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HTC + TC4C installation questions
BarryR
Well, it's time to think about doing the install on my B-2K.
A few questions:

1) Are there any other board options that I should consider? (for example, can the RL-HT-CTRL board still be purchased)?
2) Am I correct that the boards likely will be available soon? (I think that's what I'm seeing on the mlgp-llc website.
3) Does anyone have specific directions particularly ones that would also tell me which parts to order for mounting, thermocouples, wiring, etc. so I don't have to figure it out myself?
4) Is this roughly a weekend project?

The excellent user guide leaves many options.
If anyone could point me to some additional info that would be greatly appreciated.
Barry
 
okmed
BarryR, there are many ways to skin the cat and people use what is available or what works easiest for them. I used Omega thermocouples (omega.com) and the particular ones I used are part #HTTC12-K-18G-2-GG. If you go to their website you will see that they are Hollow Tube Thermocouple Probes and have 12" leads- are type K- 1/8" diameter grounded- 2" long- with fiberglass insulated leads. They were not listed but were nothing special and they ordered them for me. Call them or email them if you want or need something different. I mounted mine using standard 1/8"MPT x 1/4" compression fittings. I ground down the 1/8" MPT side shorter and used 1/4" silicone tubing with nylon furrels to capture and hold the 1/8" thermocouples in place. I used a 11/32" drill and then a 1/8 NPT pipe tap to thread the holes and mount the fittings. The hardest part was feeding the wire leads throu the silicone tubing. It's like trying to push a string. Dish soap down the tubing helped.
If you have all the parts together it definitely should be doable in a weekend. Hope this helps.
okmed attached the following images:
thermocouple_mount.jpg thermocouple_comp_fitgs.jpg

RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
 
GreenBean
I believe that JimG has recently changed PCB fabricator. From the latest update on his website I expect he will be back in production soon. I made the RL-HT-CTRL boards available in small numbers as a stop gap measure whilst the other HTRI boards were unavailable. Now JimG is back in production I have no plans to supply any more.

Thermocouple installation on a Hottop involves a number of compromises. The best solution for you will depend on what compromises you prefer to make. I have been involved in many installations for various HTRI boards and have summarised the main issues to be considered and various solutions in the thermocouple installation guide page of the RoastLogger website. This links to various other coffee forum threads giving the views of others and their solutions. Once you decide on the solution you wish to adopt and have all the materials to hand installation can easily be completed in a weekend.
homepage.ntlworld.com/green_bean/coffee/smilestore/8.gif
Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Hottop P | Hottop B | French Press (several) | Aeropress (collecting dust) | Kettle modded (added digital thermometer)
 
BarryR
Thanks for all this great info. I'm reading the related posts and absorbing.

Why not purchase two of the OEM K-type thermocouples (from Hottop, or something very similar) which would thread right in and not require epoxy, etc.?

Are they not long enough?
If not, isn't there something just like them of a length that would work?
Barry
 
okmed
Barry, I believe Turtle used the OEM thermocouples ( see here http://forum.homeroasters.org/forum/viewthread.php?thread_id=2999&rowstart=80#post_51080 ). They are $40.00 from Hottop so that is a bit more than the $21.50 I paid for the Omega's. It definitely makes it easy to mount though. You might want to check with Randy from Hottop on the length of the leads to make sure they are long enough, or since you have the 2K model you can measure the lead for yourself.
RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
 
BarryR

Quote

okmed wrote:

Barry, I believe Turtle used the OEM thermocouples ( see here http://forum.homeroasters.org/forum/viewthread.php?thread_id=2999&rowstart=80#post_51080 ). They are $40.00 from Hottop so that is a bit more than the $21.50 I paid for the Omega's. It definitely makes it easy to mount though. You might want to check with Randy from Hottop on the length of the leads to make sure they are long enough, or since you have the 2K model you can measure the lead for yourself.

Yup, that picture is what I was thinking of doing.

I don't mind spending $40 extra (actually there's some hardware that I wouldn't need, I think).

