old Man in The Christmas Story? It's a Cliiiiiinker!

Thank you so much. You have so much information to check out on your channel

Thank you!! My waste oil heater kept shutting off. I never knew what a cad cell was. Wish I would’ve saw this sooner.

Never even knew how to get to the nozzle Thank you issue solved great instructions \

You are giving away knowledge earned in a skilled trade.

Super helpful....mine was tripping and the sensor was a little cockeyed and a little dirty...fixed both and it's been great since. Thanks!

Helpful video well done and logically approached 👍

your video is very helpful this is happen to my burner same kind of symptom hopefully i can fix it...thank you for you video

Brilliant. Back to being warm. Thank you.

So my husband left me in the cold this morning with no heat on. I thought we ran out of oil, no we had 3/4 full tank. I said to him don't worry I will figure it out, thank GOD for your video. I can't wait to check the cad cell and relay all by myself! Your video is awesome that even I can follow along with it! Hope it's just as easy as your video. :)

Thanks for your tips! I ran through your checks and it ended up being a bad fuel pump shutting down. The fuel would pump then stop , and the fire would time out due to no fuel.

My burner was doing this. Cad cell was clean. Good oil flow. Everything good. I was about to bypass the cad cell and noticed its screw terminals on the controller were loose. Tightened them and burner is running. Whew, very relieved. I guess they got loose from the motor vibration.

Thank you saved a service call! Appreciate the effort!

FINALLY, someone who isn't selfish with the information and how to save money to fix something while learning at the same time. I checked my cad cell too and it was a little dirty. What cleaning product removed the carbon deposit ?, cause what I used did clean it up. I am extremely mechanically inclined so I really love this stuff

interesting/informative, thank you...

Great info really help me and saved me some money. Thank you so much

I know this video is old but thank you so much. I know nothing about furnaces but I was able to fix this with no trouble at all

Excellent video! Thank you!

thank you,saved me a lot of money

thanks for the vid....my burner started to shut off constantly lately .........was getting upset since we need hot water.....pulled out the flame sencer lens...cad cell....and cleaned it....it was not that dirty but had a light tint to it....put it back and she started up and did not shut off....hopefully that works for us thanks

Thank u so much, my cad cell was dirty and not point correct direction. Now I have heat back in my shop..

Thanks to your advice i was able to fix it by myself in a matter of minutes. Thank you so much!!

thank you !!!!!! my moms becky was shutting down it was the cad eye was dirty its 20 years old !!!! thank you your friend greg

I'm having an odd one here in Northern Ontario Canada. Kerr Oil Furnace, Beckett Burner, changed Intermittent Ignition Oil Primary (ICM1502) 30 sec timing.. Had guns sanded cleaned pointed, . 50 70'B nozzle replaced, CAD looked over (going to OHM test) and still intermittent operation. I can get heat at times then after a few cycles it'll trip. Reset and fail, reset works a bit then fail, reset then it'll work a full cycle. Replaced upstairs manual thermostat with a Nest 3rd Gen with the 2 wires connected respectively.

Thanks for posting, well done

Nice video, covered ok problem shooting, but do it yourselfers , a little knowledge can be dangerous, ran across enough of them as a service man, just couldn’t wait, even with a full free contract. One customer was even throwing matches into a furnace spraying oil, bad transformer. The furnace was in a closet, no basement, Oceanside, ny🤪

thanks a lot man my furnace is up and running the eye to detect wat u was saying some how it fell out and luck the fan didn't chew it up to bad I never new there was a eye there I put the eye back in and she is going good it fills good to have heat again

Thanks for your great videos. I have an old maybe 40 yr old oil furnace. Recently, its been short cycling. I replaced some things past service people did since its been a couple yrs of no service except air filters. I replaced Cad sensor and oil gun nossle. Electrodes seemed ok. Cleaned up gun with brake cleaner. Fired it up but keep going on and off quickly. Got got oil filter element but before messing with that, did your oil pump test. Took a hose to the oil pump output line going to the gun and started it to see if oil was flowing. I thought there was a blockage somewhere, but it flowed nicely. Connected things up and started the furnace, but still going on and off. I vaccumned best i could of chamber and flue before this. So I thought didn't get it all out. About to give up and call service person. Then I remembered something that happened 7 years ago that my furnace went off when it was 15° out on a Friday night and called the company I had a service contract with that was serviced that fall. The guy that came out check things and couldn't find it out what was wrong. Then, he shut the electric off from my main fuse box and checked the junction box connections going to the heater right next to it. He wound up not liking the wire and cut off an inch then capped and taped them. He started up the furnace and all was well. So that's what I tried. I shut the electric off like he did but I just Twisted the caps to make the connections tighter and any connections from the ignition box as well. To my surprise it started right up hopefully for good. Hallelujah! Is it common for wire to go bad? Thank you for what you do!

