Behmor max temps

[simonsk8r]

@artman I fiiiiiinally got around to doing your mod in my Behmor haha. Got my dad to drill the hole. Took some fiddling to make sure the probe doesn't keep hitting the vanes inside, and eventually just had to straighten the rod/wire inside instead of having the downward bend like in yours, but wow, it works great! Did some roasts today and it was incredibly accurate and consistent too, thanks so much for posting this and for all your help!!!

[artman]

Just a quick update spurred by some discussion on the "whats in my roaster" thread.

The bead probe is still going well, the insulation on the wire has melted in spots (small internal fire - some beans escaped the drum), and is showing signs of wear where it kinks around the door etc but still works fine. I have bought a spare to replace this one but no need, it is still going well.

Another tip is to make sure you secure the wire to the wiper rod along the side wall, to make sure it doesnt snag on the spinning drum.

And I have not taken the probe out of the drum lid, I just leave it in there, doesnt really get in the way of filling/emptying the drum.

Cheers

[artman]

No probs. I think the ET is done if you don't measure bean temp?

It's easy to do, you might need to re bend the wire to get it right so it doesn't clash with the vanes in the drum.

Also, I just leave the probe in the lid (yesterday was the first time I took it out to measure the hole diameter) and connected to the multi meter while I fill and empty beans.

Cheers

[AdrianWalton]

Hi Artman. You are probably right about not needing the ET temperature. I just noticed a few people who posted their roast graphs had a line for ET and I thought it would be interesting to track, but as you said probably not needed.

Thanks for your help on this. I think I have an idea in my head of what it all entails and I look forward to doing it.

Adrian

[artman]

Behmor max temps

Hi. Will have to check re hole size but you can not go too big as you need some metal left where it narrows for the spindle support. Also take into account eccentricity if you don't get it spot on. Mine was drilled by previous owner and isn't square, so the end of the probe moves up and down a bit as the drum rotates. Not really an issue.

I don't have an exhaust temp fitted, what additional info would this provide when roasting? I thought if you have bean temp you don't need ET?

Edit: hole diameter is 4.0mm, I chamfered the outside slightly with a larger bit. The stainless support strip is 2.5mm wide.

Cheers

[AdrianWalton]

Hi Artman,

A quick question on your approach for inserting a bean temp probe into your Bhemor, what size hole did you drill through your axle? Also, where are you placing your ET sensor and is it also a bead type thermocouple?

Thanks,
Adrian

Here are a couple of pics of my rough and ready temp people. I did this as a makeshift thing to try and do some diagnosis and it's been working a treat.

The probe is attached to the stainless piece (it's the bit in some windscreen wiper rubbers to make them stuff) with a bit of copper wire. The end bend allows insertion through a hole drilled in the left drum spigot and clears the mixing vanes.

The other bends make the end of the stainless "rod" sit on the base of the roaster so it doesn't spin around. The bead is situated at around the 7-8 o'clock position of the drum as viewed from the left end.

The "assembly " inserted into the drum- slid out from normal position.


In the drum in operating position.


Installed in the roaster.


Cheers

[artman]

I did notice that with my wiring sorted on the main board the temp didn't really get close to the temp cut out on manual P5 so it looks like this should not be an issue if the roaster is functioning correctly.

Cheers

[Andy]

...Going back to the max temp question, I measured the volts across the wall sensor when it cuts out at 166 degrees and got 0.581 volts.s

Close... the sensor will trigger Err2 when it reads 165C.... the 166C was "over-run". ;-)

FYI: when that sensor hits 180C you will most likely have bean ignition in the drum. We destruction tested one "to death" here a few years ago which was full of temperature probes and found that adding even 5C to the Err2 limit was flying too close to dangerous. Once bean ignition happens the temperature graph goes close to vertical and is uncontrollable at that point.

You don't need that much heat in the roaster to produce excellent roasts, if you are seeing Err2 you are probably ramping way too hot and are searing instead of roasting.

[artman]

Cool slow mo vid!

I just happened to replace the wipers on the car the day before and hadn't turfed the old ones when I came across the idea. Good tip re different widths of stainless. Having a screw/bracket or similar on the sidewall might be easier to stop the rotation of the rod, rather than the vertical leg resting on the floor of the roaster. I find mine sometimes snags between roaster and door, no biggie though. Phase 2 future mod.

A centre punch should help with getting the drill started in the right spot.

Going back to the max temp question, I measured the volts across the wall sensor when it cuts out at 166 degrees and got 0.581 volts.

Cheers

[moreCoffee]

Just the default manual controls, the stepped line is the manual power level (100 -> 75 -> 50) - Artisan can be a bit hard to read like that.
The other line is the exhaust temp, but I'll probably ditch that soon.

Good advice on the drilling. I must admit, even WITH a drill press I still managed to put the hole slightly off center and on an angle
I tried sooooo hard to get it centered, but there you go.... It isn't too bad.

Also to note, Trico have wiper refills in two sizes (6mm and 8mm), The 6mm has slightly narrower stainless rails - so I went for those to give me more clearance...

https://youtu.be/PsCRU8YQ1nY

[artman]

Is the stepped line the power level? Are you using a different control method? Looks like is it just under 90, as opposed to the built in 100, 75 modes of the Behmor? Or is the value on the graph just arbitrary?

One thing I have found with mine, is the the hole though the spindle is on a slight angle (drilled by previous owner), which causes the end of the probe to move around with each drum rotation. For small batches the probe comes in and out of the bean mass but only momentarily and it doesnt seem to affect the readout. So for people who are drilling their spindle, best done on a drill press so the hole is nice and square which will give you a steady probe.

Cheers

[moreCoffee]

Thanks for sharing your windscreen wiper mod artman - working an absolute treat on mine too

I've done a dozen or so roasts and every single one has returned a nice smooth bean temp and most importantly, it has been consistent roast to roast.
Another bonus is that it has no problem with small batch sizes - the roast below is 190g in manual mode, and the probe remains completely in the bean mass.

Cheers,
Pete

[artman]

Sorry Andy. I did have a quick look and didn't see it on bean bay. That's the one I am using, great price too. Will have to grab a spare on next order.

Cheers

[Andy]

Not sure to be honest re what probe it is. Might be the one that came with the victor DMM (I think it came with this and the stainless probe?) or it could be from one of my other DMMs. Either way you should be able to get something similar from Jaycar, Altronics, the bay etc.

...or from BeanBay!
CoffeeSnobs - BeanBay - Other Stuff - Spare Thermocouple Bead
(yes, it was originally shipped with the Victor and is in BeanBay as a spare part)

[artman]

Yeah for something that was meant to be a quick makeshift solution while I worked on mounting the probe through the the side (someone posted this version previously), it works very well. I just leave the probe in the lid so it's very easy. Not sure if with time the insulation will rub through (looking untouched at the moment) but I could always put a plastic (heat proof) bush in to protect it.

Not sure to be honest re what probe it is. Might be the one that came with the victor DMM (I think it came with this and the stainless probe?) or it could be from one of my other DMMs. Either way you should be able to get something similar from Jaycar, Altronics, the bay etc.

Cheers