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Wood Gun Hi and Low Temps

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by CTFIRE, Jan 30, 2013.

  1. CTFIRE

    CTFIRE Member

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    Fellow WG owners. So the factory setting for low temp shut off is 140 and the boiler settings for operations are 150 on the low and 180 on the high. A couple times I have had the fire burn completely through the supply, boiler temp is way down and the fan is running for no reason. So I try and use the low temp toggle. Downside is that on a couple times over night the temp must have gotten to 140 and the fan shuts off the unit. Trying to decide which is worse the extra electricity cost or the lack of re-ignition. Keeping in mind I am only 10 weeks into this so I know I still have alot to learn. Has any adjusted the aquastats? I am thinking the 140 low shut off and 150 low temp are too close together. Not sure I can readjust the low temp, but was thinking of bumping the low to 160 or so. Thoughts?

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  2. topoftheriver

    topoftheriver Member

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    I don't think it makes that much of a difference. I like the 160 mark because you are getting better heat. The cost of electricity shouldn't be a factor. IMHO You may have to play with it until you find the area that is right for you.
  3. avc8130

    avc8130 Minister of Fire

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    You want the Wood Gun to run at a set point of ~180-185 with a differential of ~15-20.

    This will keep the boiler away from the low temp cutoff while it rekindles unless you are really out of wood or the fire is truly out.

    ac
  4. Fred61

    Fred61 Minister of Fire

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    That's the only way I was able to make it work. I think the reason they like to see the low temperature shutoff setting close to the lower setpoint is that the unit will pump less heat out of the boiler and up the stack before it shuts down. These units move alot of air and will cool rapidly if combustion fan is running, especially if your supply air is being ducted from outside as mine was.
  5. infinitymike

    infinitymike Minister of Fire

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    Now I'm confused.

    I have the operating limit stat on the right side of the back wall set to 190 with a differential of 10
    I have the low operating limit on the left side of the back wall set to 140
    I have the dual aqua stat on the top left near the front. The high limit is at 210 and the low is at 150
    I have the timer set with 2 pins every 2 hours and haven't lost a fire since I set them like that.(which was a couple months ago)

    I had them Set at 180 and 160 on the back and 190 and 160 on the dual. With no timer and lost fires all the time.
    I made the switch and didn't lose as many. Then added the timer and haven't lost any.

    I feel that if the WG can run just a little longer before the low temp shut off kicks in,
    it has a better chance of relighting. Or should I say it gives the "gremlins" more time to relight the fire!

    Let me know if there is another way to set it and I will try it out.
  6. avc8130

    avc8130 Minister of Fire

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    I checked my boiler last night because I was curious and this is what I found:

    Control Aquastat:
    190F w/ 25F differential. That is, on at 165F off at 190F.

    Dual Aquastat:
    High: 200F
    Low: 150F
    I believe there is a fixed 10F differential on this. SO...once the boiler temp clears the LOW (150F) it actually has to drop to 140F before it will kick off.

    Mike,
    What does your 3rd aquastat do? Is it for oil backup? Circulator control?

    ac
  7. infinitymike

    infinitymike Minister of Fire

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    My third aqua stat controls the oil back up. When the WG hits 140* it will switch to oil.

    I just went out and changed the differential on the operating limit to 20. It was actually set at 5 which now explains why it would kick back on so quickly. That also explains the "explosions"
  8. CTFIRE

    CTFIRE Member

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    Ok. I am a little lost. There are two honeywell aquas on the back and I am assuming the box on the top is the third. Not sure what they should be set at or what to change. Can someone do an aquastat for dummies cliff notes
  9. infinitymike

    infinitymike Minister of Fire

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    Do you have a separate burner for back up?
    And do you have the low temp shut off control?
  10. avc8130

    avc8130 Minister of Fire

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    I can...but I need to know what model WG you have and what options you ordered.

    Theory of operation is very simple, I just need to know what players are in the game.

    ac
  11. CTFIRE

    CTFIRE Member

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    I have the E140 and it was bought last year. New control model. Oil back up and there is a low temp toggle. Haven't hooked the oil up to the burner yet though. Not sure how to adjust the two on the rear top of the unit. There is a aquasat box on the top. That has some dials.
  12. avc8130

    avc8130 Minister of Fire

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    Ok, real simple.

    Top of the unit:
    2 dials
    1. High Limit, set this to the point you want the entire boiler system to STOP working in an "emergency" over temp situation (200-210F)
    2. Low Limit, set this to the point you want the fan to stop and the damper to close when the boiler is incapable of meeting the heating load (no wood/out fire, suggest ~150F)

    Back of the unit:
    2 aquastats
    1. Labeled "Operating" I think, set the lower dial visible through the window to the point you want the boiler to run the fan with the damper open until (180-190F). There is an upper dial, this is the "differential". Set this to the amount of degrees you want the boiler to drop before starting back up the fan and opening the damper (10-25F).
    2. Labeled "Burner" I think. Controls the oil burner switchover. Set this to the point you want the oil burner to kick on (140F)

    Hope this helps. This is all covered in your manual, but I understand it is easier when people with actual experience explain it.

    ac
  13. CTFIRE

    CTFIRE Member

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    Thanks AC. It is helpful for real world experience in that I accepted the factory settings. Wanted to get a little input from others as to the pros and cons of adjusting it
  14. infinitymike

    infinitymike Minister of Fire

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    I have mine set exactly like AC just stated.
    It works real well. I also have the timer set with two pins every two hours.
    It keeps the "gremlins" awake to relight the fire. I haven't lost one yet.

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