September 24 2017 06:57:01


Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
bullet2.gif Active Forums
bullet2.gif FORUM INDEX
bullet2.gif Downloads
bullet2.gif News
bullet2.gif Forum FAQ
bullet2.gif Contact Me
bullet2.gif Photo Gallery
bullet2.gif Search
bullet2.gif User's Voice
Forum Threads
Newest Threads
bullet2.gif Bread Maker roast si...
bullet2.gif TC4C Website Update?
bullet2.gif Baby George Foreman ...
bullet2.gif Vacuum appropriate f...
bullet2.gif Oreck XL blower and ...
Hottest Threads
bullet2.gif Building a drum r... [146]
bullet2.gif Bobby M15's drum [76]
bullet2.gif Baby George Forem... [53]
bullet2.gif 500g (hopefully) ... [34]
bullet2.gif Big Price Drop on... [29]
Donate to HRO
Please enter your site username (if you have one) and your email address (required) to be sent with this donation for tracking and contact purposes.

Site Username
If you don't have a site username, just enter "Guest"

eMail Address **REQUIRED**

Users Online
bullet2.gif Guests Online: 3

bullet2.gif Members Online: 0

bullet2.gif Total Members: 5,033
bullet2.gif Newest Member: mraphael
BotSlap Panel
bullet2.gif Last check: 09/24/2017 06:49
bullet2.gif Slap count: 0
bullet2.gif Last checked ID: 6141
View Thread
Who is here? 1 guest(s)
 Print Thread
Adding thermo probes to SR500
I've added on thermoprobe to the SR500. this is an 8" long rigid probe that I installed through the top by drilling a hole. The probe has a collar on it so I can set the location of the tip. Right now I have it about 1/2" above the bottom of the roasting chamber. It's probably as close to a bean temp as i'm going to get.

Now I want to add an environment temp probe. I'm thinking about drilling through the side of the base unit, through the heat shield and putting the probe just below the roasting chamber in about the middle of the plenum. downside is if I roast without a probe I have a big hole in the heat shield which I'd have to find a way to plug (False probe most likely)

Another option would be to drill another hole in the top and set the probe so it stays up towards the top of the chamber. This is just measuring the air temps after it's been passed through the beans. It's a bit easier to do, but Im not sure the information is useful.

pics might help...
I can try: Pics are (or should be) the existing bean temp probe. and 2 options for location of the environment temp.
Johnh attached the following images:
thermoprobe_opt_b.jpg thermoprobe_opt_a.jpg thermoprobe_bean_temp_probe.jpg
In the above pics. The left most pic is one option for an ET probe. this is easy - drill a second hole through the lid and mount the probe so that it stays high, up out of the bean mass. But, it is reading air temps after it's passed through the beans. I'm not sure what that information is useful for.

The middle picture is looking down on the base. I've positioned the probe I have about where I could mount another probe. It would go through the wall of the base and be in the hot air plenum directly below the glass roasting chamber.

The right picture is my unit as it is now with the long probe inserted through the lid. You can see the probe extends to between the metal bands on the glass roasting chamber. This is what I monitor for bean temps.
Not sure what the usefulness of exhaust temp would be... the input temp is more important, imo.
I mean a hole at the base, with probe near the perforated plate.
DIY: TurboOven with drum, Popcorn
Moded commercial: Dieckmann RoestMeister, Nesco
PID/ramp/soak controllers
Grinder: mod'ed Porlex to 47 conical burrs
Thats what I was thinking as well.

It's still a manual roasting process. The new probe shipped a couple of days ago, This may be this weekends project.
I don't think you need an ET probe in an air roaster, mine didn't. And your BT probe looks dead centered... I think you'll find that the bean temp it records will be on the 'cooler' side. As you go closer to the circumference, the temp goes up. I picked a location about halfway out, as I recall.
It's just the angle of the photo. It's roughly halfway from center to edge of chamber. The First photo is where that probe is. I just backed it out to show how I could place a downstream ET.
In this design, BT probe should be in the center of vortex, to minimize the air influence and measure beans as much as possible.
If there is any vortex, as in a popper...
DIY: TurboOven with drum, Popcorn
Moded commercial: Dieckmann RoestMeister, Nesco
PID/ramp/soak controllers
Grinder: mod'ed Porlex to 47 conical burrs
It occurs to me that drilling a hole in the chamber wall may be unnecessary.

I'm wondering now about using a surface mounted thermocouple on the exterior of the shroud. this would be relatively easy - though I'm not sure exactly what max temperature of the shroud would be. Most thigh temperature tapes I can find are rated at a max temp of 500F. I think that would be adequate.

Looking at the teardown page on the SR500 it looks as though the temp of the shroud is part of the temp monitoring of the machine itself.
270C seems a reasonable absolute maximum for the hot air to hit beans.
Many consider an even low value, at 250C (480F).
DIY: TurboOven with drum, Popcorn
Moded commercial: Dieckmann RoestMeister, Nesco
PID/ramp/soak controllers
Grinder: mod'ed Porlex to 47 conical burrs
This might be worth a try. They did not publish a clear picture of what I'm considering. But if the metal chamber wall I can see through the vents is really the chamber wall (i.e. not a double wall ) I should be able to place a thermocouple on the outside face of the shroud. Not as good as actual air temp - time lag of the wall, plus deficiencies in measuring surface temps, But perhaps a place to start. I may disassemble the base and inspect the construction. I have a couple thermocouples that came with the Amprobe TMD56 - I just need to find some of the tape to secure the thermocouple to the chamber wall.
You might consider extracting the wires and junction from the thermocouple enclosure, which make it too bulky for this job.
The active part of a thermocouple is really small, can fit in a 2 mm diameter hole, making possible placement in the hot air vents.
DIY: TurboOven with drum, Popcorn
Moded commercial: Dieckmann RoestMeister, Nesco
PID/ramp/soak controllers
Grinder: mod'ed Porlex to 47 conical burrs
Jump to Forum:
Similar Threads
Thread Forum Replies Last Post
SR300 vs SR340 vs SR500 Fresh Roast 8 and NEW SR 500 5 07/01/2017 19:55
SR500 How long to wait between roasts? Fresh Roast 8 and NEW SR 500 3 05/29/2016 11:59
Thermocouple on SR500 issues Fresh Roast 8 and NEW SR 500 12 04/15/2016 16:32
TC4C+HTC & TC Probes. My Hottop Install. HotTop Roaster 3 03/28/2016 04:40
SR500 Roasting opinions Roasting Coffee 4 02/15/2016 16:33
Member Poll
What is your usual batch size for roasting?



9 to 10oz

1lb to 1.5lb

2 to 3 pounds

over 3 pounds

You must login to vote.
You must login to post a message.

09/23/2017 07:49
mraphael Welcome

09/22/2017 13:26
Welcome Shangri-Brah

09/22/2017 13:23
welcome2 farmer coffee

09/21/2017 02:24
Welcome jawjatek

09/19/2017 17:50
sandbf Welcome

09/17/2017 12:59
welcome2 tultulini

09/16/2017 13:10
Welcome russ

09/16/2017 11:27
nickso Welcome

09/16/2017 11:25
daustin Welcome

09/16/2017 06:46
kerfboy welcome to forum

09/15/2017 02:31
welcome2 coffeeismagick

09/12/2017 08:46
Welcome Linnaeus

09/11/2017 17:18
Howdy John! beach

09/11/2017 10:24
Welcome cjpriebe

09/11/2017 10:23
Welcome Aucoffee