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convert Nat gas to prop

penfrydd
penfrydd Member Posts: 1
I recently bought a brand new gas heater at an auction for a great price, only to find that on the back it's labelled "natural gas only".



I thought a simple change of nozzles was all that's required, but the manual for this one says it can't be converted. What gives?

Comments

  • icesailor
    icesailor Member Posts: 7,265
    Labels:

    Usually, if it says it can't be converted, it can't be practically converted. Unless you change a bunch of expensive parts.
  • Tim McElwain
    Tim McElwain Member Posts: 4,451
    When an appliance states

    for a certain gas only then it is not to be converted and if you choose to do so you are in danger of excessive carbon monoxide issues. DO NOT CONVERT IT!



    It has to do with burner design, chamber size and internal venting issues. It also as Ice stated can be very costly as you literally would almost have to completely redesign it with all new parts.
  • icesailor
    icesailor Member Posts: 7,265
    Converting gas appliances:

    Tim can tell me I'm full of it but:

    No one ever told me this. It is my personal observation of what he said and why it can't be done.

    I have converted a lot of gas appliances from NG to LPG because most all of the consumer driven gas appliances are designed and sold as Nat. Gas appliances. And where O worked, there will never be Nat. Gas available. The majority of gas appliances like stoves and dryers are installed as Nat. Gas. LPG is a much smaller part of the industry. So, the burners and accessories are designed for NG. LPG is just another afterthought. They now use some form of "Shot-Gun" type burner with little if any adjustment for air-fuel mixtures. Whatever orifice is used on say a 5,000 BTU cook top, uses an appropriate spud/orifice to supply the proper amount of undiluted gas through the venture/mixing space and into the burner that is designed for a set amount of air/fuel to burn. At the NG pressure range expected. Which can be wide.

    With LPG, it takes a much smaller orifice because the pressure is higher and the gas has more BTU's. To try to get an equal amount of properly mixed gas to give you a air/fuel ratio without copious amounts of CO coming off the burners with LPG is a seriously difficult task.

    If you get a stove that needs to be converted, notice that the NG BTU rating will always be higher than with LPG. Because they can't mix it properly so they find a sweet spot" to give them the best and safest output.

    A year or so ago, I installed two LPG fireplace logs that are approved for open flue fireplaces with the dampers removed. They can NOT be converted. You order them for Nat. Gas or LPG. These are the models that don't smoke and use a Bunsen flame between the fake logs. Two years prior to that, I did the kitchen over. I converted and installed a brand new well recognized brand of stove. Gas cooktops and electric bottoms. To properly size the gas piping, I needed to know the output of the 5 burners on the top if all were running at the same time. Our inspector might want to see the figures. There were no ratings for LPG, only Nat. Gas. What I went through. Tech support was clueless as to what I was talking about. They told me that I didn't need to use the supplied spuds.  The manufacturer supplied the spuds. That wasn't the issue. The stove was convertible, the logs were not. When I was done with the installation of the logs and I fired them off, I stuck my Insight analyzer in the exhaust stream. After 20 minutes of steady running, the CO level never went above 10 PPM. I tried the stove. The worst burner was 95 PPM. The normal was 75+ PPM, CO. And this is an approved stove.

    Massachusetts requires hard wired CO detectors on each floor. This job was compliant.
  • LPGasman
    LPGasman Member Posts: 18
    Manufacturers .......

    Well I had a nice rant all typed up about Manufacturers and their conversion methods but when I solved the math problem and clicked submit it took me to the log in page and the rant was lost to Cyber World. In a nutshell these companies need to get their feces together and work "with" the LP gas techs instead of against us. I propose we all refuse to do the conversions till they get it together including supply tech support they are a joke.
  • icesailor
    icesailor Member Posts: 7,265
    Wall Street Pirate Fleet:

    I can see that you just don't understand how the business model works. If all you see is LP, you have no idea how small the LPG market is compared to Nat. Gas. Most new appliances are bought at big box discounters at the cheapest price available by homeowners, decorators or contractors. If you sell gas ranges, like in Palm Beach County, Florida, most gas ranges will be LP. If you bought a range in Boston, they'd mostly be Nat. Gas. Many sales people and customers think that a "Conversion" is something that happens in a football game after a team scores a touchdown.

