top of page

BENTRUP ERROR CODES - EXPLAINED

Has your kiln stopped mid‑firing? Are you seeing error codes on your Bentrup controller that you don’t recognise? Below is a clear run‑through of the most common error codes, what they mean, and the steps you can take to fix them safely.

​

If you need quick clarification, you can also Chat with Octo.

​

Ask Octo what a specific code means, or describe the firing scenario and symptoms — Octo can help you identify the cause and point you in the right direction.

Octo the Helpful Cobcraft kiln Firing Dragon

Thermocouple Fault Codes 

​​​

🔥 EA1 + our —  No Temperature Reading

  • The controller can’t read the thermocouple and assumes an extreme temperature.

  • Common causes: broken thermocouple, loose/dirty terminals, snapped or unplugged wire.

    • Fix: Check the thermocouple is plugged in firmly and not damaged.​

🔄 EA1 + udr — Temperature Reading Below 0°C

  • Usually caused by reversed polarity or the wrong thermocouple type.

  • Polarity reminder:

  • Red stripe on ceramic block = Positive (+)

  • Orange Bentrup cable = Positive (+)

    • Fix: Check thermocouple polarity and confirm the correct thermocouple type.​

​

⚡ EA1 + inu — Internal Cold‑Junction Fault

  • The controller’s internal temperature‑reading electronics have failed.

    • Fix: Contact Cobcraft — this requires controller repair or replacement.

​

Thermocouple faults are common and often the easiest Bentrup errors to fix. They usually come from simple issues like loose terminals, worn tips, or broken wires. The controller can’t read a proper temperature, so it throws a fault — which many users mistake for a major kiln failure.

If you’re unsure what your code means, you can Chat with Octo.

Give Octo the code or describe the firing scenario, and you’ll get quick guidance on whether it’s a simple connection issue or something that needs a technician.

Heating and firing performance codes appear when the controller detects that the kiln isn’t heating as expected. These faults usually relate to elements, relays, or power supply issues — but environmental conditions often play an even bigger role. Cold workshops, draughts, open roller doors, concrete floors, and winter firing can all slow heat‑gain enough to trigger performance faults. The controller simply reports that the kiln can’t reach the required temperature within a safe timeframe. Once you understand what each code represents, these faults are straightforward to diagnose and usually easy to correct.

Heating & Firing Performance Codes

🔥 EA3 — Over Temperature Shutdown

  • The kiln has gone more than 20°C over the programmed temperature.

    • Fix: Let the kiln cool. Email Cobcraft — this can indicate a stuck contactor.

​

🐢 EA4 — Heating Too Slowly

  • The kiln can’t keep up with the programmed ramp rate.

  • Example: Set to 100°C/hr, but heating at 99°C/hr or less.

  • Common causes:

    • 🎯 Thermocouple outside the kiln If the TC isn’t in the chamber, the controller sees no temperature rise.

    • 🌬️ Cold or draughty room Open sheds, roller doors, cold walls, missing fibre, enlarged vent holes — all slow heat gain.

    • 🧓 Aged elements Old elements have higher resistance and produce less power.

    • 🔥 Broken or burnt element wires Melted tails, loose or rusty terminals, shorted wiring.

    • ⚡ Missing phase (3‑phase kilns) A lost phase dramatically reduces power. Safe check: Look for a tripped breaker on your fuse box.

    • 🧲 Weak or failed contactor A burnt or stuck contactor reduces element power.

    • 🔄 Simmerstats not on HI (if fitted) If set too low, the kiln is de‑powered.

    • 🛑 Lid safety switch not engaging If the lid switch doesn’t click, the kiln assumes the lid is open and cuts all power.

​

Additional Heating & Firing Performance Codes
(TC95 & TC707 Only)

⚠️ EA5 — Temperature Loss Warning

  • The controller has detected that the kiln is losing temperature instead of gaining it.

  • EA5 is the early warning that something is slowing the kiln down — usually cold room conditions, heat‑loss, ageing elements, or reduced power.

    • Fix: Check the same causes listed under EA4 (slow heating), especially environmental conditions and element condition.

​

🔄 EA6 — Kiln Has Recovered / Ramp Rate Restored

  • EA6 means the kiln has caught back up to the programmed ramp rate and is heating normally again.

  • It’s not a fault — it simply confirms the kiln has recovered from the slowdown that triggered EA5.

    • Fix: None required. The kiln is firing correctly.

​

EA5 and EA6 show how your kiln is tracking against the programmed ramp rate.

EA5 appears when the kiln begins to lose temperature, usually from cold conditions or reduced heating performance.

EA6 appears when the kiln catches back up and returns to normal firing.

 

If the kiln cannot recover, the controller will eventually trigger EA4, shutting the kiln down as a safety measure — preventing severe damage that can occur if the thermocouple is left outside the kiln and the elements continue firing unchecked.

What You Can Try Before Emailing Cobcraft

Sometimes a kiln simply needs a little help to keep up with the programmed ramp rate. Before contacting Cobcraft, there are two quick adjustments you can try:

  • Lower the ramp rate by about 20 degrees 🧪 This gives the kiln more time to heat, especially useful in cold rooms or with ageing elements.

