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Thread: Oil to gas

  1. #14
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    oil to gas

    Quote Originally Posted by Poodle Head Mikey View Post
    I used to do them all the time. Gas gun to replace the oil gun. You will want to clean the boiler and the chimney VERY well. And technically I think the chimney has to be lined with stainless - check your local code on that one..

    PHM
    -------
    PHM, Thanks for that. Gives me more certainty that I will be doing the right thing for the customer. I have worked on many oil to gas guns on furnaces, but not one on a boiler. That is why I was asking.

    I will have to check with code and the liner.
    Can someone please explain to me -
    Why is there never enough time to do it right the first time, but plenty of time to do it twice?


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  2. #15
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    Quote Originally Posted by hvac69 View Post
    If the new gas burner is rated at 100k BTU what would be different than an oil burner rated at 100k? A lot of commercial boilers are dual fuel fired with no issues.
    condensation. gas is full of water and releases it during combustion. typical commercial boilers have larger passages and are made sturdier so it's not much of an issue. plus, you're going to have a MUCH larger flame pattern on a gas burner to equal the same btu content. Impingement, CO, sooting will result. Now, mix that with water... and it becomes a primordial pond of failure.

  3. #16
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    Quote Originally Posted by Poodle Head Mikey View Post
    Not one of these statements is accurate.

    PHM
    --------
    Quote Originally Posted by me
    additionally, oil has many more btus than gas. it's hotter, faster. that boiler will condense for a long time before it heats up appropriately on gas. It's going to make a mess and fail prematurely.
    Per equivalent unit - gas has far fewer BTUs than oil. see here, for example: http://www.exothink.com/Pages/btu.html

    This is not something Im pulling out of my butt. This is based on experience from following behind other companies who have converted oil to gas. To get the equivalent btus out of a gas burner it's going to be a bigger flame, or a smaller burner running longer.

  4. #17
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    If I were in your shoes, I would follow the advice in my first post. Call Carlin with the model number. If it's not in their OEM set-up guide, and they never put one in that boiler, I wouldn't do it.
    But if they have specs, meaning they have had success with it, that would be good enough for me to consider moving forward.
    Now some caveats, some pointed out by Marc:
    Make sure the boiler has protection with a modern aquastat that will shut off the circulator when the boiler temp is below 140 or the boiler has bypass piping with a mixing valve. This will allow the boiler to heat up quicker and get out of condensing mode quicker.
    Also, you will need to line the chimney.
    Keep in mind, and this is why I don't like to do this, power burner + chimney liner + boiler protection (aquastat/piping) is a pretty large investment, and may not save the homeowner any money (or may cost more).
    If their goal is switching to gas, a new modern, properly sized boiler will be the best way to go.

    But conversions can successfully be performed.
    If I do a job in 30 minutes it's because I spent 30 years learning how to do that in 30 minutes. You owe me for the years, not the minutes.

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  6. #18
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    1. "oil has many more btus than gas."

    100,000 BTU's produced by burning oil, or by burning gas is still . . . 100,000 BTU's <g>

    2. "(oil) is hotter, faster"

    The flame temperature for natural gas is about 3500 F. The flame temperature for # 2 fuel oil is about 2600 F.

    3. "that boiler will condense for a long time before it heats up appropriately on gas."

    Burning 100K BTU's worth of natural gas releases about one quart of water
    Burning 100K BTU's worth of # 2 fuel oil releases almost three quarts of water

    4. "It's going to make a mess and fail prematurely."

    There is no basis that I am aware of for this statement's support. I am always interested in learning new things - so maybe someone besides me can explain in detail why and how it is accurate? <g> I can leave you with a statement which I know to be true: (#4 above) has never once been my experience with oil-to-gas appliance conversions and I have had quite a bit of it. <g>

    PHM
    -------




    Quote Originally Posted by buttwheat View Post
    Really enlighten me
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  7. #19
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    Quote Originally Posted by Poodle Head Mikey View Post
    1. "oil has many more btus than gas."

    100,000 BTU's produced by burning oil, or by burning gas is still . . . 100,000 BTU's <g>

    2. "(oil) is hotter, faster"

    The flame temperature for natural gas is about 3500 F. The flame temperature for # 2 fuel oil is about 2600 F.

    3. "that boiler will condense for a long time before it heats up appropriately on gas."

    Burning 100K BTU's worth of natural gas releases about one quart of water
    Burning 100K BTU's worth of # 2 fuel oil releases almost three quarts of water

    4. "It's going to make a mess and fail prematurely."

    There is no basis that I am aware of for this statement's support. I am always interested in learning new things - so maybe someone besides me can explain in detail why and how it is accurate? <g> I can leave you with a statement which I know to be true: (#4 above) has never once been my experience with oil-to-gas appliance conversions and I have had quite a bit of it. <g>

    PHM
    -------
    2- https://en.wikipedia.org/wiki/Adiaba...me_temperature

    gas is cooler. in a properly atomized oil flame I know for a fact it gets hotter than the listed 3800+ degrees.

    3- http://www.ncoilheat.org/files/3614/...Manual2013.pdf

    it contains .05% by volume, water. the hotter temperature of oil causes the vapor to flash to steam more quickly and flow out with the flue gases, rather than condense inside the system

    1- the math works but the practical application rarely does. and it's because the fuel and the burner are very different. to get the same 100,000 btu from gas it's going to be more air, more fuel, and bigger flame. in a given sized combustion chamber that usually results in problems.

    4- given the data above, and from my experiences cleaning up after other companies, it's all true

  8. #20
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    OK.

    PHM
    ------



    Quote Originally Posted by HVAC_Marc View Post
    2- https://en.wikipedia.org/wiki/Adiaba...me_temperature

    gas is cooler. in a properly atomized oil flame I know for a fact it gets hotter than the listed 3800+ degrees.

    3- http://www.ncoilheat.org/files/3614/...Manual2013.pdf

    it contains .05% by volume, water. the hotter temperature of oil causes the vapor to flash to steam more quickly and flow out with the flue gases, rather than condense inside the system

    1- the math works but the practical application rarely does. and it's because the fuel and the burner are very different. to get the same 100,000 btu from gas it's going to be more air, more fuel, and bigger flame. in a given sized combustion chamber that usually results in problems.

    4- given the data above, and from my experiences cleaning up after other companies, it's all true
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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