Converting Member's Mark BBQ Grill from Propane to Natural Gas

A most excellent writeup on converting your Member's Mark Gas Grill from Propane to Natural Gas published here with permission from Daniel K. Schuster (aka dannos). Daniel was a wealth of information and support while I did my BBQ Grill conversion from Propane to Natural Gas and if this is too technical for 'ya, then check out my Grill Recipes! ;-)

Natural Gas Conversion

Back by popular demand.....

Just my luck, my post on the last thread was #100, and maxed it out, so I'm posting it again on this new thread, hoping to head off some common email questions.

I continue to receive numerous emails inquiring about how to convert this grill from LP to NG. I think people are having trouble finding my original post from a year ago.

This is kinda long, so if you're not interested in converting, don't bother continuing to read.

It's been converted for a year now, and I'm very satisfied with the results.

Actually converting the grill was the easiest part - about two hours. Running the NG line to the deck was the hardest and most expensive part. Since it takes so much more volume of NG to replace LP, the diameter sizes of the nozzles is not nearly as delicate/critical as it first appears. There is no standard SAE drill bit that will work good for the grill burners - too small or too big. Just get a numbered drill bit set. Other posters have also concluded that the following drill sizes seem to work pretty good, but check your gas pressure and use your own judgement. Once drilled out, you can't go back down in size without a lot of trouble. It only took about 15 minutes to remove/redrill/replace the nozzles.

Another common question: Why did I convert?
I converted because after I bought this grill, the amount of grilling I did virtually quadrupled. I make extensive use of the rotisserie too, which wasn't even a consideration when I bought it. I went from refilling the LP bottle 2 to 3 times/year to every 3 weeks. (I logged 4 hours on the rotisserie last weekend alone.) From what I can tell, the grill added about $5 to $8/month to my NG bill. The oven hasn't been used to roast/bake ANY meat since I bought the grill - not once, no bull.

Do I use the LP regulator after conversion?
No. The NG pressure should be regulated at the meter where it comes into the house. You connect the NG line directly to the manifold on the grill.

I'm using #49 or #50 for the main burners and it doesn't seem to get as hot as it used to. Can I open them up more?
Yes. Just keep opening them until you're satisfied with how quickly it heats up and how hot it gets.

Common question from both LP and NG users is: How fast should it heat up?
At 58 degrees outside temp, my grill heated up to a hood temp of 400+ in 10 minutes, with the grease on the cooking grates beginning to smoke. While mine is NG, it's still pretty close to what I had with LP, except it might be a little hotter after conversion to NG.

An update to drill sizes I evenutally used:
10k rotissorie #52 or 1/16" bit.
12k sideburner #51
18k mainburners #44

See my Tue, Apr 10, 01 at 12:25 post on:
Posted by: Dan ( on Tue, Apr 10, 01 at 12:25

Well, I successfully got my B&C grill converted to natural gas.
The short version:
My grill: Baker & Chefs, model number Y0005XC-1, with 3 18,000 BTU main burners, a 12,000 BTU side burner, and a 10,000 BTU infrared burner.

Factory settings: The 3 main burners had a #55 orifice, the side burner had a #59 orifice, and the infrared burner had a #61orifice.

Gas pressure: I measured 8" WC with no appliances on in the house and the grill off. I measured 6" WC gas pressure with the 3 main burner valves on high and the infrared burner valve on. I had to run about 30 feet of 1/2" black iron pipe, and that was reduce to 1/4" for a quick disconnect fitting, and then an additional 15 feet of 3/8" high pressure hose from the quick disconnect to the grill.

I ended up with a #47 for the main burner, #51 for the side burner, and #53 for the infrared burner.

Drilling the orifices out to the chart from made my grill run too cool. I believe the chart to be accurate, but there are other factors in play. Drilling the 3 main burners out with a #47 bit, 0.0785", (5/64", 0.78125, would virtually be the same) worked reasonably well for main burners, the side burner was drilled out with a #51 (.067) which turned out to be better than factory, and the infrared was drilled out with a #53 (.0595). I may go up one size for the main burners and infrared burner, but I'll have to use the grill for a while before I do that.

The infrared is a little cooler than factory, which is what I wanted. The next size up is 1/16" if the #53 turns out to be too cool, but I don't think it will be. On low, the main burners are so low that they'll probably blow out in moderately windy conditions. On high, the main burners are at least as hot has factory. For the side burner, the low setting is lower than factory, but on high, the flame is bigger than factory, almost to the point of being excessive, I definitely wouldn't use anything larger than 1/16" bit for the side burner or the infrared. I happen to like it this way, because I use the side burner for a butter/garlic sauce for basting, which requires very low heat.