    Its cheaper for the manufacturer to build stoves set up for Nat Gas than for the few used for LPG. Its cheaper and more profitable to have the purchaser pay YOU to convert it than to confuse the non-English speaking workers on the assembly line. They either have spuds you screw in tightly, or they give you a set of color coded orifices, mounted under the stove so you have to hunt for them. If you don't convert it first for LP, you usually know immediately because the thingy inside the regulator isn't flipped over and the orifices are too big. When the spark starts and the gas lights, most know immediately that something is wrong when they see a 1' yellow flame shooting out of the burner. Ovens are another issue. "Out of sight, out of mind". Unless someone is overcome by CO. And if someone thinks that's normal (DIY Homeowners who don't speak English and don't read French or Spanish) they become alarmed when the bottom of the pots turn black. They blame the junk stove and call the seller to complain. You get a call for service. You get paid (hopefully). Makes work for you. Wall Street gets to keep the profits and everyone is happy.

    What could be better?
  • Tim McElwain
    Tim McElwain Member Posts: 4,451
    to clarify

    Converting gas appliances:

    Tim can tell me I'm full of it but:

    No one ever told me this. It is my personal observation of what he said and why it can't be done.

    I have converted a lot of gas appliances from NG to LPG because most all of the consumer driven gas appliances are designed and sold as Nat. Gas appliances. YOU CAN ORDER APPLIANCES SET UP FOR LP THAT DO NOT NEED CONVERTED.



     And where O worked, there will never be Nat. Gas available. YOU NEVER KNOW YOU COULD GET LNG OR CNG SOMEDAY.





     The majority of gas appliances like stoves and dryers are installed as Nat. Gas. LPG is a much smaller part of the industry. So, the burners and accessories are designed for NG. THAT IS NOT CORRECT I HAVE VISITED MANY OF THE BURNER MANUFACTURERS WHO MAKE BURNERS AND HAVE BEEN ADJUSTING GAS BURNERS FOR MANY YEARS. MOST OF THE BURNERS TODAY FOR EXAMPLE MAY NOT COME WITH AN AIR SHUTTER. THAT IS A BURNER WHICH IS COMPATIBLE WITH BOTH LP AND NAT GAS BY DESIGN.



     LPG is just another afterthought. They now use some form of "Shot-Gun" type burner with little if any adjustment for air-fuel mixtures. THERE ARE WAYS TO ADJUST THOSE BURNERS WHICH WE TEACH IN OUR CLASSES.



     Whatever orifice is used on say a 5,000 BTU cook top MOST COOK-TOPS ARE 10,000 TO 12,000 BTUS' AND USE COAXIAL ORIFICES ALSO CALLED UNIVERSAL ORIFICES WHICH CAN BE SCREWED ALL THE WAY DOWN ON THE SPUD FOR LP AND ALL THE WAY OUT FOR NATURAL. THERE IS ALSO USUALLY A CONVERTIBLE REGULATOR WHICH CAN BE USED FOR BOTH LP AND NATURAL GAS. THE ONLY EXCEPTION TO THE COAXIAL SPUDS ARE WAIST HIGH BROILERS AND THOSE HAVE AN ORIFICE SHIPPED WITH THE STOVE UNDER THE COOK TOP IN A SPECIAL SPOT. THE OVEN SPUDS ARE ALSO COAXIAL., uses an appropriate spud/orifice to supply the proper amount of undiluted gas through the venture/mixing space and into the burner that is designed for a set amount of air/fuel to burn. At the NG pressure range expected. Which can be wide. THE CONVERTIBLE REGULATORS GIVE 6" W.C. ON NATURAL GAS AND 10 : W.C. ON LP AND THOSE PRESSURES ARE FIXED.

