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Fixing Commercial Ovens: Pilot Light Won’t Stay Lit

80% of the time the thermocouple causes this problem.  When lighting the pilot, if the thermocouple is not directly in the flame it doesn’t get hot enough to allow it to open the safety valve.  If it is directly in the flame and it won’t stay lit then the thermocouple is probably defective and needs to be replaced,  Keep in mind that some safety valves have the thermocouple permanently attached so the entire valve must be replaced. Commercial Oven Thermocouple

If you’ve replaced the thermocouple and attempt to light the pilot and it still will not stay lit then the safety valve is defective.  Remember to check the type of safety valve you have to get the correct replacement.  For correct identification  procedures check out this Tech Talk post.

When working on any type of gas equipment always remember to shut off the gas!

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About Greg McGuire

Greg has blogged about the food service industry for years and has been published in industry magazines, like Independent Restaurateur and industry blogs like Restaurant SmartBrief. He lives in Colorado with his wife and two sons and enjoys reading, live music, and the great outdoors.

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  1. Pilot light and burner go off at about 350 degrees replaced the pilot light and it was worse than the old one cut off about 300 degrees.
    Any ideas.

    • The above is a older wolf 36 inch commercial stove conventional oven

    • Hey Jerry,

      Without having more information, it’s tough to say what’s happening. The cutoff temp description sounds like a hi-limit thermostat issue. However, a pilot should never go out on its own (if it does, that could be a gas source issue). Give us a call 1-888-388-6372 or contact us online for more help.

      – Chris
      Tundra Team

  2. Hi Jerry,

    We have one of the older Wolf commercial range ovens. The pilot went from going out while the oven was in use and being difficult to relight, to now simply not relighting.

    The burners above the oven work just fine. Does it sound like a thermocouple issue?



    • Tundra Restaurant Supply

      Hi Brian,

      From your description, we’re thinking the thermocouple would be the most likely culprit.

      – Tundra Team

  3. I replaced the left thermocouple on my wolf 48 double. However, the left side oven still turns off, sometimes the pilot goes out too. The safety valve is almost new(just a couple years of use), so I am very confused as to what may be causing this. Thank you for your time! Trevor Barnhart

    • Tundra Restaurant Supply

      Hey Trevor,

      It could be a bad thermocouple, or the safety went out again. Give us a call at 888-388-6372 or contact us online if you want to troubleshoot further.

      – Tundra Team

  4. I have a Tristar not too sure how old it is but it is somewhat temperamental. The pilot light will stay lit sometimes for months and then we have days it doesn’t stay lit for longer than 10 minutes. Is this a thermocouple issue?

    Thank you in advance, Lisa

  5. installed the new thermal couple in my wolff oven, hard place to work on.especially the clip to secure it.

    Found 2 cracks iin 2 small tubes (messing or copper)in front of pilot light unit.

    can they be replaced or do I need complete new unit ?

  6. my pilet/burner knob won’t turn on my comb.gas valve on a tsf-6575 tri star fryer. is there a safety that’s keeping it from turning. it’s stuck in the pilot position

  7. I have a gas oven with a thermocouple, but it has 2 copper tubes coming out of it with electric connections on the ends, I cannot find any info on testing this type???

  8. Lenny, if you have a nice millivoltmeter you can hook it to that and measure the electric output. If it is a thermocouple, the output should be around 40 mV. If what you have is a thermopile, then the output should be more around 750mV.

    – Paul
    Tundra Team

  9. I have a Vulcan double oven with stove. Pilot light will stay lit and allow the oven the light up but then goes out. Sometimes it will be ok for an hr and sometimes it will go out in 5 min. Any suggestion

  10. i have a newer imperial oven with european style thermocouple, thermocouple extension, safety and oven thermostat are all in one i have replaced the thermocouple and extension at least 3 times a year and installed at least three thermostat/safeties in the last year and a half, is this a bad design ? I notice the newer imperial ovens went back to a conventional t stat and safety

    • Hi Mark,

      I would reach out to Imperial Directly. You can go on their website and lookup who their Vendor Representative is in your area, because they will be more willing to help you out, or contact the factory direct. If that doesn’t pan out the way you’d like, give us a call at 1-888-388-6372 and maybe we can get you into a heavier quality unit, because it’s possible that your demand doesn’t meet the quality of the unit you purchased.

