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Propane to NG conversion

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doc holliday

doc holliday

Newbie
Original poster
Dec 30, 2009
4
11
I just joined, introduced myself and have spent some time pokin' around. So much to learn and so little time. After a month of searching for a natural gas smoker without any luck, Ms. Doc bought me Landmann LP gas smoker from Bass Pro Shop for Christmas. I want to convert it to NG I've read some of the internet sites about pressure, inches of water, orifice size, numbered drill bits, etc but the more I read the more confused I get. Was wondering if anyone here has actually done it with a Landmann 18,000 BTU smoker or something similar and cout help me out with some simple directions. I'd be mighty oblidged.
Doc
 
Well Doc this may or may not help you out. I have not converted landmann, but i can give you some info on how to go abought it. I have seen natural gas conversion units at my local LOWES, they run around $34.00. I have never used 1 nor know any 1 that has. I have helped a friend of mine convert his LP (propane) grill to natural gas, and its very simple to do and costs a whole lot less then $34.00. First thing you need to do is get rid of the propane regulator, you dont need 1 on natural as its regulated at the meter. Next step is to drill out your orface. If you dont know your gas presser call your gas company and ask them for presser in inches of water column, then use the cart on this web page for the drill size. http://www.bacharach-training.com/orifice_chart.htm
Example you have a 18000 btu burner, and a natural gas presser of 7" water column you would drill out your orface to a size 50 thats a #50 drill bit. As you can see in the chart a size 50 orface is only 17594 BTU's. When I was helping my friend out i asked another friend who is a heating and air guy, abought this and he told me to start with a BTU that was close but under , as i could allways go up 1 size but not back down. Hope this helps you out.
 
Sounds like SPRKY has it about right.

I have not converted a Landman or anything to NG, it has always been NG to LP with some other stuff though

A plumbing supply house, RV dealer or LP supplier may have orifices that will swap out with what you have depending if your unit is actually designed with a removable/replaceable orifice

There is the issue of the plumbing as well, that is the piping or hose to your grill. Quick disconnect hoses like alot of restraunt equipment is hooked up with are high dollar as are their fittings. Flexible corrigated/ribbed tubing is easy but not as freindly as the higher priced hoses for moving the grill for cleaning and such. Also keep in mind to use gas pipe or black pipe and not galvanized pipe when you use hard pipe
 
Thanks for the help guys. Now that the weather has finally gotten a little better and Lowes has gotten their NG BBQ parts in, I'm finally getting around to actually converting my LP smoker to NG. Adding a new NG service was the eazy part, took about six minutes to splice in a new valve on the NG line to my BBQ. Things quickly went down hill from there. Based on the 13,500 BTU rating on the smoker (from the manufacturer), 7" water column pressure for NG, the orifice size per the chart should be 1/16" max. Imagine my surprise when I discovered that the orifices for LP use are already somewhere between 7/64" and 1/8". Based on the chart for LP, this equates to 83,603 BTU, not 13,500. Per the chart, just leaving the burner as is and connecting NG at 7" water column pressure will give me about 14,000 BTU.

Now the question, Am I totally missiing the boat?
Thanks, Doc
 
I buit a manonometer and the NG pressue at the smoker is exactly 7" WC. I finally said what the heck and fired it up. Seems to work fine.

Doc
 
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So, did just running a natural gas hose into the propane connection on the Landmann was all it took?

How is this working?

Do you think that drilling the orifice would make it work better?  Does it reach a good high temp?  How high?  How does it work on low, and how low does it smoke reliably?

Anyone else have any recommendations about this?

Thanks in advance
 
Last edited:
Don't know if you are still working on this....  I changed a propane grill from propane to ng by... going to bbq Galore.. they had blank jets and charts that the guy used to tell me the exact size for the ng orfice.. then I went to Ace Hardware to get the tiny drill bits.. the whole process took a couple of hours including driving around to get the jets and bits...it worked fine and used it for over 4 years... By just hooking up the line to ng only and not changing the jet or at least the orfice size, it will not put out enough BTU's
 
Most natural gas equipment is set from the factory to run at 3.5" WC That' the common pressure after the meter and regulator "most" gas companies use....NG orfice sizes are usually a LOT bigger because 1. Propane pressure is 11" WC and 2. Propane burns hotter than NG. That being said, if it works, it works. It might not work as well in cold weather but you can always drill it a bit bigger. One thing about going bigger is if you go too big its harder to shrink the hole. lol.... If it seems to be between two drill sizes it's probably a number drill size. BTW I did finally find my drill charts.
icon_wink.gif


 I converted a 3 burner gas grill once and a 3/8 copper line wouldn't supply enough NG to run it. Had to run a 1/2" black iron pipe.
 
