Digital temp and propane conversion

Discussion in 'Propane Smokers' started by mw-smoke, Jan 26, 2014.

  1. mw-smoke

    mw-smoke Fire Starter

    Heya folks - first time poster here and I need some help.

    I started another project and this time it's converting a vertical smoker to propane. Everything I've done up to this point has been coal and wood.

    I've been doing lots of reading but mostly I've been having to piece through threads and I'm just not sure that I'm doing things right.

    The goal is to attach the Bradley smoke generator to the vertical box.

    Temperature controls would be handled with a AGPtek universal digital PID temperature control.

    And gas control would be handled with a Honeywell VR8200A2132.

    Any advice on this setup?
     
    Last edited: Jan 26, 2014
  2. flash

    flash Smoking Guru OTBS Member

    I converted an old Great Outdoor Smokey Mountain Charcoal smoker


    These are much heavier and better made than the Propane models that GOSM. I finally decided to purchase a single burner propane plate and fed it thru the side vent and have it rested at the bottom of smoker.


    I don't use the pan with sand anymore, just rest the can holding wood and charcoal right on the burner. I did need to replace the regulator with a 10 psi model from a turkey fryer. Now I can get over 300º in this conversion.
     
  3. mw-smoke

    mw-smoke Fire Starter

    Hiya Flash - that's really nice looking! 

    Was the sand for holding in the heat? Did you add any water to the sand?
     
  4. flash

    flash Smoking Guru OTBS Member

     No, I had the idea that the wood may catch fire too quick if I rested the can down on the burner directly, so used the plate and added dampen sand as a buffer. Really all I had to do was close off the vents more and that stopped the wood from catching fire.

    As to the water pan, it is still used and I use either Playbox Sand or Water depending on conditions.
     
    Last edited: Jan 26, 2014
  5. wolfman1955

    wolfman1955 Master of the Pit

    Good mornin mw-smoke. I may be wrong but it apears that the valve you have listed is not a control valve to adjust your heat, but a safety shut off valve.
    If the pilot light goes out on a furnace or hot water tank the safety valve closes to stop all gas to the burner.
     
  6. wolfman1955

    wolfman1955 Master of the Pit

    I also looked at the PID controller in your post and here are the spec's for it:

    Compare Price and Reviews of AGPtek® Universal Digital PID Temperature Controller RNR Control Out Dual display For Fahrenheit(F) and Celsius(C).

    Specifications
    Display: Dual display for Fahrenheit(F) and Celsius(C)
    Range: -1999 to 9999 (depends on the input signal)

    Main output: Relay,Normal open, AC 250V/3A DC 30V/3A COS¦Õ =1

    PID cooling/heating control( can choose normal alarm output by software)
    Alarm Output: 1 RELAY: capacity AC 250V/3A DC 30V/3A
    7 different Dual Output combinations with:
    Accuracy: 0.2%
    Input: Thermo Resistor: PT100, Cu50
    Thermocouple: J,S,K,E,Wre3 ~ Wre25
    Dimension: DIN: 1/16 (48mmX48mmX80mm)
    Weight: about 150g
    Individually programmable PID control parameters.
    P, I, d, controlling period, digital filter coefficient, and more¡­ (for control theory experts only)

    SSR control ready to connect external Solid State Relay to handle High current. Applications.


    This is basicly an on/off controller that people are using for controlling tempetures in electric smokers.
    I own a Smoke Hollow Pro 44" gasser and have researched changing it over to PID control, I have not found a cost effective way to do that.
    Maybe someone on here has and would like to give us some more insight as to this mod.
     
  7. smokenado

    smokenado Smoke Blower

    I converted this old New Braunsfel to propane using Turkey Fryer burner but like you I'm trying to find a PID controller and valve to work together to control the temperature.
     
  8. wolfman1955

    wolfman1955 Master of the Pit

    Good mornin smoke, I work as an Instrument Tech. I deal with temperature and pressure control daily, mostly calibration of the instruments involved in these control loops. The problem with controling the temperature in a gasser with PID is that you have to have an anilog output PID controler going to an anilog control valve. Neither of witch are cheap. You would also have to have some sort of safety shut off incase the flame failed.
    I have read where people have converted propane kitchen oven controls over to there gas smoker, but they are not true PID control they are on/off with safety shut off. I supose this would work ok if like your kitchen oven your smoker was very well insulated to eliminate constant temperature swings and you had new enough equipment so that you would have electronic ignition for your burner. I don't think you could keep the old pilot light type, pilot burning outside in the wind.
     
  9. smokenado

    smokenado Smoke Blower

    Thanks for the info I actually have an analog controller left over from a previous project that has a ton of parameters that can be set. I was thinking that an actuated ball valve could be pulsed by the controller using the thermocouple as the PV as long as it was a 4-20mA probe but I need to locate an actuated ball valve that can be used for gas.
     
  10. wolfman1955

    wolfman1955 Master of the Pit

    You may want to go with what is called a V-PORT ball valve, They are capablbe of alot finer adjustment that would be needed for control of gas.
     
  11. mw-smoke

    mw-smoke Fire Starter

    Heya guys, I didn't know I had any replies on here until I came back to give an update.

    Well, after reading ya'lls advice, I'm hoping that I didn't dig myself into a hole.

    I got the parts put together and here is what things are looking like now:


     
  12. mw-smoke

    mw-smoke Fire Starter

    And the inside:

    Just the controller valve and burner:
     
  13. mw-smoke

    mw-smoke Fire Starter

    And the PID:


    Only problem so far is that I'm not sure how to setup the PID. The temperature readings are correct.