      – Paul
      Tundra Team

  11. I have a gas Imperial Convection Oven and it sparks on and off and won’t stay lite. Once ightedid it will stay on. The problem when starting off and take away for it to finally catch

  12. I have a Bakers Pride Y600 pizza oven. The pilot will go out in the middle of a shift. We have replaced the thermopile and then the safety gas valve. Today I pulled the chimney out and cleaned the whole thing out along with everything I could reach inside the oven. I lit the pilot and started the oven. Within 45 minutes, it went out again. When lit, the flame is good and strong. Could the pressure regulator be bad? I’m not sure of what else we could change.
    Do you have anymore suggestions of something for us to try?

    • Hi Marcia,

      That has been a constant issue since they had to get away from the FMEA mercury switch valves and had to go back to those safeties with a thermocouple. One thing to check is the pilot tubing size. When they first made the change the kits were going out with 3/16” pilot tubes. Today, the kits come with a ¼” tube and pilot assembly. If your unit still have the smaller tube, that might be one thing to change that could provide some help. Also, keep spare thermocouples handy as the super hot burner compartment can burn them up.

      – Paul
      Tundra Team

  13. Hi Paul,
    My oven uses a combination valve R3104X and thermopile M1265X. Would the pilot tubing still be the issue? Everything I am reading talking about the tubing is referring to the other style of gas valve that uses a thermocouple and has a red button that you hold in to light the pilot. My gas valve has a white pilot knob.
    On the parts list, my parts specify (end 8/98 SN14164) but they were never discontinued like the other style.
    Thank you!

    • Hi Marcia,

      Well first thought would be just to replace the thermopile as they wear out. The company I worked for would replace them every 6 months for our customers, so that there was less of a chance of down time. That’s a hard problem to test. The thermopile is a power generating source for the solenoid inside the combo valve and it’s possible that the solenoid in the valve has gone bad, but you can’t tell without putting a new thermopile on and seeing how it runs. You could just replace both and be sure your problem is fixed. Hope that helps.

      – Tundra Team

  14. Hi Paul,
    I have a SunFire commercial propane range. 6 burners, 2 ovens and a griddle with broiler. Mysteriously last week one oven stopped working. My husband is a pretty handy fellow and we decided that it was probably thermocouple and the safety valve. So we bought 2 sets….one on Amazon (certified Garland Parts) and one set locally. We put in the set we bought locally and it’s as if the safety valve is blocked. We can smell the gas going in but for some reason it’s not going out. We’ve held the safety red button down and heated the thermocouple with a fire starter electronic match to no avail. It just will not light. Had a repair person out and he determined that valve was bad. So in the mean time the valve we ordered from Amazon arrived and we installed it and we are still having the same problem. It just will not light. It would be hard to believe that both valves are bad so something else must be going on….but we for the life of us cannot figure out what it is. Manuals for the stove are not very helpful. What else can we check. Garland SunFire Model # SX-6-24BG-2626. Baso Valve part # 1415703 Thermocouple Part # 4518817.

    • Hey there,

      One big thing to remember is every time you take apart the system you’ve now let all the lines fill with air. Gas is such low pressure it takes a very long time to blow all that out the very little pilot assembly. It’s not the best practice, but because I was impatient I would leave the pilot tube disconnected from the safety and let it free flow by pushing the red button until a noticeable amount of gas was flowing out. As long as your hood is on and moving air around in the kitchen, it’ll suck it right out of the air. Other then that, I’d find a new service tech.

      – Paul
      Tundra Team

  15. I’ve got a Comstock Castle Stove and cannot keep the pilot consistently lit. The pilot will go out in the middle of use or overnight when off. I have replaced the thermocouple, but the problem persists. Is the pilot valve defective?

    Thank you

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