I have natural gas for my weber and turkryfryer/beer kettle and would like to add a NG smoker, what are your ideas or experienc?  Thanks in advance
 
Looking to convert my 44" Smoke Hollow to NG and have a question:

Why can't I run NG using the propane orifices?  Will that not reduce the BTUs and help with the bottom-end temps?  Or will the gas flow be so low it won't light/stay lit?
 
A couple of things to think about.  The NG industry is heavily regulated, and there can be safety consequences when doing home owner modifications.  On a side note, I have been out of the business for a few years, and these regulations can change on an almost daily basis. 

What regulations is your local area following, National Fuel Gas Codes, or International Fuel Gas Codes?  What does your smoker manufacturer say about making this conversion, did you ask? 

The last time I dealt with this, the code said that you could make a conversion with the manufacturer's permission and guidelines.  Every manufacturer of "grills" that we contacted told us that there were no authorized conversion allowed.

When hooking up to the gas line, you will probably be required to hook up using a flexible hose, and quick connect fitting, along with a shut off valve.  The hose cannot be one of those stainless steel ones for stoves and dryers.

Now, having gone through that, people make these conversions every day, and few have any problems.
 
Yeah, it was a pretty short putt to figure out that NG won't light with the LP orifice.  On to getting the right orifice.
 
Called Smoke Hollow which said their smokers haven't been tested for NG so they don't sell NG orifices.  The lady suggested I contact a plumber to make the conversion for me.  So now I've been to two grill stores, the local gas supplier, a plumbing supply house and several hardware stores.  When I explain what I'm looking for, they all act as if I've asked for kiddie porn or weapons grade plutonium.  They literally won't touch the orifices I have to tell me what thread size they are.

Anyway, anyone have a current source for generic, blank orifices I can drill myself?  I don't want to start monkeying with my smoker until I know I have a Plan B and can at least go back to square one if I mess up.

Question:  when you guys speak of numbered drill bits, are those wire sizes?  Thousands of an inch? Being a carpenter not a machinist I'm not familiar with stuff smaller that a 16th.
 
2Cub, Open the link I posted.....  On the left is the drill size.... next column is the orifice size in thousand's of an inch.... next columns are BTU's at given pressures for Natural gas and finally propane.....   Check the orifice size in your smoker.... knowing the pressure of the regulator, you can instantly convert your orifice size to what is needed to operate on natural gas.....   for the cost of a plumber, you can purchase a drill bit set and have spare change.... You will need a regulator that can be adjusted down around 4" water or so from the 7-11" propane needs....  If you are happy with the temp range of your smoker, copy the nat. gas numbers given...... If your smoker runs too hot, drill the hole smaller than recommended for the same BTU's......   Use the drill set to measure your existing orifice for starters.... go up in sizes slowly.... remember to adjust the air for a clean blue flame while testing and be sure to clean the burner tube to rid it of any spiders or web type stuff so you don't have a false test burn......  

Dave
 
I'm definitely a newbie among experts here on this forum.  I'm converting a Smoke Hollow 4 in 1 to NG and want to make sure I've got everything correct from y'alls discussion.  

From what I've read, these should be the steps to convert and connect my grill to the quick connect NG line on the porch.  Please correct or confirm my checklist:

1) buy a male quick connect piece

2) attach quick connect to black rubber hose

3) put a shut off valve in the hose line

4) attach the hose to the gas supply on the grill

5) check my water column measurement coming from my NG meter

6) use chart provided by DaveOmak to find the orifice size which gets my burners just under the BTU rating.

7) buy correct size drill bit and drill out orifices.

8) double check connections and get grilling

Does that look like it'll get it done?  Any other tips?  Like using Teflon tape, or anything else.  Thanks in advance
 
How did the process go for you? Can you post some pictures or video of the process if you have one.
 
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