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My DIGITAL Stovepipe thermometer build

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by scooby074, Feb 7, 2013.

  1. scooby074

    scooby074 Feeling the Heat

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    As an offshoot of this thread http://www.hearth.com/talk/threads/...rmometer-alarm-yet.101851/page-3#post-1365214 I figured I'd make a build thread on building my own version of a digital stove thremo. I do not have all my parts yet so this is just a list of what's on order so far.

    The unit will have 2 Pids. One for stove top and one for stove pipe.
    There will be a switch to arm/disarm the alarm.

    So time for a parts list.

    PIDS, the common Rex C100's. http://www.ebay.ca/itm/221101970614?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    LED/Alarm , same as what Auber offers http://www.ebay.ca/itm/250983481063?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    Stack Thermocouple, 1250*C rated, 100mm long. http://www.ebay.ca/itm/251209855097?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    All going to be mounted in an Aluminum Hammond enclosure. Darn enclosure and misc electrical bits cost more than the pids and other parts above!<> But I think it was worth it to spend money on a nice enclosure, because it is what's going to be seen. ALl electrical bits are from Digikey.ca. They offer the best Canadian shipping BY FAR!

    Enclosure, http://www.digikey.ca/product-search/en?x=5&y=21&lang=en&site=ca&KeyWords=1455T1601BK-ND
    [​IMG]


    Box is on back order till the middle of the month :confused: so its going to be a while before I get to finish it. I cant wait to get it built. Do to operator error, the stove has gotten away from us a few times (people throwing wood on, but not watching) , the alarm will help.
    northernontario likes this.

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  2. Mitch Newton

    Mitch Newton Member

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    Can't wait to see pics of the finished product.
  3. raybonz

    raybonz Minister of Fire

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    Think you're gonna peg that controller out with the stack probe as it only goes to 732 degrees F.. If you monitored the surface temp you would be OK though.. That temp control is great deal if it works properly..

    Ray
  4. scooby074

    scooby074 Feeling the Heat

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    Yes the REX is rated to 450C "by the book", but there is supposed to be a "hidden" menu that will allow you to change that, like you can on higher end models. Apparently the "guts" are shared across models and manufacturers, who then add or remove features to get the controller to the right price point, but the programming remains, its just hidden and password protected.
  5. scooby074

    scooby074 Feeling the Heat

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    Yeah me neither :) Now, just playing the waiting game for stuff to arrive on a slow boat. Sucks.
  6. WES999

    WES999 Minister of Fire

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    Hope you can figure out how to set the controller to read higher than 750::F for the flue.

    I ordered one of those thermocouples, the work fine but I chose to use this one from Auber:

    http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=22

    It was a bit more expensive but the hole required in the flue is a lot smaller and the response time is much better.

    I know I mentioned it in the other thread but here it is again.

    I can almost guarantee one day you will forget to turn on the alarm switch, and that is when you will need it.

    If you add a relay as it the pic you can silence/acknowledge the alarm , but the alarm will reset when the temp
    falls below the high limit. No worries about resetting the switch.

    Good luck.

    img_switch_vs_ots.gif
  7. scooby074

    scooby074 Feeling the Heat

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    Guys, I need some advise bad!!

    Went to the mailbox today and it was open! As in, the front door to the whole mailbox was not locked!!! and swinging in the breeze. For you guys in the US, I dont think you have our style of rural "super" mailboxes where several people share one common box, that has individual boxes within it. Pic below. When the mailman comes, he uses his key that opens the entire front door so he can fill the boxes without it taking too long.

    [​IMG]

    Now what Canada post does is put any parcels in the large box (left picture, bottom row) and put a key in your personal box (smaller boxes) that fits the "parcel" box. They used to send these parcels to the main post office for pickup, now only extremely large parcels have to go to the post office building.

    Now guess what... thats right, there was the key to the parcel box in my personal box. That means I had a parcel! But the front door of the mailbox was open (all boxes on the left hand mailbox were open to the outside, including the parcel box) and there was nothing in the parcel box!

    I imagine that that parcel was one of the ones I was expecting for my build!

    I called canada post, and they sent out an investigator who said i need to contact the shipper.. except I have no idea what parcel it was (expecting 3). And it gets better, the delivery guy that day was a substitute. Which explains why he forgot to lock the main door. Anyways they wont take any responsibility for their obvious negligence, nor do they know what parcel it was. Im so friggin pissed!

    What do I do now? Should I wait till the remaining parcels come in, so I know whats missing? Should I file a claim with paypal? Do I have a time limit? Its not really the shippers fault that it got lost, its the damn post offices fault..

