HomeRoast Digest


Topic: iroast broken thermostat ? (13 msgs / 318 lines)
1) From: ~
Hi, 
I was wondering if anyone has had a similar problem and what is the
solution...short of a new one.
I have the hearthware i roast 2 that is now reaching 170 F at best....
It is beyond warranty of course, and they seemingly are ignoring my
emails.
The fan/blower is working well.  The 170 F temperature suggests the
heating element is fine.  I suspect the thermostat is shot.  So maybe
the solution is some simple by-pass of control circuit (for amateurs
here)  :) ...  to approach the good ol' poppers. 
Thanks!
daniel
-- 
The brain thinks, not man. Man is just a cerebral
      crystallization.
                -- Gilles Deleuze & Felix Guattari [1]

2) From: Aaron
daniel the thermostat should be simple enough to find in any electronics 
store.. its probably a thyristor or thermistor design...   I cant think 
of the exact name right now.
as far as bypassing it, err.  I think the thing is pretty much computer 
controlled and it'd be a bit more difficult than just jumpering the t 
stat as the temp controls the fan speed too I believe....
another problem might be if you do succeed in turning the heater on full 
bore you will roast your I roast in no time flat... too much heat there.
what you could try doing is putting some tin foil over half the vents on 
top to slow down airflow see if that does anything for you...
call them on the phone come monday morning and bitch about the crappy 
service, that's what Id do after waiting and no reply.....  either way a 
new base unit, which is probably what they will tell you you need is 
about 115 bucks or so im thinking last time I did an I roast 1.....  
personally I like the 1 a lot better,  much more control and less 
tempermental... but that's just my opinion.
Aaron

3) From: raymanowen
Thermostats don't break. I wish I had an iRoast so I could think it through
with you, but the overtemperature limit switch may be the actual culprit. I=
f
that's true, the 170 will be highly unstable.
If you can set the thermostat to a temperature below 170, say 150, tr=
y
that. If you can set a stable temperature below 170, that will eliminate
the thermostat and indict something else.
It's possible that such low temperatures are far enough below the normal
operating range that the thermostat wouldn't be stable anyway, but try it.
The temperature control may have worked its way loose, or may have lost
thermal conduction from the heater. Then you would set the temperature, the
thermostat wouldn't see any heat and keep the power applied. Next stop, the
over temp limit switch might trip out before you see the temperature on the
readout.
Has the machine been bumped before the temperature problems? The problem
sounds like a mechanical loose end, nothing actually broken. It should be
obvious if you open it up and look at the thermostat/ heat conduction path.
Cheers -RayO, aka Opa!
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Might=
y
Wichita (ex- NYC Paramount) WurliTzer- 1976

4) From: Larry Johnson
I have an iRoast2 doing about the same thing. Mine IS under warranty, but
"Frank" (the iRoast2 tech guy) and I are having trouble hooking up. We've
been leaving each other voice mail the past couple of days and now he's out
of the office until Wednesday. I'll let you know how it comes out, but it
may be a while.
Larry J
On 5/5/07, ~  wrote:
<Snip>
-- 
Larry J
Never give a party if you will be the most interesting person there.  -
Mickey Friedman

5) From: ~
Thanks all
for the comments....
I shall try a few things and will post back on any success ... 
daniel
On Sat, 2007-05-05 at 19:50 -0700, ~ wrote:
<Snip>
-- 
--------------------------------------
don't complain about the problem...
        be the problem.
        _the management_

6) From: Mike Koenig
Daniel,
Does your blower stay on it's high speed (the same as for the first
few minutes of the roast)?  One of my i-roast 1's had to go back
because the fan would not switch to the low speed.  It got hotter than
170, but I got nothing but baked roasts.  It might be something with
the controller circuit and not the thermostat.
If you want to hack it,  separate manual control of the heater and
blower would probably be a significant improvement.
--mike
On 5/5/07, ~  wrote:
<Snip>

7) From: ~
Hi mike,
Yeah, the fan speed is fine.
I shall start the "hacking" here on the weekend.
thanks
daniel
On Wed, 2007-05-09 at 10:32 -0400, Mike Koenig wrote:
<Snip>
-- 
--------------------------------------
don't complain about the problem...
        be the problem.
        _the management_

8) From: ~
Hi,
This is just to close out this thread.
So I tore the roaster completely apart, checking for blown resisters and
such.  All was good.
It was the obviously, though.  The heating element itself melted 
its ring-terminal.
The fix thus far ( well at least dozen roasts) was to replace the ring
terminal and simply bolt it through the original hole in the insulator
board to make connection with the wire on the other side.
I would recommend using a high melting point metal for the terminal if
possible to find.  I used some pretty soft metal...probably some
aluminum-alloy or ??? with a melting point near 1100 C ( Al melt)
probably...meaning the heating element is near 0.5 the melting point.
ONe should notexpect this to last too long.
Well it works, until I press send on this mail.
ciao
thanks! for the suggestions.
daniel
On Sat, 2007-05-05 at 19:50 -0700, ~ wrote:
<Snip>
-- 
--------------------------------------
don't complain about the problem...
        be the problem.
        _the management_