I'll PM turtle for comments (unless he's reading this).
Anyone have other thoughts?
Am I looking for 1/2 inch protrusion into the chamber or as far as possible without hitting anything?
Barry
 
okmed
If you go with the OEM thermocouples the protrusion is already determined for you.
RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
 
BarryR
I know. What I'm wondering is whether it's the right amount of protrusion or not.
Barry
 
okmed
Ciel-007 posted this link to info about temperature probes. It mentions that 10x the diameter of the probe should protrude.

http://www.teaand...coffee.htm
Edited by JackH on 10/06/2014 6:16 PM
RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
 
JimG

Quote

GreenBean wrote:

I believe that JimG has recently changed PCB fabricator. From the latest update on his website I expect he will be back in production soon. ...


The bare boards now come from OSHpark, and are of higher quality than the previous supplier. In particular, OSHpark provides ENIG gold plating on all of the solder contacts, which is a premier product.

I now have a full supply of the bare boards for the TC4C. The TC4 shield blanks are running a little low, but new stock is already on order.

Jim
 
BarryR
Upon further reflection, it would seem that the OEM probes are on the short side.

I like the idea of compression fitting without epoxy, but I'm not sure if that's doable.

If I get something like the Omega probe with an Inconel collar, would that fit directly in a compression fitting or do I still need to epoxy it?

An an entirely different note: I'm comparing RoastLogger and Artisan. It looks like roast logger doesn't show the heat & fan settings on the roast graph and artisan does. Is that correct?
That would seem to give artisan a bit plus.
Barry
 
Barrie

Quote

BarryR wrote:

If I get something like the Omega probe with an Inconel collar, would that fit directly in a compression fitting or do I still need to epoxy it?


I have Omega probes with the Inconel collar and they are held in place by metal tubing through which they are inserted. One of the problems in their installation is that the collar has a little protrusion on the side, I think related to being cinched down on the wires. It is possible to file this down to align with the remainder of the collar. The problem I have encountered is that they read a little low, probably due to the mode of installation, but as they are consistent this is not a problem except for reporting purposes.
Barrie (San Diego, CA)
"So much to learn, so little time."
Hottop 2K+., Artisan, Jura Capresso ENA 3 (i.e. espresso).
 
woodchuck
Just to echo Barrie's note, I have the same probes. I ran them through a metal collar (rivet nut) into the chamber and sealed the extra space in the nut with high temp RTV. Mine read about 7F low with that configuration but as Barrie said they are quite consistent.

Cheers

Ian
Roasters: TJ-067, Hottop with TC4C and RAF Mods
Espresso: LaSpaziale VII/Macap M4 Grinder
Pour over: Bonmac Pro Cone
Press: Bodum
 
JimG
Have you tried disconnecting your laptop from AC power and running on battery?

Jim
 
BarryR
So, I saw the RAG, MikePetro, Frachlitz solution and okmed's above. All fairly similar though okmed's uses the 1/8th probe instead of 1/16th.

So, I'm deciding which diameter to use and will probably either use the HTTC24-K-116U-1.5-GG or the 1/8th inch version of that

This is the ungrounded and fiberglass covered version. If I get that, I would think I don't need to thread the wires through anything right?

Also, okmed mentions tapping a backnut and I think in other solutions they're tapping a hole in the backplate of the Hottop and threading the compression fitting through that. Is that right?

What's the silicone sleeve for?
Is it physically needed because the compression fitting's bigger than the probe, for temp isolation from the roaster or for electrical isolation (which I think I wouldn't need with an ungrounded probe)?

And, on a totally separate note: will roastlogger graph the fan and heat settings like artisan will?

Thanks everyone for all the great info.
There's no way I ever could have figured this stuff out myself.
Barry
 
okmed
I didn't use a back nut, I just tapped threads into the back plate. The silicone tube sleeve provides both electrical and thermal insulation. I needed the electrical insulation because my probes were grounded. I chose grounded probes for quicker temperature response. Using 1/4" compression fitting and 1/4" silicone tubing captures the 1/8" probes nicely.
RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
 
BarryR

Quote

okmed wrote:

I didn't use a back nut, I just tapped threads into the back plate. The silicone tube sleeve provides both electrical and thermal insulation. I needed the electrical insulation because my probes were grounded. I chose grounded probes for quicker temperature response. Using 1/4" compression fitting and 1/4" silicone tubing captures the 1/8" probes nicely.


