How does a propane themostat work

Discussion in 'Propane Smokers' started by jbpace, Mar 12, 2008.

  1. jbpace

    jbpace Fire Starter

    I'm trying to figure out how to add a thermostat to a propane smoker. I'm seeing the threads discussing the topic, but I'm not sure they solve my issues.

    First, I need something that works with no power. It's got to work at camp in the woods, so I'll have no electricity - just propane. I was planning to use the gas control valve (2E854) & pilot w/ 750 mV generator (1RC59) from Grainger, but I don't understand the thermostat hookup. Do traditional two-pole oven thermostats require external power? If so, what type of thermostat doesn't need external power?

    Thanks,
    Jon
     
  2. richtee

    richtee Smoking Guru OTBS Member

    A heater type 'stat uses the millivolt levels output by a pilot/thermocouple to control the valve. But a 12V battery will operate a standard 24VAC control valve.
     
  3. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    Hey Richtee, can you explain the heater type stat again. I am a master electrician, but I've been doing more plumbing lately, LOL. Are there gas valves that can regulate temperature without electricity, using bi-metal type controls or something like that?
     
  4. richtee

    richtee Smoking Guru OTBS Member

    I suppose so that has to be how they work. A series connection with the thermocouple?
    "Yes...we have pilot...yes..we need heat.." CLICK.
     
  5. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    Really man, I am drawing a blank---I am really confused. Are there gas valves that can regulate temperature without electricity by using mechanical means such as bi-metallic or fluid controls?
     
  6. richtee

    richtee Smoking Guru OTBS Member

    The millivolt levels apparently are enough to operate a gas valve.
     
  7. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    Richtee, Do you know what generates the milivolts? I think I pickled that part of my brain years ago:)
     
  8. richtee

    richtee Smoking Guru OTBS Member

    The thermocouple itself. It's two dissimilar metals that when heated generate a voltage across the junction.
     
  9. richtee

    richtee Smoking Guru OTBS Member

    http://en.wikipedia.org/wiki/Thermocouple
    On edit an excerpt " Some systems, known as millivolt control systems, extend this concept to the main gas valve as well. Not only does the voltage created by the pilot thermocouple activate the pilot gas valve, it is also routed through a thermostat to power the main gas valve as well. Here, a larger voltage is needed than in a pilot flame safety system described above, and a thermopile is used rather than a single thermocouple. Such a system requires no external source of electricity for its operation and so can operate during a power failure, provided all the related system components allow for this. Note that this excludes common forced air furnaces because external power is required to operate the blower motor, but this feature is especially useful for un-powered convection heaters.
     
  10. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    Thanks Richtee,

    I kind of figured that was what you were going to say---I probably learned that before, but ya know how it goes, if ya don't use it, you lose it.

    I guess I have to do some research on valves, because it sure would be nice to set up my dutch oven and side burners for deep frying so when pre-heating I can walk away not worrying that I'll go over 400 degrees on the oil.

    Thanks,

    Steve
     
  11. richtee

    richtee Smoking Guru OTBS Member

    Yer welcome, man... I'll take a nice cobbler for payment :{)
     
  12. frybob

    frybob Fire Starter SMF Premier Member

    I purchased this valve from the below listed website and it works like a champ. I installed it in my fridge converted smoker. It was very easy to install. It seems to only fulxuate about 2 degrees. I really love it. It is the best $30 I've spent on my smokers.

    http://www.turkey-fryers.com/scb001_...trol_valve.htm

    I highly recommend it,

    Bob
     
  13. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    Thanks FrybBob, just amazing, you dream it, and they already have it---or maybe I have alzeimers!!! Thanks for the Link:)

    Richtee, I have a problem...................

    UHM, I had to look up the word "cobbler", It seems that i have forgotten what it was,so, uhhm, which one of these do you want??

    cobbler |ˈkäblər|
    noun
    1 a person who mends shoes as a job.
    2 an iced drink made with wine or sherry, sugar, and lemon.
    3 a fruit pie with a rich crust on top.
     
  14. richtee

    richtee Smoking Guru OTBS Member

    LOL welll they named the crust after me...so take a guess!
     
  15. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    I'll guess, I know I love the new souls I just got for my work boots!!
     
  16. richtee

    richtee Smoking Guru OTBS Member

    Cobbler is a time honoured dutch oven dessert..sooo good!
     
  17. ds7662

    ds7662 Smoking Fanatic OTBS Member

    Yes there are thermocouples that require a pilot of normal size with a slight yellow tip on the flame to make the the gas valve work......then there are thermopiles that require a larger pilot with an all blue flame, that generate even more millivolts.

    The thermocouple models generally have the t-stat built into the valve with a probe that can be placed where needed. These are not the same as say a wall mount t-stat that actually has a temp setting with numbers on it.

    The thermopile generates more voltage there for allowing it to use the familar wall thermostat. The voltage takes care of opening and closing the gas valve as well as working the t-stat.
     
  18. smok'n steve

    smok'n steve Smoking Fanatic OTBS Member SMF Premier Member

    Nice Explanation,

    I finally realized, like with heating t-stats, they can be either on or off, valve open or closed, this is only possible because of the pilot being available for ignition at all times. I think---
     
  19. jbpace

    jbpace Fire Starter

    For better or worse, I've ordered all the parts I think I'm going to need. I appreciate all the help you guys gave me. I'll try to document the mod when I assemble it after all the parts arrive over the next week.

    Wish me luck (e.g. no BOOM!),
    Jon
     

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