    With LPG, it takes a much smaller orifice because the pressure is higher and the gas has more BTU's. To try to get an equal amount of properly mixed gas to give you a air/fuel ratio without copious amounts of CO coming off the burners with LPG is a seriously difficult task. NOT THAT DIFFICULT WHEN YOU KNOW WHAT YOU ARE DOING.

    THE MOST LIKELY APPLIANCE TO BE SET UP FOR A PARTICULAR GAS AND LABELED NOT CONVERTIBLE IS ON WATER HEATERS AND THAT IS DUE TO THE DESIGN OF THE WATER HEATERS AND THERE SUSCEPTIBILITY TO MAKING HIGH LEVELS OF CO.



    If you get a stove that needs to be converted, notice that the NG BTU rating will always be higher than with LPG. Because they can't mix it properly so they find a sweet spot" to give them the best and safest output.

    A year or so ago, I installed two LPG fireplace logs that are approved for open flue fireplaces with the dampers removed. They can NOT be converted. You order them for Nat. Gas or LPG. These are the models that don't smoke and use a Bunsen flame between the fake logs. Two years prior to that, I did the kitchen over. I converted and installed a brand new well recognized brand of stove. Gas cook-tops and electric bottoms. To properly size the gas piping, I needed to know the output of the 5 burners on the top if all were running at the same time. Our inspector might want to see the figures. There were no ratings for LPG, only Nat. Gas. What I went through. Tech support was clueless as to what I was talking about. THAT IS BECAUSE THE INPUTS FOR NATURAL AND LP ARE THE SAME A BTU IS A BTU. IF YOU USE AN ACCURATE CALCULATOR TO SIZE ORIFICES THERE WILL BE NO PROBLEM MATCHING UP BTU TO BTU. THEN TUNING THE BURNERS USING A COMBUSTION ANALYZER WILL SOLVE ANY CO ISSUES. They told me that I didn't need to use the supplied spuds.  The manufacturer supplied the spuds. That wasn't the issue. The stove was convertible, the logs were not. When I was done with the installation of the logs and I fired them off, I stuck my Insight analyzer in the exhaust stream. After 20 minutes of steady running, the CO level never went above 10 PPM. I tried the stove. The worst burner was 95 PPM. The normal was 75+ PPM, CO. And this is an approved stove. THAT SHOULD NEVER BE SOMETHING IS DEFINITELY WRONG EITHER YOU NEED TRAINING OR SOMETHING IS DEFECTIVE.

    Massachusetts requires hard wired CO detectors on each floor. This job was compliant.
  • LPGasman
    LPGasman Member Posts: 18
    RE: Manufacturers

    I am all for making money, the point I was trying to make is that the manufacturers know that some of these units will be connected to propane, and they should go the extra mile to help the tech who is converting the unit. If I was manufacturing these products, I would do all I could to make sure the conversions are done correctly. Frigidaire for instance gives you a bag full of orifices, apparently one kit fits all, Kenmore on the other hand gave a kit all orifices needed punched thru a piece of cardboard that showed the location of each one. Don't get me started on the new dryers that you need to be a magician to just get into the parts you need to access, the instruction tell the conversion procedure but you are on you own opening the unit!
  • Tim McElwain
    Tim McElwain Member Posts: 4,451
    For Dryers

    with no access door to the burner the instructions for some dryers tell you to remove the back, remove the drum and install the new burner orifice. I have found on several dryers it is easier to turn the dryer over and take the bottom of usually 6 to 8 screws and you have direct access to the orifice in the burner.



    The reason the door was done away with was due to children opening the burner access door which did not shut off the drum and little fingers getting cut-off. That was the same reason many years ago a mechanical switch was placed on the access door to the drum.
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