OK. I think I almost got it. A few more questions though:
You said you used 1/8 inch NPT on the compression side. How does a 1/8" probe fit inside 1/4" tubing with a ferrule (or am I misunderstanding something here).

Also, what tubing and ferrule do I need (just want to get them ahead of time if I can't source them locally).

If I get the fiberglass covered probe doesn't that mean I don't have to shove the wires through the silicone?

Do you find that the backing plate is thick enough to sustain the threads and the fittings?

Finally (maybe): I don't have anything to grind the fittings. Is this necessary or does it just reduce heat sink mass?

Thanks!
Barry
 
okmed

Quote

BarryR wrote:

[quote]okmed wrote:


OK. I think I almost got it. A few more questions though:
You said you used 1/8 inch NPT on the compression side. How does a 1/8" probe fit inside 1/4" tubing with a ferrule (or am I misunderstanding something here).


Yes welcome to the wonderful world of pipe thread sizes. The opening in the 1/8" NPT fitting has about 1/16" clearance around the 1/8" probe. Go to Home Depot with a ruler and measure up the fittings for yourself so you have a clear understanding.


Also, what tubing and ferrule do I need (just want to get them ahead of time if I can't source them locally).


As I said in my previous post, I used 1/4" OD silicone tubing which fits a 1/4" compression fitting and used nylon furrules instead of the brass ones that come with the compression fitting. 1/8" probes will fit inside the 1/4" silicone tubing with a little dish soap to help it slide. You actually only need about 5/8" to 3/4" of silicone tube to fit inside the compression fitting to act as thermal and electrical insulator.


If I get the fiberglass covered probe doesn't that mean I don't have to shove the wires through the silicone?


I have not seen this fiberglass covered probe so I can't answer that.


Do you find that the backing plate is thick enough to sustain the threads and the fittings?


So far the 1/8" NPT is holding fine in the backing plate.


Finally (maybe): I don't have anything to grind the fittings. Is this necessary or does it just reduce heat sink mass?


You can use a hacksaw and a file or not. If you don't shorten the thread then don't run the tapered tap through as far. You don't want too much thread protruding into the roaster. Also, I think 1-1/2" probe won't be long enough. You want the compression furrule to be around the tube and the probe.


Thanks!

Edited by okmed on 10/14/2014 12:03 AM
RAF-1 Extreme (modified B-2K) Hottop with HTC+TC4C, HG-One grinder, Bezzera Strega.
 
GreenBean
I see that you have started a thread on another coffee forum discussing this same subject i.e. advice on installation of thermocouples in your Hottop. It is difficult to follow your current thoughts on what you propose to do across the two threads. There are many different approaches possible and you have received good advice from a number of contributors. The solution proposed by okmed looks good to me provided nylon ferrules are only used on the cold side of the fitting. My views on what I perceive to be your current proposal are:

1. There is no substitute for dismantling and measuring your Hottop with your proposed solution in mind. I believe Hottop have made changes to the design of key elements such as the drum. Measuring your own Hottop is the only way to be certain that your solution will fit.

2. Choose the thermocouple length to allow maximum safe protrusion into the roast chamber. This will provide the most accurate readings. The drum drive motor can be disconnected to allow the insertion or removal of the thermocouple.

3. My view is that 3 mm diameter probes offer the best compromise of smooth output, speed of response and robustness (of the sheath and thermocouple wires). 1/16? thermocouples will work but you should expect less smooth temperature and RoR curves and may have issues with breaking thermocouple wires.

4. Fibreglass insulation provides good thermal insulation to the thermocouple wires but is not ideal to insulate them electrically from any mains connections within the roaster. To ensure a safe installation you should route fibreglass insulated thermocouple leads through suitable silicone sleeving/tubing.

5. The rear wall of the Hottop is too thin to provide a robust threaded connection to the fitting although okmed reports good results so far. The connection may well fail after a time. In this case you would still have the option to fix it with J B Weld.