  • Use SKIP mode ⏩ SKIP tells the kiln to heat as fast as it can, ignoring the programmed ramp rate. How to access SKIP:

    • Go to the ramp rate

    • Increase to 999

    • Press UP once more

    • The display will show “SKIP”

SKIP is particularly helpful for kilns with older elements that still work but can’t meet strict ramp rates.

Email Cobcraft if:

  • You’ve checked the simple items mentioned above

  • You’ve tried lowering the ramp rate or SKIP

  • EA4 still appears

  • You suspect wiring, elements, or contactor issues

​

📧 Email keeps all support logged in our CRM system (Tradify).

EA8 & EA9 — Segment‑Progress Codes 

⏳ EA8 — Ramp Not Achieved

  • EA8 appears after an EA5 when the kiln still hasn’t caught up to the required temperature. The controller gives extra soak time to try to recover, but if the kiln still cannot reach the final temperature, the segment is allowed to continue anyway. (Bentrup: The system did not catch up with the temperature residue, but the program continued.)

    • Fix:

      • Check slow‑heating causes (EA4 list)

      • Lower ramp rate

      • Use SKIP mode

      • Improve environmental conditions (cold rooms trigger EA8 frequently)

⤴️ EA9 — Emergency Segment Exit

  • EA9 appears when the controller decides the kiln is no longer converging toward the final temperature. To avoid getting “stuck” in a segment forever, the controller forces the segment to finish and moves on. (Bentrup: Controller terminates the segment anyway — “Emergency Exit”.)

    • Fix:

      • Same checks as EA8

      • Confirm thermocouple placement

      • Check for heat‑loss (draughts, cold walls, missing fibre)

      • Inspect elements, wiring, and contactors if the issue repeats

EA8 and EA9 appear when the kiln struggles to reach the final temperature of a segment.

EA8 shows that the kiln could not catch up to the required temperature even after extra soak time, but the controller has allowed the program to continue.

EA9 appears when the controller decides the kiln is no longer converging toward the final temperature and ends the segment early as an “emergency exit” to prevent getting stuck. Both codes still allow firing to continue, but if the kiln fails for too long, the controller will trigger EA4 and shut the elements down for safety.

Power‑related codes appear when the controller detects an interruption or abnormal condition in the power feeding the kiln or the controller itself. These codes help protect the firing from unpredictable behaviour caused by short power cuts, long outages, or excessively high room temperatures.

Some power interruptions allow the firing to continue safely, while others require the kiln to stop and reset. Room‑temperature faults are rare but prevent the controller from overheating in hot studios or enclosed spaces.

Power‑Related Codes

🔌 E62 — Power Cut (Firing Continued)

  • Power returned quickly. The kiln resumes firing and continues the program normally.

    • Fix: None required.

​

🔌 E63 — Power Cut (Firing Stopped)

  • Power was out too long. The controller ends the program and resets to the end of the firing. You may need to restart the firing.

    • Fix: Check for unstable supply or repeated outages.

​

🌡️ E64 — Room Too Hot

  • The controller shut the kiln down because the studio temperature is too high. Improve airflow or ventilation — this is a very uncommon fault.

    • Fix: Increase ventilation, reduce ambient heat, avoid enclosed cabinets or tight spaces.

​

Internal Controller Codes

❌ EC… — Internal Controller Fault

  • Indicates an internal electronics issue within the controller.

    • Fix: Email Cobcraft.

​

❌ Ed… — Internal Controller Fault

  • Indicates a CPU, memory, or configuration problem inside the controller.

    • Fix: Email Cobcraft.

Internal controller codes indicate an issue inside the controller’s electronics, CPU, or configuration. These faults are not caused by elements, wiring, or power supply — they relate to the controller’s internal hardware or software. Because they affect the controller’s ability to operate safely, these codes require Cobcraft support to diagnose and resolve.

Additional Behaviour Notes

These behaviours are normal responses built into the controller to protect your kiln, your work, and the controller itself. After power cuts or slow‑heating conditions, the controller decides whether to continue, pause, or stop the firing based on temperature changes and safety limits. These actions help prevent damage to elements, bricks, fibre, and your pottery.

What Happens After a Power Cut

🔄 The kiln decides whether to continue or stop.

  • If power returns quickly, the kiln continues firing automatically.

  • If the kiln cools more than 50°C, the firing stops to protect your work.

  • If the kiln was already warm, the controller shortens the ramp time and restarts from the current temperature.

If the Kiln Cannot Keep Up With the Ramp

🟠 The kiln pauses and waits for temperature to catch up.

  • The kiln pauses

  • The Start/Stop light turns orange

  • It waits until the temperature catches up

  • Then continues the firing

  • If this happens often, the firing will still finish — it will just take longer than programmed

If all else fails, please email us at office@cobcraft.com or use the Contact button below.

We’re here to help with your kiln and controller advice.

bottom of page