Cooktop Burner Won’t Autolight

Having trouble with a burner that’s very slow to light or not lighting without a match? The gas and air flow/pressure must be properly balanced for everything to work. Pressure too high or low can cause problems. I learned I had to consider:

  • gas flow amount/pressure controlled by the burner head orifice
  • gas flow amount/pressure controlled by simmer orifice
  • air flow amount controlled by the venturi (air shutters)
  • air/gas flow through the flash tubes
  • flash tube between pilot and burner tube (could be clogged or not placed properly).

With the proper tools (wrench, screw driver) and a gas leak detector (my nose isn’t good enough) and a little patience, I learned I could adjust the settings, etc. to restore proper function. It required repeated attempts at adjusting (up/down) air and gas flows (one at a time), then turning burner on, turning off, then waiting 3-5 minutes for the flammable air in the tubes to dissipate.

Seek a professional gas stove technician if you’re not prepared to do this.

flowRegulators

The venturis <> air shutters <> butterfly vents <> wings. I’ve probably missed a few more nicknames for these things. While the burner valves allow you to control the gas flow, the venturi panels control the flow of fresh air. On these vintage stoves, since they look like basic butterfly wings, they have acquired other names.

With the exception of rust, they’re fairly indestructible. Extensive rust will cause pitting. I neutralized the rusting by soaking the panels and screws in phosphoric acid. After rinsing and drying, they were sanded with the rubber bonded abrasive wheels. I finished them with a light schmear of brake grease.

burnerFlames

When clean, lubed and properly adjusted, it’s especially nice to see the happy blue flames. What did I do? Wouldn’t you like to know. 🙂

First, I needed to make sure the gas flow through the burner control valve was not blocked by dirt, valve grease or debris, so I thoroughly cleaned the valve.

Second, the back of the valve has adjustable openings to allow tiny amounts of fuel gas to flow through. Being able to adjust these was critical. With a wrench, I could turn the orifice nuts CW and CCW to increase/decrease the gas flow.

Third, the flash tubes needed to be placed properly.  Some of flash tubes in my stove were held in place by cotter pins. Some were not. The pins aren’t critical unless the stove itself moves a lot and enough to disturb the tube placements.

With my stove, I had to lift the cooktop, remove the crumb trays and all the knobs so I could remove the control panel and the horizontal L-bar. This allowed me the easiest access to the orifices.

Now, the procedure is not the easiest to explain. I needed to use most of my senses and all my patience making micro adjustments up and down to the amount of gas and air, then turn the burner on to see if it would auto-light. If after 10-20 seconds the burner didn’t light, I’d manually light it, just to make sure the burner still worked. Then turn the burner off, wait until the flammable gas dissipated before trying again.

If I didn’t wait long enough, when I turned the burner on again, it would auto-light. It could do that because there was still enough flammable gas lingering.

Once I got the burner to auto-light every time, I learned not to touch the settings again. The adjustments stayed pretty stable.

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