9) From: raymanowen
"a high melting point metal for the terminal if possible to find."
There are high temperature ring terminals. HVAC people use these all the
time to install and repair electric heating appliances.
I have many of these still in my tool box, and they look identical to the
standard terminals. That all changes when I try to crimp one to a wire-
they're made of nickel. I had a heavy crimper with compound leverage and
different jaws to handle them. Now I just use locking pliers [10WR
Vise-Grips].
Standard terminals are tinned copper and fasteners are zinc plated brass,
but even the nickel high temperature stuff will burn open if it gets loose
and arcs.
You can circumvent the ring terminals if you just double back the nichrome
wire for an inch or two and twist it. Then just bend the end into a "J" and
use that as the terminal. It will put you back in business with the roaster
until you can find the hardware you want.
Cheers -RayO, aka Opa!
Got Grinder?

10) From: Brian Kamnetz
Ray, I'll say it again, I sure envy you (and several others on the list) for
all the really interesting and useful things you know.
Brian
On 6/15/07, raymanowen  wrote:
<Snip>

11) From: raymanowen
I've spent many years working with heating controls and automation-
everything But coffee. The closest I came was roasting some Kenya AA about
30years ago in my fork truck battery charger shop. Others went crazy and I
always had to brew all 3 pots on my restaurant brewer.
But I still had no clue about the tantalizing flavor I was getting or how
so.
I get a kick out of the misrepresented toy trickle chargers on eBay. Just
like the toy coffee grinders can wreck coffee beans, the toy chargers can
wreck the 2 ton batteries.
Save a dime on the grinder/ charger, wreck $100s in beans/ $Big for a
battery.
Cheers -RayO, aka Opa!
Station wagons are now Crossover SUV's, *$ is still...

12) From: Aaron
Oh you hit that nail right on the head.  you try to explain to folks,  
Look, you just spent $150, or in the case of a forktruck  $1500 on a 
battery, don't be a dumb ass and get a regulated charger.  they think, 
well it's a 400 Ah battery, pumping an amp or two through it continually 
won't hurt it.... WRONG.  Two months later they bring in this bloated 
mass of melted casing and warped plates and scream that you sold them a 
defective item.  You ask them what they charged it with and they say Oh 
a wall charger, it's a little square you plug in the wall i got from e 
bay for 6.99.   He swore to me it wouldn't hurt the batteries.
Especially now that AGM's and sealed gells are becoming more common.  
Unlike a flooded cell where you can just add water and kind of make up 
for a goof unless you really cooked it, these, once you cook it, that's 
it, game over.
Say... we should get together and invent up a battery operated bean 
grinder for on the road.  Put a little lead acid pack or a NiMh in it,  
it won't have to do a ton at a time, maybe a 20 gram hopper, and go real 
slow with the burrs,  kind of like a roided out pencil sharpener.  
Little DC motors are cheap and easy to find, and you gear it right, 
it'll have plenty of torque to crunch through the beans.  Maybe a two 
stage, one set is a set of blades on top running axially to basically 
crunch the whole bean down into pieces, kind of like the setup alchemest 
john uses in his cocoa bean dehusker and drop the pieces down into the 
conical burrs where it then grinds them to the proper size. 
I bet we could do this.
Aaron

13) From: raymanowen
We think alike, Aaron. I never thought of the planetary burrs mounted like
the pencil sharpener blades for the stage I grinding. I was going to make
the whole thing in a conical roll mill driven by a 14 or 28v starter motor.
Unfortunately, the starter motor's bearings are just phosphor-bronze
sleeves, with no provision for axial thrust reaction that the second stage
cones would generate. In fact, all of my designs had relied on bearing
precision for the consistency of the coffee grounds size.
Why reinvent the wheel? When I found out I could get one of the brutish
Mazzers for the same order of investment I already had in the SolisMP, my
eternal search for decent Solis Burrs ended.
Sadly, I helped unload and store in my shop a 4 group espresso machine
upholstered in red naugahyde with black embroidered designs. I remember it
was a gaudy thing with polished brass and chrome levers. It looked like it
came from a Tijuana Cat House.
"You want it, Ray? It's part of an auction lot of electric welders and
machine tools, and you're the coffee expert." I'd only heard of espresso
drinks and really knew nothing about roasting, let alone the art of espresso
brewing...
Cheers -RayO, aka Opa!
A 2.5 ton 48v Ultra Deep Cycle L-A battery for $1500? Where?


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