ErC 6864


Yeah 5000 is too low. It should be around 12000 to 16000


I’ve seen IBTS Fan Speed numbers that are variable since I received the unit. The speed varies between ~5,6xx & 16,1xx RPM. That sound possible? Iirc, as temps rise the speed rises with a max of about 16,1xx RPM when roasting, never less than 10,xxx while it’s hot. If the speed is supposed to be constant then the fan has a problem. I’ve assumed all this time fan speed was a controlled variable.

The fan was clean. Tiny amount of dust crumbs (like broken up chaff)… same stuff I see on the inside of the front plate. No sign of the white dust-like stuff (smoke) that John Rathwell had a photo of. Of course I’ve not roasted nearly as much coffee as he has so maybe it’s coming.

After I got it back together I powered up and immediately got the ErC 6864; disappeared almost immediately. Fan speed was as described above (variable). I recalled you mentioned the unlikely possibility there was an issue with f/w so I d/l’ed 538 again. After the ritual power-up/power-down x3, I went to PreHeat where I momentarily got the ErC about 4 times. Didn’t stick around long, but things are not like ‘usual’. I’d say the f/w d/l changed nothing.

Btw, re-assembling the Control Panel was an issue that could have been a lot easier with about 1" extra IBTS cable length for an old toot who learned long ago he’d never have the skills of a tech! :slight_smile:


Btw- I opened a Ticket about this via the Aillio site.


The new firmware will ignore the warning until after 20s to the fan has enough time to ramp up.
Interesting that it is a function of temp. I will help support try to solve these issues.


I’ll check for an update in a few days.

Is IBTS fan speed a controlled variable? or does it vary on its own?



I heard back from Matt Yao at Aillio support. Apparently fan speed should be relatively constant… there is no integrated speed control. IBTS Fan Speed has varied on my Bullet since it first arrived in Jan 2019. I have assumed (there’s that word that always gets me in trouble!) all this time that was normal. That’s not the case.

I contacted Sweet Maria’s and Julio has a fan on its way to me. Hopefully that will resolve my issues.



I’m still waiting for the IBTS fan to arrive (USPS said it was supposed to arrive yesterday but… ??).

In the interim I decided to update the f/w to whatever is supposed to have the 20 sec time delay. I found f/w 540 which, as it turns out, is what I already have… ?? I had updated last weekend on the chance I had a bad d/l; it said 538 when I hit Update but 540 is what installed. Odd. Never tried it so I missed my chance to not sound like an idiot!

Found a few issues that affect USB comm and RT operation…

  • Had to cycle power 3 times (waited 20 sec at power off), but eventually got RT to recognize the Bullet. Then I found a notice (center screen) said “Preheat your roaster…” and another (lower left) said “Roaster disconnected”. I had to cycle power again and also restart RT in order to get RT to recognize the Bullet was connected. I’ve never seen the Roaster Disconnected (lower left) before. In the past I only saw the Preheat… message if the roaster was connected. Something not right here with detecting comm. Seems related to start-up after f/w load. (Screenshots Connected & Disconnected)-

  • Went to Preheat and operation was also really odd. Typically I see IR Drum Temp head up smoothly to target (in this case 446°F) then settle very close to final value. Bean Temp increases to about 270°F. RoR goes as high as 30F° then decays. Not this time! Bean Temp was very slow to rise and RoR was all over the place. Bean Temp was flattening at about 90°F. I’ve never seen this before. Sorry… no screen shot and the chart didn’t save as I didn’t cycle into Roast & Cool. I assume this is an RT error but maybe it’s f/w… ??
  • When cooling after trying Preheat as the roster was finishing Shutdown, it started throwing ErC 6864 error codes repeatedly… perhaps every 1.5 to 2 sec. The 20 sec delay must not get applied properly at the end of the mode.
  • Still see the same issue with the exhaust fan not running during Preheat even when the roaster gets up to temp. Is this really what we want?! Suggests I could just shut off the roaster when it’s hot without letting it cool first which would make no sense.
  • Edit… Did one roast without incident. No ErC’s. Highest IR Fan Speed was over 17,xxx rpm. I’ve not seen a speed that high before. Net Voltage stayed above 112 VAC @ P8/118 VAC on Kill-A-Watt; 114 VAC @ P7/119 VAC on Kill-A-Watt.

I had no ErC 6864 codes generated, though the Control Panel was acting oddly and alarm sounds kept popping for the first several seconds when it went from Off to Preheat. During Preheat Info said IR Fan Speed was 4,1xx - 5,2xx rpm with occasional bursts to 10,xxx



Thanks for your details! Will look into it.
So low RPM at preheat, then higher at roasting and then at cooling it drops below 4000 to give the error.
BTW the delay for that error 6864 is only in the beginning after startup, to give the fan time to spin up.
Hope you get your fan soon!


Ah-hah! Right after start or late is when I see the ErC’s… so fits with what I’ve seen.



Received the fan from Sweet Maria’s (sent via USPS 3-Day Priority Mail and arrived days late). It was a quick 20-minute replacement done from the front… didn’t need to pull the front plate.