    Im not a regular on ebay, only a few purchases that went through without problems, so any advise here is appreciated!!
  8. scooby074

    scooby074 Feeling the Heat

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  9. scooby074

    scooby074 Feeling the Heat

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    The remaining 2 ebay parcels arrived today. Thankfully the PIDs were one of them! The alarms came too. That means im missing the high temperature thermocouple. Im going to wait a bit and see if it turns up, if not I'll re-order either from ebay or Omega. Still waiting for the aluminum case to get off back order though.

    I was so excited, i did a rough setup to test out the PIDs (make sure they weren't DOA) and the alarms. So far, I like it!



  10. scooby074

    scooby074 Feeling the Heat

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    The stovepipe thermocouple arrived by mail!! But that begs the question, what unexpected package am I missing? :confused:

    I also got the backordered enclosure and other parts from Digi-Key. If any Canadians are looking for electronic parts, I can't say enough good things about Digikey. Once the non-stocked enclosure was in stock, the order was shipped FAST and cheap. $8 overnight courier shipping is UNHEARD of in Canada.

    I started building the stand today and had some issues cutting the enclosure for the PID's. Pics to follow tomorrow.
  11. scooby074

    scooby074 Feeling the Heat

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    Project is 99% finished and functional. Just need to finesse the stovetop and stovepipe mounting. I figured out the programming for the PID to have it read and alarm at temperatures over 400*C. I describe the procedure to make that change in a video to follow.

    Construction pics and descriptions:

    First thing to do was make a stand. I made it out of 3' of 1" sq tube and some 3/8" rod to make the scroll feet. My first time doing a scroll. Not to bad. Although Ive welded and metalworked for years, blacksmithing is something new I'd like to try. I plan on building a small propane forge someday (hopefully soon) and will likely make a fireplace set as my first project. More on that later ;)

    [​IMG]

    A little black spraypaint:
    [​IMG]

    Now on to the PID mount and assembly:

    Enclosure is the aluminum Hammond from the first post.
    Tape is your friend! Aluminum is soft and scratches easily. Plus its just easier to layout on tape.
    [​IMG]

    Layout. Will be self explanatory when you see the finished product.
    [​IMG]

    I cut out the holes (44mmx44mm IIRC) for the PIDS using a body saw. Even though I supported the aluminum disaster happened! The aluminum is thin and I must have flexed it a bit too much. It tore. So I tried using JB Weld, which I let setup yesterday. Tried to file smooth it out today with a file and it broke again :mad:...First time JB Weld let me down
    [​IMG]

    [​IMG]

    So what now? I got out the SuperT and Activator. This is the best stuff ever! Its saved my ass so many times. Ive fixed broken auto sensors to computer cases with the stuff. Think of it as Crazy Glue that actually works! The activator is key to its performance.
    [​IMG]
  12. scooby074

    scooby074 Feeling the Heat

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    Start of the PID assembly

    The PIDs come with a bracket that locks onto the body of the PID and has fingers that press against the faceplate of the enclosure to keep the pids tight in the holes. Unfortunately the enclosure I used just barely clears the PIDS and the brackets wont work. If your building one of these, get the next size bigger enclosure.
    [​IMG]

    So how will I keep it tight? Superglue to the rescue (again)

    I cut the sides out of the brackets and glued them to the sides of the PIDS to keep them tight in their holes. This means that if a PID has to be removed, I'll likely destroy it in the process because its completely glued in. Hope I never have to go through that, lol.Oh well, the PIDs are cheap anyways. The white stain is caused by the activator. Its the one downside to using it
    [​IMG]

    Activated glue squeeze out on face. Oh oh:(
    [​IMG]

    Face masked and painted to cover some scratches and glue squeezeout.
    [​IMG]

    Rear "inputs" layout. From L-R 2 thermocouples. On-Off switch. Fuse. 120V in. Try to keep the TC input as far as possible from the 120V to limit interference. Kinda hard in a small enclosure, but at least I tried.
    [​IMG]

    Rear drilled. All drilling was done with Unibits. Dont try to use a regular twist drill, there is a good chance it will bite and twist the Al all up. All holes should be de-burred too.
    [​IMG]

    Rear with fittings installed:
    [​IMG]
  13. scooby074

    scooby074 Feeling the Heat

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    On to the wiring.

    Rear with "input" wires installed. Solder is used for the connections from the 120V in to the switch and fuse. Power cord is a 3 prong grounded cord like you'd see on a computer. Grounding the chassis is essential!
    [​IMG]

    Front wiring. 120v is run from L-R. It should be pretty clear in the pics. 120VAC is ran to both of the PIDS and to the armed indicator. On these PIDS 120V must be run to one side of the alarm relay for it to function. The switch in the bottom centre is a DPST that functions as an alarm disable. There is an indicator light above it to show that the alarm is armed. I could have made this a whole lot more complicated with latching relays or Time delays but why bother? The big blue indicator LED should suffice. The front panel is connected to the rear panel via stakon connectors to allow for future disassembly if needed.
    [​IMG]

    [​IMG]

    [​IMG]

    Alarm buzzer and indicator are mounted to the top of the enclosure. There was no room on the face. I think it will work better there anyways because the sound should travel better. I took care to ensure that the PIDs, switch and wiring would clear the alarm buzzer when the face was installed. It's mounted in the centre,L-R and 60mm back from the face.
    [​IMG]
  14. scooby074

    scooby074 Feeling the Heat

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    Finished product Rear:
    [​IMG]

    Finished Front:
    [​IMG]

    All told it took close to 8 hrs to build, maybe a bit more.