Totally helpful cleaned the sensor and it works fine

Thank you so much for your awesome video!!!! Helped me out TREMEDIOUSLY!!!

Hello my name is Rich.watched many of your videos & I thank you for sharing.I had a bad primary relay honeywell R4184d replacement is a R8184g which has a thermostat connection the orginal does not.I also have a Taco 4 zone controller the thermostat goes to the Aquastat what do I have to do with the tt connections on the R8184g will not work without something being hooked up. any help will be appreciated.

Hi, I just have a question. My furnace will stay on for a couple hours working fine, then it will turn off by itself and we have to reset it by pressing the reset button. It will then be fine for a couple hours. It turns off when it's really cold at night more frequently than during the day. Any suggestions would be great. Thanks.

Thank you for this video. If I disconnect the cad cell and put a wire across the relay terminals within a few seconds of ignition, everything works fine. While the furnace is running, the resistance across the cad cell (when disconnected) is infinite, instead of nearly zero. However, when I remove the top and flip the cover back, the room light shining into the cad cell is enough to make the resistance go very low, and shining a flashlight at the cell drives the resistance to zero, so it looks the cell is working ok. It is positioned correctly, and I don't think there's anything blocking it, and it is squeaky clean. When running, inside that part of the burner, there is a faint orange glow, not very bright at all. I'm wondering if there's some blockage or buildup that is preventing enough light from the flame from getting to the cad cell. Inside the furnace itself, the flame is blindingly bright as usual.

I want to say that your videos have me alot

I had a similar issue, the burner would sometimes flame out when first starting overnight. It would relight then work normally when recycling. Got to a point the flame caused a rumble then sputtered out. Having to reset almost every other day. I checked the cad, kind of looked like new, yet tested bad, 14 years old. Replaced with the original model Beckett. No more issues.

I've got an older Miller furnace in my garage with a Beckett AF burner, It will fire up (confirmed fire) run for the 45 seconds and trips the cad relay. I removed and tested the cad cell in the house and it seems to test fine close to 100ohms with good light. When I check it running I get about 12m ohms pre start and 7-8k ohms while it is running. Could the cad cell just be weak and not able to fully see the flame? Every now and then it will run like a champ. Thanks for the great videos.

great videos ...good job

Thak you. You've made things much clearer.

First off, thanks for these videos. Great information and an incredible resource for us DIY'ers who can handle certain things. Now, my question! I had an issue with my furnace just like your video above. I replaced the nozzle and electrodes, set them up properly, and reset the furnace. However the same thing happened. It ran for about a minute then kicked the reset. So, I took your advice and tried to clean the cad cell. After that, I tried it again and had the same issue. So I went to Home Depot and bought a NEW CAD CELL. Very simple to replace with your videos help. Now, the issue is a little different. The furnace will run for a day or two with out kicking the reset, then suddenly one cycle it will kick the reset. I will reset it and it will be good for a while longer (2 or 3 cycles, maybe a day or night) then I will have to reset it. There's no rhyme or reason to when it decides to kick. I'm just wondering if it is seeing the flame consistently or is there any adjusting of the nozzle or cad cell that could help this problem? Please Help?

Well I changed the nozzle it worked fine for a couple of times . It’s a shop furnace so I shut it down when I’m not working in the shop. Went to run it again and it would not fire . Pulled the gun cleaned it , thought maybe it was plugged . Still no go . Hit restart twice now I’ll leave it until I can get your directions thanks .

Thank you. In mentioning the fuel supply I recall the tech trying to clear the line as it was not so much flowing as it was dribbling out at open connector at burner. I think I'll see about cleaning the line for a good flow. Do you recommend suction or pressure or any solvents be introduced and flushed before reconnect?