Since the part was so late arriving I decided try to roast a few batches before the replacement arrived. Couldn’t make it happen. The outside temps have dropped low enough that ErC 6864 is triggered immediately (my issue with the IBTS fan is temperature related). I couldn’t preheat the roaster as the power went to P0 immediately with the error. If I had been able to PreHeat it would have (probably) warmed the fan enough for it to operate at high speed, but outside temps kept that from happening.

Today was colder than yesterday but once the fan was installed I immediately tried set the Bullet to PreHeat. Started preheating immediately- no ErC 6864. I won’t be able to roast for a few days till the weather clears after Thanksgiving, but just being able to go to PreHeat suggests the issue is resolved.

Thank you Aillio and Sweet Maria’s!



Always good to hear a success story. Knock on wood…I have not had any troubles with my Bullet, but glad to see such superior support.


Oddly I’d had the issue since the Bullet arrived. Thought it was ‘normal’. Once the Bullet warmed up it seemed ok, but truthfully the lowest fan speed was getting slower & slower. If it ever warms up I can try a roast instead of speculating!



many thanks, Bruce
your suggestion help me !!


Just finished roasting with the new IBTS fan and all went well. Now that I see how it was supposed to operate I’m stunned it wasn’t a problem earlier. Wasn’t till the recent f/w change that it presented itself. The new fan operates ~16,1xx rpm with some small +/- variations.



Hi, there. I’ve been having some similar issues that I think are related to the IBTS fan. I’ve emailed support a bit, but wanted to chime in here too.

  • 11/24: Loud beeping when I power up roaster, screen not on so I couldn’t check erc
  • 11/24: Rebooted a few times, got to roast fine. Hear chirping/scratching noises coming from IBTS on startup, goes away during roasting when fan RPM is high
  • (went on vacation)
  • 12/2: Updated firmware and RoasTime, same issue but still able to roast after a few tries
  • 12/3 morning: Got Erc 6864 on startup, restarted a few times and was able to get the bullet running
  • 12/3 evening: Same Erc, able to roast after restarting a few times

How easy is it to access the fan to check it? I’ve taken the control panel front glass off, but am not sure what to do next.


It’s very easy to access but the lead lengths for 2 of the cables is very short. Take photos as you go so you can reattach anything that inadvertently comes adrift.

  • Remove the face plate (be careful of the cable for the speaker), then the
  • PC board (4 black screws); lift it to the side, then
  • 4 socket head screws that hold the control panel pedestal in place. To make it interesting there are 8 socket head screws to choose from. The ones you want are each on a small boss; the ones that are against a flat surface stay put.
  • At this point the pedestal is free but the 2 cables (plus the 2 blue wires) that pass thru the pedestal are really short; they lead to a single connector that attaches adjacent to the fan. It’s easy to detach unintentionally. The 2 blue wires are for the thermocouple and have no connector… be careful. Small cardboard boxes helped to support the weight of things that have cables still attached so the wires & connectors don’t get strained.
  • The IBTS fan should be visible now. There are 3 screws that hold it in place. Just remove these 3 screws and lift off the fan when you have the replacement. There is a tiny 3-wire cable that has to be disconnected from the connector board on the left. A pair of needle nose pliers helped.
  • If you did a good job documenting your way in, just follow the cookie crumbs back out and hope everything works once it’s closed up again. Check that all connectors are attached as you back out.

I won’t call it a piece of cake but it’s manageable if you take your time and document each step with photos. My new fan runs at 15,xxx - 16,2xx rpm continuously. The old fan would start at 4,xxx rpm and creep up a little as things heated up. Once I charged the drum fan speed went to 10,000 - 16,000 rpm and would drift around in that range. And the new fan is quiet by comparison to the old fan.



I did all of that, fan looked fine, put it back together and now it seems to work? I’ll see if the error pops up on the next few sessions.

Also, that speaker cable is a pain to get back in the right spot to get the cover back on. :joy:


What IBTS fan speeds do you have at startup and when hot? I was told if it’s under 5,000 rpm there’s a problem.



I am troubleshooting the same thing.
Been have some strange problems lately, was advised to upgrade firmware to 540, did that…now have ERC 6864. Opened up the system, cleaned the IBTS noticed a lot of debris on the fan, cleaned it all up, put everything back together. Same thing. ERC 6864.

We are down hard.


ErC 6864 was introduced into the f/w recently. It measures IBTS fan speed. Not sure the failure criteria but I think fan speed must be above 4,000 rpm. If it drops below you get the failure. From my experience it isn’t going away till you get a new fan.

The smoke particles are thought to be from the cooling tray. @johnrathwell had the same issue and I think @jacob has said they’ve seen IBTS fans returned with the same contamination. My failed fan was spotless but was still failing. ( Wonder if mine was clean cuz it wasn’t moving much air… ?? )



I wonder where all that debris come from.
Did you check If the fan does spin at all? You can check the RPM in RoasTime and you should be able to hear it spinning as well.
If it is completely dead then you could try soaking it in alcohol. Never tried this but worth a shot until you get a new one.