    Videos of operation and programming to follow.
  15. scooby074

    scooby074 Feeling the Heat

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    Something Im working on for the stove top TC. Its going to have a rare earth magnet base (hopefully it can stand the temps) and spring loaded TC. More pics to follow

    [​IMG]
  16. scooby074

    scooby074 Feeling the Heat

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    Some Video:

    First startup. Notice Default max setting of 400*C
  17. scooby074

    scooby074 Feeling the Heat

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    First high temp test. Notice flashing display indicating that the TC is over factory default max temperature. The display still reads correct however.
  18. scooby074

    scooby074 Feeling the Heat

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    Changing the high limit to match the limit of the high temperature thermocouple. As I said, these units have a "secret" or "hidden" menu where you can change most of the parameters on these PIDs. To access this menu, the standard menu has to be set to Lck 0000 (IIRC. I have to confirm). Then you go into the "hidden" menu by pushing "set" and "left arrow". Then you can set Cod in the hidden menu to 0001 and exit. The next time you enter the "hidden" menu you have access to these parameters which are in addition to the standard "hidden" menu. There are at least 2 "hidden" menus.

    These PIDs have many of the features of the expensive PIDs, they are just disabled in software. I havent tried it, but I believe you can even change the style of TC (J type instead of K type for example) and other functions. It can also be made to read in *F, again I havent tried to figure that out yet either. But I'll keep playing with it:)

  19. scooby074

    scooby074 Feeling the Heat

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    Testing after raising SLH to 1250. Notice no blinking over 400 and the ability to set the SV to above the 400 default.

    northernontario likes this.
  20. scooby074

    scooby074 Feeling the Heat

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    Some updates.

    I finished the stovetop and stack mounts.

    [​IMG]

    Closeup of the stovetop mount. Its spring loaded to keep the TC tight to the stove. Rare earth magnet to keep it tight (more on that later)
    [​IMG]

    Stovepipe mount.
    [​IMG]

    Stovetop on stove. It worked fine until the temp got up to about 150*C then it suddenly lost magnetism. Not good. Need to find something that can take the temps. Currently I have the base under my steamer to keep it in contact.
    [​IMG]


    [​IMG]


    Working fine!
    [​IMG]
  21. scooby074

    scooby074 Feeling the Heat

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    A video of it hooked up and running. For some reason the background was very dark. Not sure why but maybe the blue indicator LED was messing with the camera's contrast or something like that?




    Now to get started and finish my build of the hearth area. lol
  22. Adabiviak

    Adabiviak Feeling the Heat

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    That's pretty cool. Funny that the magnet ate it with some heat, but cool nonetheless.
  23. Redlegs

    Redlegs Feeling the Heat

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    Wow. I just throw wood in my stove. You've taken this thing to a whole new level. Congrats on the build.
  24. scooby074

    scooby074 Feeling the Heat

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    Thanks!

    Its more a piece of mind thing for me. Too many times have the family thrown wood on the stove and walked away to do other things with the damper fully open. Temps have gotten dangerously high. This will serve as a backup so that if somebody walks away and forgets the stove the buzzer should remind them. My daughter already knows what to do if the alarm goes off.
    Redlegs likes this.
  25. WES999

    WES999 Minister of Fire

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    Excellent job! It is nice to have everything all in one enclosure, a lot neater than what I have. Nice build description. It does look like a tight fit, ever notice that there is always less room than you thought.:rolleyes:

    It is great that you were able to get the
    PID's read higher than 400::C. Can thy read in ::F rather than ::C?

    I use the waterjet at work to cut out panels, makes things really easy. You might try a dremel tool with a cut off wheel or a hand held nibbler, a bit gentler than a saw.

    Here is some info on magnets: http://www.mcmaster.com/#rare-earth-magnets/=lpai4z
    some rear earth magnets are only good to 300 ::F. Alnico magnets are good to 975::F.
    The one I used is Master Magnetics #07270 , The TC is from http://www.ppe.com/
    #WTCK-160. Works well.

    Now some ideas for the upgrades:
    Latching relay
    Have the stove top PID turn on the blower on high temp alarm.
    Have the flue temp PID automatically close the air control.






    Picture 115.jpg Picture 033.jpg

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