You have asked if RoastLogger will graph the fan and heater settings. I have deliberately made the decision not to chart this information as I believe it encourages users to think, and attempt to control their roaster, based on elapsed roast time. Elapsed roast time is a poor indicator of roast stage and attempting to control a roast based on this produces poor results. I have covered my views on this in several posts on other coffee forums. In summary, RoastLogger allows you to control the roast by making changes to the heater and fan based on bean temperature. This produces much better control of a roast and more consistent results in the cup. RoastLogger provides a simple set of tables that allow you to script the changes in settings. These changes are applied exactly as scripted in each roast and RoastLogger indicates when each change is applied. Charting this would not provide any additional useful information.
homepage.ntlworld.com/green_bean/coffee/smilestore/8.gif
Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Hottop P | Hottop B | French Press (several) | Aeropress (collecting dust) | Kettle modded (added digital thermometer)
 
MaKoMo

Quote

GreenBean wrote:
3. My view is that 3 mm diameter probes offer the best compromise of smooth output, speed of response and robustness (of the sheath and thermocouple wires). 1/16? thermocouples will work but you should expect less smooth temperature and RoR curves and may have issues with breaking thermocouple wires.

+100 to this. I got noticed rather often by people that plan to move to thinner probes to improve on speed. I also get noticed rather often by people that fight with noise and spiky curves (especially RoR curves). Rather often I get those notices in short temporal distance from identical people.

Having experiences a number of different probe setups I double this. 3mm are an excellent compromise for the task of roasting coffee. And yes, it is a compromise, not optimal in speed nor smoothness.
 
BarryR

Quote

GreenBean wrote:

I see that you have started a thread on another coffee forum discussing this same subject i.e. advice on installation of thermocouples in your Hottop. It is difficult to follow your current thoughts on what you propose to do across the two threads. There are many different approaches possible and you have received good advice from a number of contributors. The solution proposed by okmed looks good to me provided nylon ferrules are only used on the cold side of the fitting. My views on what I perceive to be your current proposal are:

1. There is no substitute for dismantling and measuring your Hottop with your proposed solution in mind. I believe Hottop have made changes to the design of key elements such as the drum. Measuring your own Hottop is the only way to be certain that your solution will fit.

2. Choose the thermocouple length to allow maximum safe protrusion into the roast chamber. This will provide the most accurate readings. The drum drive motor can be disconnected to allow the insertion or removal of the thermocouple.

3. My view is that 3 mm diameter probes offer the best compromise of smooth output, speed of response and robustness (of the sheath and thermocouple wires). 1/16? thermocouples will work but you should expect less smooth temperature and RoR curves and may have issues with breaking thermocouple wires.

4. Fibreglass insulation provides good thermal insulation to the thermocouple wires but is not ideal to insulate them electrically from any mains connections within the roaster. To ensure a safe installation you should route fibreglass insulated thermocouple leads through suitable silicone sleeving/tubing.

5. The rear wall of the Hottop is too thin to provide a robust threaded connection to the fitting although okmed reports good results so far. The connection may well fail after a time. In this case you would still have the option to fix it with J B Weld.

You have asked if RoastLogger will graph the fan and heater settings. I have deliberately made the decision not to chart this information as I believe it encourages users to think, and attempt to control their roaster, based on elapsed roast time. Elapsed roast time is a poor indicator of roast stage and attempting to control a roast based on this produces poor results. I have covered my views on this in several posts on other coffee forums. In summary, RoastLogger allows you to control the roast by making changes to the heater and fan based on bean temperature. This produces much better control of a roast and more consistent results in the cup. RoastLogger provides a simple set of tables that allow you to script the changes in settings. These changes are applied exactly as scripted in each roast and RoastLogger indicates when each change is applied. Charting this would not provide any additional useful information.


Again, thank you all for all the info.
I was concerned about the "cross-posting" issue though I kinda stumbled into it.
A helpful post above led me to the HB threads, so I asked some questions on those threads on HB. I'm not sure how I should have handled it differently. I guess by commenting on those threads here (though I wasn't sure that those members would respond here).
Sorry if I violated forum etiquette.

This probe thing is way more complicated than I'd imagined. Before I delved, I figured I'd just be buying 2 probes, drilling and installing. Though I'm a good DIYer I'm not an engineer and don't know some of the terms and details and never worked with probes, thermal insulation and the like.

Isn't fiberglass an electrical insulator?

In regards to the other info above:

1) I realize I have to do it myself, measure, etc, but had hoped I could figure out the parts before disassembling otherwise I'll pretty much have to take it apart, figure it all out, put it back together and then order the parts.

