Gas stove burner flame low or uneven

A flame that is weaker than it used to be, or that burns tall on one side of the ring and barely at all on the other, is not just annoying. Rotis take longer, the cooker is slow to whistle and you burn more gas. The useful question is not “what is wrong with my stove” but “is it every burner, or only one?”. The answer points to different causes.

Every burner is low: look upstream

When all the burners are weak at the same time, the stove is usually fine. Gas is not arriving at full pressure, and the cause is somewhere between the cylinder or meter and the stove.

On an LPG cylinder

• The cylinder is nearly empty. The flame drops in the last few days of a cylinder, before it stops altogether. If it has been a while since the last refill, this is the first suspect.
• Winter. LPG has to turn from liquid into gas inside the cylinder, and it does that more slowly when the cylinder is cold. In a north Indian winter, a cylinder kept on an open balcony or against an outside wall gives a weaker flame in the early morning, especially when it is less than half full. Keep the cylinder indoors, upright and in a ventilated spot. Never warm it with a heater, hot water or a flame.
• The regulator is not fully on. Check the knob is at the on position, not halfway.
• The hose is kinked or crushed. Look behind the stove. A hose pinched between the platform and the wall, or squashed by a heavy pan stand, cuts the flow.

On piped gas (PNG)

• A valve is part-closed. Piped gas has a valve near the stove and another at the meter. A quarter-turn valve is fully open when its handle lines up with the pipe.
• The stove was never converted. Piped gas arrives at a lower pressure than cylinder gas, so a stove moved from LPG to PNG needs larger jets. A stove still on its LPG jets gives a small, lazy flame on every burner, permanently. The reverse is also true: a converted stove taken back to a cylinder burns too much gas with a tall, yellow flame. Either way, changing jets is a technician job.
• Supply work in your area. If neighbours have the same weak flame, call your gas company. It is not your stove.

Whatever the supply, do not try to fix a weak flame by fiddling with the regulator, changing it for an unapproved one or loosening joints. The regulator, the hose and every joint are part of the gas line, and anything beyond checking that knobs and valves are on is a technician’s work.

Only one burner is low or uneven: look at the burner

If the other burners are strong, the problem is at that one burner. The usual causes, roughly in the order we find them:

1. The cap is not seated. A burner cap sitting a millimetre high on one side starves that side of the ring. Lift it, wipe the rim and the base, and set it down so it sits flat and does not rock. Many caps only drop into place in one position.
2. The cap is on the wrong burner. Three and four burner stoves often have caps of different sizes. After a wash, a small cap ends up on a large burner and the flame is low and patchy. Match each cap to the burner it fits snugly.
3. Blocked ports. The small holes around the burner head fill with dried milk, rice water and oil. Where a hole is blocked, there is no flame. With the stove off and cold, brush the burner head with a dry, soft brush, and let it dry completely before refitting if you have washed it. Do not push a pin or wire into the holes: an enlarged hole changes the flame for good.
4. A draught across the stove. A cooler, a pedestal fan or an open window in summer can push the flame to one side of the ring. Turn the fan off for a minute and see if the ring evens out.
5. A partly blocked jet. If the cap and ports are clean and the burner is still weak, residue has reached the brass jet underneath, or the mixing tube between the jet and the burner. Both are inside the gas path and need the right tool.
6. A stiff or worn knob valve. If the flame does not rise when you turn the knob to high, or the knob is hard to turn, the valve behind it needs cleaning and greasing. That is part of a normal service.

For a short version of the one-burner checks, see uneven flame on one burner only.

When a weak flame is also the wrong colour

So check both halves of “lau kam hai ya peeli?”: the size and the colour. Low and blue is a supply or blockage problem. Low and yellow, or a flame that lifts off the burner and flutters, means the gas and air are not mixing properly. Stop using that burner until it has been checked. Our guide on orange flame on a gas stove explains what the colour is telling you.

Pan supports and the simmer that is not a fault

Two things look like a weak flame and are not. A pan support that has bent or is sitting crooked lifts the kadhai away from one side of the flame, so food cooks unevenly even though the flame is fine. Most glass-top stoves also have a small inner simmer burner on the big burner, and a flame on only the inner ring at low settings is the design, not a fault.

What a technician checks

• The supply first: regulator, hose, PNG valves and the date on the hose
• Each jet and mixing tube, cleared with the correct tool
• The jets matched to your gas, LPG or PNG
• The air setting on each burner, so the flame is blue and steady
• Knob valves cleaned and greased if they are stiff
• A soap-solution test on every joint at the end

If you have a Faber or Hindware gas stove, our pages on Faber gas stove repair and Hindware gas stove repair cover the faults we see on those models. We are an independent service, not the brand’s authorised centre.

If the safe checks have not fixed it, book a gas stove repair visit. A visiting charge applies, and you are told the cost of any part before it is fitted.