# Automatic Temp. Controll On Gosm Propane



## setitandforgetitsmoker (Feb 4, 2008)

hello, i recently purchased a smoke hollow propane smoker i belive it is identical to the gosm. i used it several times to make varios things. then i tried to make a batch of beef jerky with a maverick redi check remote temp sensor as my only way to verify temp. to keep smoker at 150 deg. was very challenging. so i decided to try and put a digital pid controller on this unit with propane. i bought a dwyer 2500 pid off e-bay for $50.00 then purchased a 24 volt gas valve off of used home furnace $25.00 with pilot light. this smoker will hold temps better than my commercial oven. now when i make jerky i enter the desired temp into the temp controller say 150 deg and it will maintain this temp with propane. i looked all over the internet to try to find someone that had made this mod and had no luck this is why i am posting this. now whatever i make i just sent temp and forget about it. i will put jerky in before i go to work come home and it is pretty close to being done no hassel no worries. and still very simple. i hope this post was usefull to you. thank you


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## charles1056 (Feb 4, 2008)

I would love to see some pics of these mods and get more details on the devices used and how to hook them up.


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## setitandforgetitsmoker (Feb 4, 2008)

i am going to hopefully soon have some pics up here i can tell you how to hook up the only thing remotely hard is plumbing in the gas valve and pilot which for me was very easy just took a little time.


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## setitandforgetitsmoker (Feb 4, 2008)

i failed to mention that 2 weeks ago it was very cold here like -15 with wind chill i had alot of wind gusts on smoker while the entire time it maintained temp 150 deg. made very good batch of jerky. thank you


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## sparky30_06 (Feb 4, 2008)

Greeat idea can't wait to see pictures and it makes total sense only question is how well does it smoke??  do you still get a good smoking from the wood???


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## richtee (Feb 4, 2008)

This is basically how my large smoker will run, except I am using a half a furnace heater  assembly, and it's regulator/valve.

Stop by roll call and give us an intro post too!


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## setitandforgetitsmoker (Feb 4, 2008)

it smokes very good i generaly only put the real heavy smoke on for 20-30 min at start up 20-30min in the middle and finish to taste that is on jerky but what i have found in the smoke hollow is to use really dry wood ive been useing hickory and apple that are real dry. seasoned and stored inside.when i use this wood and dont use the cover over the smoke box it will chug right along untill all wood is burned to ash. i also might add that i get a pretty good fire going in the smoke box with some pretty good size chuncks (2inch dia) before placeing into smoker. the gas will still keep the smoke going well though if that is what you want to do. i did find that these units dont allow as much air into smoke box as others but seems to do ok thank you


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## walking dude (Feb 4, 2008)

we prefer q-view.......PICS............sounds great dude...........

make sure you stop into roll call and introduce yourself, so we can give a proper welcome


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## kookie (Feb 5, 2008)

Sounds like a great idea. Wheres the q-view? 

Kookie


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## trent (Feb 5, 2008)

I was thinking (oh no) about automatic temp control for my GOSM.  I have seen the gas valve approach which is essentially controlling the temperature by turning the flame on and off (similar to stomp the gas and stomp the brake with no in between).  I am not knocking this approach as I haven't tried it.

Has anybody tried to control the gas flow through something like a mass flow controller?  Has anybody tried to activate the vents electronically with servos?


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## richtee (Feb 5, 2008)

Stop by Roll Call forum and give us an intro, then search username Geek with fire.


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## setitandforgetitsmoker (Feb 5, 2008)

Trent this is not at all hit the gas then the brakes. a mass flow valve or proportional valves are very expensive and if you set this system up to be stop and go you will short cycle everything. and compromise saftey my flame runs about 90% of the time and only shuts off and on as needed not very often. i can still regulate my flame with the original burner valve. when i design or build anything i want it simple effective and very reasonable expense here i have done all of these items.


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## trent (Feb 5, 2008)

setitandforgetitsmoker, thanks for the reply.  My challenge is to keep the temperature down, so my setting is usually as low as it gets.  As the meat cooks, the chamber gets warmer and I have to open the top vent and eventually don't have any control to keep the temperature down. 

I have just discovered the needle-valve solution to lower temps in the forums.  I understand your duty cycle of 90%, but how long does the burner stay off worst case?  Doesn't this slow your cooking time?  What is the hysteresis on the off-on transition?

Has anyone ever tried controlling a needle valve with an RC servo that you know of?  It seems that would be cheap.

Please, I wasn't criticizing your design.  You did a great job on it.  I was just looking at a different approach.


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## geek with fire (Feb 5, 2008)

The only thing to keep in mind is that most RC servos are 5V and just don't have the oompa to move a valve.  However, there are some 12 volt servos out there that you could gear reduce to move the valve.  I did some research some time ago and found a solution in the works:
http://www.rasdoc.com/paul/rockets/ballvalve.html
Expensive though.

Another solution is to use a stepper motor and an encoder to control the closed to full position.


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## setitandforgetitsmoker (Feb 5, 2008)

trent the temp controller pid has a type j thermocouple (temp sensor) that sets inside the smoke box that is what clls for heat like a thermostat in your home so no matter what happens with your meat or outside air temp wind etc. this set up runs at what temp values that i enter. imagine this for burner run time and number of time that my gas valve cycles. that when you dial your smoker in at say 225 deg  it may stay there untill meat warms up and then you have to start adjusting either air or flame all the way through cook. i dial my flame and temp in to get close to temp where it would probably hold for sometime without pid. now this chugs right along on my desired flame and rarely cycles on and off butwhen temp hits pre set value off it goes. and when it hits low set it comes back on.no real short cycles even at the end of cook. there are other ways to automate gas valves with pids this just was easy safe and cheap and yet very effective.


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## trent (Feb 6, 2008)

Geek, thanks for the link.  It looks promising, though I thought the cheapo servos were under $20.  I was talking to some engineering buddies of mine and one of them was saying ball valves do not have much flow control, at least not proportional or linear.  Perhaps a needle valve would be better and would require less torque from the servo.   Unfortunately I think for multiple turns on a needle valve, the gearing between it and the servo (typically 180 deg. range?) would result in a further loss of torque.

Setit, thank you too!  I have a few UDC 1000's laying around and will give your setup a go, hopefully next time I smoke.  It was 80 deg today here in NC, a record day and would have been perfect for a butt!  I guess for safety, even if I was to control the gas flow (and hence the size of the flame), I would need a pilot in case the flame extinguished due to being too low with a gust or something.


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## setitandforgetitsmoker (Feb 7, 2008)

trent you need a pilot light with thermocouple for sure. another thing is if you use the furnace gas valve 24 volt you either need a 24 v transformer or a pid output that is 24 volt i know alot of other ways to hook these pid units up to gas but this is probably if done properly the safest. good luck if you look at the pics that i have posted it will show you the location of my pilot and thermocouple location. also make sure to use a standing pilot propane valve not a milivolt valve with a thermopile. good luck if you do this just be safe.


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## geek with fire (Feb 7, 2008)

Yea, I'm a charcoal guy, so when I ball valves, it's to control air flow.  From what I've read here, your probably right about needing a needle valve for gas.  In any event, I've been playing with the stepper motor and encoder to control a valve.  The motor what whatever size you need.  The encoder tells the computer where the motor position/valve position is.


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