    I noticed that depending on how quickly the temperature drops, the PID will switch the relay on and off.

    It has an auto-set feature on it. When it's turned on, push a button, and it will ready how quickly it heats up and cools down, then adjusts itself to switch the relay on and off.

    But the only problem is that I'm lot seeing any voltage coming from the leads for the relay. I have the voltmeter hooked up, but nothing shows up even though I can hear the relay click on and off.

    So I have to figure how how to get that going. Then attach it to the valve controller and see if it switches on and off correctly.
     
  14. wolfman1955

    wolfman1955 Master of the Pit

    Mornin mw-smoke, I did a little research on your components and this is what I found:
    From the honeywell site:


    VR8200A2132/U
    24 Vac, Standard Opening, Standing Pilot Gas Valve with 1/2 in. x 1/2 in. inlet\outlet


    Find Equivalent or Replacement Products.






    Product InfoLiteratureAccessories & Replacement PartsOverview
    Gas valves for use in 24 Vac, gas-fired, standing pilot appliances with capacities from 20 to 200 cfh.

    Features

    •Gas valves include manual valve, two automatic operators, servo pressure regulator and pilot adjustment.
    •Compact size.
    •Provide two automatic valves.
    •Solenoid-operated first automatic valve opens on thermostat call for heat; closes when call for heat ends.
    •Diaphragm-operated second automatic valve opens under control of regulator; closes if gas or power supply is interrupted.
    •Meet codes requiring dual safety shutoff.
    •Natural to LP and LP to Natural conversion kits available for standard and slow opening gas valves.
    •LITE-RITE (OFF-PILOT-ON) lighting sequence.
    •All adjustments, wiring connections and pilot outlet are accessible from top of control.
    •Adjustable servo regulator effectively maintains almost constant gas output pressure under wide fluctuations in gas supply pressure.
    •Compatible with ECO connector.

    From this I interpret you need 24Vac to open the main gas suply from this valve to your burner. From your picture I believe you will need to move the pilot light assembly so the burner is not between the pilot flame and the pilot flame capillary sensor.

    From what i could find on your controller:

    Display: Dual display for Fahrenheit (F) and Celsius (C)
    •Range: -1999 to 9999 (depends on the input signal)
    •Main Output: Relay,Normal open, AC 250V/3A DC 30V/3A COSφ=1
    • PID cooling/heating control( can choose normal alarm output by software)
    •Alarm Output: 1 RELAY: capacity AC 250V/3A DC 30V/3A
    • 7 different Dual Output combinations with: high / low / high deviation / low deviation /interval / out of interval / breakage alarm
    •Accuracy: 0.3%
    •Input: Thermo Resistor: PT100, Cu50
    •Thermocouple: J,S,K,E,Wre3 ~ Wre25
    •Dimension: 1/16 (48mmX48mmX80mm)
    •Weight: about 150g
    •Individually programmable PID control parameters.
    P, I, d, controlling period, digital filter coefficient, and more… (for control theory experts only)
    •SSR control ready to connect
    external Solid State Relay to handle High current. Applications.
    •Compact design:
    DIN 1/16, great form-factor to be included/build-in to your product.

    If you look at the Main Output it is a relay it is a Normal open relay{a relay is nothing more than a switch}. I am very sure that this controller does not suply power to this relay and that it will require external power suplied to terminal 3 and out terminal 4.

    That being said your control valve operates on 24Vac you are going to need a 120Vac to 24Vac stepdown transformer. I saw one on amazon for $25 but you should be able to get one localy at any HVAC parts suply. You would suply 120Vac to the transformer and then run one side of the transformer out to terminal 3 then terminal 4 would wire to your gas valve the other lead from the transformer would wire straight to the gas valve.

    .
     
  15. wolfman1955

    wolfman1955 Master of the Pit

    Just thought of someting else!! I hope you dont run into a problem with the wind blowing out the pilot light! You might have to come up with some kind of sheilding to keep the wind away from your burner assembly and still have enough oxygen for combustion. Just a thought! You can always try it out and add the shielding later if needed.
     
  16. mw-smoke

    mw-smoke Fire Starter

    Thanks so much Wolfman!

    I need to go cancel some parts ordering real quick.

    I thought for sure it'd be a DC and not an AC, so I ordered a SSR for DC and a 110v AC -> 24V DC in-line adapter. 
     
  17. wolfman1955

    wolfman1955 Master of the Pit

    Had another thought! You need to have your original pressure regulator between your gas tank and your new gas valve!!! It looks like you just unhooked the burner end of your suply hose from the burner and hooked it up to your gas valve. That is the corect way. Just wanted to make sure gas is still regulated!!
     
  18. mw-smoke

    mw-smoke Fire Starter

    There is a pressure regulator on the bottle.

    I thought about putting in an extra pressure valve after the controller to fine tune it.

    I just have to find one that will fit, and I couldn't find one at the local hardware stores.
     
  19. wolfman1955

    wolfman1955 Master of the Pit

    mw-smoke evadently this mod has me hooked cause i just keep thinking about it! I am not sure that your pilot light is going to work! If the pilot light assembly you bought is for natural gas then the orifice in it will be to large for LP, and will need replaced. If it is for natural gas you could probably find a replacement at your local HVAC parts suply.
     
  20. wolfman1955

    wolfman1955 Master of the Pit

    I dont think you need another pressure regulator. You might install a needle valve to regulate the gas flow because the way it is now you are running at full flow. I think you should be able to get a needle valve at lowes or menards or home depot.
     

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