7 Signs Your Kiln Element Needs to Be Replaced
Is your kiln struggling to hit the mark? You might unknowingly be working with worn-out kiln elements. Those glowing coils inside your kiln aren't just nice to look at: they're crucial for reliable firings and high-quality results. Ignoring element issues not only wastes time and electricity but can also lead to under-fired projects, glaze troubles, and frustrating kiln failures at the worst moments. Don’t let tired elements put your creativity on pause. Here are 7 clear signs it's time to swap those elements and keep your art flowing smoothly.
1. Prolonged Firing Times
Notice your kiln taking significantly longer than usual to finish a cycle? This slowdown often hints at worn elements. Aging elements build up resistance, limiting their efficiency. Imagine trying to fire an electric kiln with elements that are past their prime—it’s like sipping a thick milkshake through a tiny straw—things slow down considerably.
Longer firing cycles aren’t just annoying: they drain electricity and stress your kiln. If your firing times keep stretching, it’s a sign your elements need a closer look.
Why It Happens: Electrical Resistance Explained
Let’s break it down with a simple analogy: think of your kiln’s heating elements like metal water pipes, and electricity is the water flowing through them. These “pipes” are designed with just enough resistance to create heat as electricity pushes through—similar to how water rubbing against the inside of a pipe causes friction.
Over time, though, two things start to happen:
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Wear and Tear: With every firing, the extreme temperatures begin to degrade the element’s metal. This might involve oxidation, buildup, or microscopic structural changes. The inside of our “pipe” becomes rougher, which makes it harder for electricity to flow smoothly.
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Change in Shape: Elements can sag, warp, or thin out in places—like parts of a pipe narrowing. A thinner section increases resistance, forcing more effort (and heat) through a smaller space.
As electrical resistance increases:
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Current Flow Drops: More resistance means less current can flow at the same voltage. Think of trying to push water through a rough, narrow pipe—you won’t get as much out the other end.
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Heat Output Decreases: Because heat in an element is a product of both resistance and current, this drop in current means less heat overall. Your kiln takes longer to reach its target temperature—or may never reach it at all.
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Uneven Heating Develops: Some areas of the element degrade faster than others, creating “hot spots” or cold zones. This leads to inconsistent firing results.
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Potential for Failure: If one section becomes too thin or stressed, it may overheat and burn out completely, just like a pipe bursting from pressure.
In short, aging elements increase resistance and reduce your kiln’s ability to perform. That’s why longer firing times are more than just a delay—they’re a warning sign. If you notice your kiln dragging, it’s time to check the condition of your elements.
2. Not Reaching Target Temperatures
Aging elements lose their ability to generate adequate heat. If you're stuck at cone 5 but programmed for cone 6, your kiln is trying to tell you something.
When your kiln can't even reach the right temperature to open your kiln safely at the end of a proper cycle, it's a sign that your elements are struggling. Under-fired work means glazes won’t mature correctly, colors stay dull, and clay doesn’t vitrify properly. Protect your creative investments by replacing elements that can’t deliver consistent results.
3. Uneven Heating
Elements often degrade inconsistently, causing hotspots and cooler zones inside your kiln chamber.
These irregularities happen because aging elements heat unevenly, much like a stovetop burner that no longer warms uniformly across the surface. If previously reliable firing results suddenly vary, your elements might be nearing retirement.
How to Test for Hot and Cold Spots
Not sure if your kiln is heating evenly? These four simple methods can help you identify temperature inconsistencies and confirm whether your elements are to blame:
Witness Cone Placement
Set up witness cones on each shelf—ideally near the edges and in the center. After firing, check how each cone has slumped. If cones in different areas show different bending behaviors, your kiln is firing unevenly. This is one of the clearest visual ways to detect hot and cold zones.
The Biscuit Test
Load your kiln with identical bisque-fired test tiles or small clay slabs and fire them all in the same cycle. If some pieces appear over-fired while others are under-fired, it suggests inconsistent heating. This method gives you a hands-on view of how heat is distributed across your kiln shelves.