The long version:
Like most people, I've never done this kind of conversion before, and I'm a little nervous about screwing up my new $600 grill, so I proceeded cautiously. This part may get a little long, because I'm an engineer by trade, and I can't help myself.

I didn't have a way to actually measure the gas pressure, so I called the gas company and asked them what my house pressure should be. The 1st time I called, they said it was 11" WC. I told them that couldn't be, because that's LP pressure. Then they retracted and said it was 9" WC, which isn't even on the chart. So, I called again, hoping to get someone else. This time they said it was 7" WC. I accepted this, thinking maybe they misread a 9 for a 7 on the 1st call.

I had received my 115 pc drill bit set from for $38, so I had the numbered bits called out in the chart. I drilled the orifices per the chart, #50 bit for the main burners, #53 bit for the side burner, and #54 for the infrared. Well, the infrared burner wouldn't stay lit, and the main burners looked like they were running at about 2/3 throttle. Well, this meant that either I didn't have 7" WC gas pressure, the chart was inaccurate, the gas line I ran out to the deck couldn't supply enough gas, there were other factors in play I hadn't considered yet, or a combination of all of these. 1st, I had to eliminate the question of gas pressure. I made a water column measure (also called a manometer, which I've used before in my job), to measure the gas pressure. I have since found a web site that shows how to construct a cheap, but effective water column measure. I've included it at the end of the post. I just happened to have some clear pvc hose left over from a home-made water from when I built my deck, and it fit perfectly over the side burner nozzle. With no burners on, I indeed had 8" WC gas pressure. With one burner on high, I had 7" WC. With all 3 main burners on high, and the infrared burner on, I had 6" WC. Even after drilling the orifices out wider, the pressure never dropped below 6" WC, so I know I didn't have a problem supplying enough gas to the grill. Since I have no way of measuring BTU output, I wasn't able to verify the accuracy of the orifice chart. However, I believe the chart to be accurate. It is simply stating that, under controlled conditions, 7" WC NG pressure will produce 18,000 BTU's with a #50 orifice. But the temperature of the valves and orifices change dramatically as the grill heats up, metal expands, and very small changes in conditions can produce big changes in BTU output. After all, from 3" WC to 7" WC, which is more than twice the pressure, the nozzle opening only changes from a #45 bit to a #50 bit, a change of only .012 inches. From a #50 bit to #47, which is what I changed to was only .006 inches. There's only .001 inch difference between a #59 and #60 bit. Chucking up a very small bit into my Makita and drilling a hole by hand probably has a tolerance of +/- .005 inches. The unknown factor that came into play, I believe are the valves themselves. They are designed for delivering LP, not NG. I believe NG is a much more dense gas, so that's why it runs at about 1/2 the pressure of LP. It also explains why, for a given equivalent nozzle diameter, the low setting is lower for NG than LP, almost to the point the burner goes out, but on the high setting, the flame is as hot, if not actually hotter, than LP. So, from what I've learned, the trick is to find a size such that on low, the burner doesn't go out, but on high, you don't have a meltdown in your grill. I also noticed that as the grill became very hot (400-450 degrees) the main burners weren't as high as they were when the grill was cold. I always thought this was due to the LP bottle frosting up, but now I think a lot of it has to do with the valves getting hot and metal expansion. At an outside temperature of 45 degrees, and a little wind, the grill quickly heated up to 400 (4 or 5 minutes), but struggled to get to 500 (about 10 minutes). These times and temperatures are very close to what I got with factory settings and LP, so I'm confident I'm about as close as I can get.

Accessing the orifice nozzles:
For the side and 3 main burners, simply remove the burners, and unscrew the nozzles - a 10 minute job.

For the infrared burner, I was able to remove one of the screws holding spider screen in place from underneath the cast iron housing at the back of the grill, carefully bend the screen out of my way, and use a small wrench to unscrew the nozzle. I have small hands, so others may have to remove the hood, the heat deflector plate covering the cast iron housing for the infrared burner, and the remove both the top and bottom screws to the spider screen and remove the screen entirely for easier access.

How to construct a water column measure (manometer):

Where I bought the numbered drill bit set ($38 shipped):

Orifice size/BTU drill chart:

Happy grilling.....

RE: Member's Mark Gas Grill - Part 2 (continued discussion)


Mine is the older model, but this is how mine came out:

Main burners:
After I took the 3 main burners out, I could sneak a wrench up from below, and loosen the nozzle. Then I could reach in with my fingers from the burner compartment and spin them out.

Infrared burner:
You can take it all apart, or if you have small hands like me and it's like my grill...
Take the spider screen off, use a needlenoze pliers, reach up and loosen the nozzle. Now you, or someone else with small hands, reach up and spin the nozzle off, using the index finger from each hand. Not real easy, but it can be done.