So I bought a new home and it yas a grey wire not attached anywhere..it has like a metal piece on the bottom of the grey wire. The furnace will not even cut on. The green light did flash a couple times and it still doesn't work

Hey Gray! Thanks for all your videos. I've learned so much and I am determined to fix my burner myself thanks to you. = ) I am having (basically) the same problem as Orlando Rodriquez is having. Now I had my whole system tuned up in Oct 2014. New filter, the works. I bled my lines taking out the equivalent of 4 cups of oil. There were no air bubbles whatsoever and no particles. I checked my filters and they are nice and clean. This is driving me nuts! My furnace will run for the day, but then I drop the heat down at night to 64 and in the morning the house is freezing cause the furnace never kicked on. It has also been short cycling where it will come on for like 2 seconds and shut off. Then about 20 minutes later, it comes on and runs fine. I have cleaned the Cad sensor (it wasn't dirty to start with) and don't know if it's maybe the relay? My system is 10 years old. I have a Peerless boiler and a becket burner with a Honeywell R7184B cad relay. Do you think it's that Cad relay that needs to be replaced, something else or should I waive the white flag and call a tech? Thanks GFM in advance for your help and response back.

Thank you ... :) good stuff keep up a good work.

It just tripped again it ran fine for six hours.may have to pay for the emergency service .if i cant figure it out.i have no meter to test draft of fuel presser.thanks for the videos and any other info you have

Great video.

just got mine working thanks to your help. :)

Thank you for the enlightenment perfect fix!

This was great fixed me right up...thank you so much..dont have alot of money and this 1985 sucker going...you are the man

Thanks again for all your great videos! Very interested in your fuel oil videos! Work on lots of NG furnaces and over last several years gained much knowledge with boilers, but just never seen much experience with fuel oil other than changing them out. I don't see a change out much near in this future so looking to get some much needed attention to this ol beast until a change could be an option. I got a fuel oil furnace that looks nearly identical to the setup on this vid that was not lighting. Had call for heat, spark, fuel.. I found the combustion air intake vents alongside the pump were completely packed with dust/lint so cleaned that all out. I replaced the oil filter out at the fuel tank (wasn't horribly dirty but I know now it's clean). Checked fuel pressure on the original pump (2-pipe system). ... About 15-20ft of pipe and only a few feet of rise from tank to furnace.. But checking the pressure with a refrigerant gauge I only got 38 psi, and it would hold that after shut down. I tried to dial up the pressure yet didn't see any pressure increase. Anticipating this I had a replacement pump and installed that. Initial pressure check showed it factory set at about 98 psi. I made small adjustment up to 100 psi. I had also noticed the nozzle to be oversized. It had a .579 MH install prior however name plate spec .5 solid 80. So I replaced back to the .5 as manufacturer indicated. At this point I had forgotten to prime the pump, installed the gun tube, and proceeded to do a test to fire and held the door switch and it fired instantly and ran for several moments until I released the door switch. I then went back to properly prime the pump and yet again start unit in hopes to perform combustion analysis however the unit would not fire again. Bled more air from pump bleed.. still didn't seam to get a nice clear stream but bled probably a quart or 2 ... Unit still would not fire. Fan motor runs, great spark,.. I even tried moving the ignitor probes ahead a bit more thinking maybe the spray pattern and higher pressure were not allowing fuel to the spark but still no ignition. At this point I was thinking it's just not getting fuel at all. I didn't notice fuel mist in the box nor could I smell it. The gun tube was clear at time I hooked it back up along with the nozzle assembly. Im still waiting on my actual pressure test kit and smoke test kit to get in so at this point I called it a night as taking the gun tube and fitting off is a pain as you noted!!! Lol! And then plumbing in each piece of tubing to get to the pressure gauge! But thought I would recheck the pressure and if that checks back out good look back at the gun tube and nozzle. But thought I'd run my experience by you and see if I'm hitting all the bases or if you have any other tips or things to be aware of. Thanks again for all the time on such great teachings!!!!

OK I have a call for heat good spark and fuel oil coming in. My cad cell is not dirty, and the connections to the relay are good.So maybe the relay is bad? how can I check that?

I am trying to salvage a Lennox with an AFG burner. So far I have replaced the controller, motor, pump and cad cell. It still trips after 45 seconds. The best reading I can get with burner running is 168 ohms. If I shine a flash light into it the cell resistance drops to about 30 to 40 ohms. I suspect the flame is so smoky and jumping around that the cell cannot see a steady flame. I am taking my combustion analyzer with me today, which may answer my own questions. However I have only been in the business for a few years, and would like the opinion of a master. Enjoy your videos on RU-vid. Could you do a video about a smoky flame affecting the cad cell. Thanks

Nice tutorial!

you saved my day!!! great vid awesome info you rock!

Very good information indeed.

thank you so much you just saved me hundreds of dollars