Glaze Flow Test
Use identical glazed test tiles—same clay body, same glaze, same application—and position them in various zones inside your kiln. Fire them normally and compare the results. Tiles that show more glaze flow were exposed to hotter areas. Less melt indicates cooler zones. This is especially useful if you're troubleshooting glaze inconsistency in your finished pieces.
Use a Digital Pyrometer
For a more technical approach, you can measure the actual temperatures inside the kiln at different stages of the firing process. A digital pyrometer with multiple thermocouples (or one moved between firings) can help identify temperature variations. This method adds a layer of precision and is ideal if you’re looking for data-backed confirmation of uneven heating.
These quick tests can save you a lot of guesswork. If you’re consistently seeing irregular results in the same zones, it's likely due to uneven element degradation. Replacing the elements will help bring your kiln back to balanced performance and protect the integrity of your work.
Important Considerations for All Methods
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Kiln Loading: The way you load your kiln can significantly impact temperature uniformity. Aim for consistent and open packing to allow for even heat circulation.
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Kiln Vents: If your kiln has a vent, make sure it's operating correctly. Proper ventilation affects airflow and temperature distribution. Downdraft vents, in particular, are often helpful for improving uniformity.
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Element Age and Condition: As discussed earlier, aging or damaged elements are one of the most common causes of hot and cold spots inside the kiln.
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Controller Accuracy: Remember that your kiln controller only reads the temperature at the thermocouple—it doesn't guarantee uniform heat throughout the entire chamber. Witness cones or PTCRs (Process Temperature Control Rings) provide a more accurate view of what your ware is actually experiencing.
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Repeat Testing: It's a good idea to test for hot and cold spots periodically, especially if you notice changes in your fired results or suspect element wear.
By using one or a combination of these methods, you can gain a better understanding of the temperature distribution within your kiln and take steps to mitigate any hot or cold spots you identify.
4. Visible Element Damage
When was your last kiln checkup? Damaged elements display clear signs: sagging coils, visible cracks, stretching, or brittleness. If you spot these issues, it's not just cosmetic—they represent real safety and performance risks.
Visually compromised elements struggle to heat evenly, putting extra strain on your kiln’s electrical system. Keep your kiln safe and effective by replacing damaged elements immediately.
Credit: Ceramic Arts Daily Forum
5. Increased Energy Consumption
Aging elements require more power and longer runtimes to maintain temperatures, like pressing harder on the gas pedal of an older car just to maintain speed.
This inefficiency quietly increases your operational costs. Checking your elements regularly can save you significant money in the long run.
6. Error Messages or Kiln Malfunctions
Modern digital controllers often detect kiln issues automatically. Seeing error codes like "FAIL," "Er1," or "TCO" on your controller screen? These warnings indicate potential element degradation.
Don’t ignore these alerts. Your kiln’s diagnostic system is signaling an underlying problem that, if ignored, can lead to bigger headaches. Review your kiln’s manual or reach out to technical support. Often, replacing aging elements solves these issues.
7. Frequent Tripping of Circuit Breakers
Deteriorating elements can cause uneven electrical loads, triggering your home's safety mechanisms. Elements on their last legs may draw power irregularly or create shorts, signaling your circuit breaker to shut down.
If your kiln consistently trips breakers, it's time for a professional inspection and element replacement. Protect your kiln and your workspace from potential electrical hazards by addressing this immediately.
Related: Kiln Troubleshooting Guide for Your Problems
Keep Your Kiln Firing Right
Before recognizing these signs, you might have endured frustratingly long firings, higher electricity bills, and disappointing artwork results, all while wondering why your kiln performance suddenly dropped off.
Now you're equipped to recognize the signs of failing elements clearly: extended firing cycles, temperature shortfalls, uneven heating, visible damage, rising energy bills, error alerts, and frequent breaker trips.
At Kiln Frog, we're artists ourselves. We understand the importance of reliable equipment. Keep your creative journey smooth by staying ahead of kiln maintenance.
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