[Homeroast] Behmor Fire

Martin Maney maney at two14.net
Sat Apr 14 10:49:52 CDT 2012

On Thu, Apr 12, 2012 at 11:24:27AM -0700, John Nanci wrote:
> chamber is cooler, so it keeps the elements on more.  Conversely, in
> hot whether, heat is not dissipated as fast from the thermistor, so
> they system interprets this as the chamber being hotter, so it
> cycles it more to keep it 'in spec'.
> Clearer?

Just as a confirmation of what I've observed recently.  Unfortunately,
I found the thermostatting entirely beneficial for the first four
months, when the ambient was around 60°F.  Since it's warmed up
outside, the room has been nearer 70°F, and I find that the
thermostatting starts sooner and is probably hitting a slightly lower
duty cycle, with the result that where I used to reach the doorway of
second crack with time left, I'm now at least sometimes running out of
time before I hear a single snap of second (though the cycling does
help stretch things out, which is why I used to like it just fine, so
there are a smattering of late pops of first, and it's not always clear
which category an isolated noise belongs to).

> I will also note that the newer models with the additional cooling
> fan on the side panel are much less prone to this as they are
> keeping the air in the side chamber exchanged more, so you see less
> variances with weather.

It's not enough, clearly, since this is one of those later production
articles.  I have had some passing thoughts about opening up the
perforations in the cover more to give that fan a freer draw... or
maybe even cut it open and mount a guard with a cleanable filter to get
both a freer draw and less dust sucked into the machine.  But now I'm
wondering if it might be more to the point to add a bit of series
resistance to the sensor to compensate for the ambient - get back to
the operating conditions that I found so conducive to happy roasting.

My main concern is that once I start modding the thing I doubt it will
stop until it's gotten a whole new brain.  The more you do, the more
you want to do more...

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