3) Oh well. Looks like I have to rethink this all. : )

4) Isn't fiberglass an electrical insulator?

5+) I only wanted the fan and heat indicators as a reference to make it easy to review, see what the roaster was doing and then make changed either to the profile before the next roast or during the next roast on the fly, but I'll see how it all goes when I finally get this mod done.
Barry
 
GreenBean

Quote

BarryR wrote:
4) Isn't fiberglass an electrical insulator?

Yes, fibreglass insulated thermocouple leads use thin layers of woven fibreglass which is adequate for most circumstances but they are susceptible to being ?punctured? by sharp edges. When routing such leads through a roaster containing exposed mains voltage connections you should, for your own safety, ensure that the thermocouple leads can not come into contact with these connections. The easiest way to do this is to route the thermocouple leads through more substantial insulation sleeving.
homepage.ntlworld.com/green_bean/coffee/smilestore/8.gif
Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Hottop P | Hottop B | French Press (several) | Aeropress (collecting dust) | Kettle modded (added digital thermometer)
 
BarryR
Thanks GreenBean and everyone else.
Based on the advice in this post, I'm reconsidering going with larger diameter probes as you suggest. Hopefully, this weekend, I can reach a decision and order everything.

If I do go with wider probes it seems two major options are either the XCIB-K-3-5 that seems to be highly regarded in the various threads
or the HTTC12-K-18U-2-GG (1/8" ungrounded probe).

The XCIB is 6.4mm diameter with an exposed tip, so I imagine this would combine the benefits of ungrounded (not needing grounding) with the rapid response time that the exposed tip provides.

The HTTC 1/8" (ungrounded), would probably be easier to mount (it's narrower) but would not have the above XCIB advantages. It's also cheaper.

1) Do I have this about right?

2) Has anyone mounted the XCIB type without the epoxy? If so, which thermocouple or other method was used.

3) If I use the 1/8th" HTTC type, I can use 1/4" compression fittings, right?
Any down side? Is there room? Would brass be a problem (Stainless seems very expensive for this).

4) I recall on poster epoxying a sleeve but then holding the probe itself in place with basically friction fitting in a silicone (or such) sleeve. Wouldn't this tend to shift?

5) I believe the XCIB is stated to be very durable but for the BT probe, wouldn't the beans constantly banging into the exposed tip put it at risk for breaking?
Barry
 
BarryR
Sorry.
I reread OKMed's post and see he pretty much answered #3 above.
Barry
 
GreenBean

Quote

BarryR wrote:
...The XCIB is 6.4mm diameter with an exposed tip, so I imagine this would combine the benefits of ungrounded (not needing grounding) with the rapid response time that the exposed tip provides.

The XCIB thermocouples have an exposed tip which is insulated from the collar and braiding so they do not require further electrical insulation. The rapid response time due to the exposed tip is a disadvantage for this service. A slower response is desirable to obtain smooth output as discussed in previous posts in this thread.

Quote

BarryR wrote:...Has anyone mounted the XCIB type without the epoxy? If so, which thermocouple or other method was used....

I am not aware of anyone doing this. I think the best and easiest way to fix these thermocouples is to J B Weld them directly to the rear wall.

Quote

BarryR wrote:...I recall on poster epoxying a sleeve but then holding the probe itself in place with basically friction fitting in a silicone (or such) sleeve. Wouldn't this tend to shift?...

Silicone tube can grip the thermocouple tightly If the tube and the fitting are sized correctly to provide a tight fit. If a tight fit is not achieved then the bean probe would certainly shift. The solution used by okmed resolves this by using a nylon ferrule in a compression fitting to compress the silicone tube against the sheath.

Quote

BarryR wrote:...I believe the XCIB is stated to be very durable but for the BT probe, wouldn't the beans constantly banging into the exposed tip put it at risk for breaking?

The XCIB thermocouple uses quite thick wire with a substantial bead at the hot junction. This may not be as robust as a 3mm stainless steel sheath but is sufficiently robust for the service.
homepage.ntlworld.com/green_bean/coffee/smilestore/8.gif
Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Hottop P | Hottop B | French Press (several) | Aeropress (collecting dust) | Kettle modded (added digital thermometer)
 
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