Natural Gas & Propane Stoves

All O’Keefe & Merritt stoves I’ve encountered are configured to be fueled by natural gas (NG); sometimes called methane.

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People online write about converting their gas stoves from NG to liquid propane (LP), primarily because the stove has been setup in a location where it’s no longer possible to connect the stove to the NG supply system.

NG is not as potent as propane (and propane is not as potent as butane). When converting a gas stove from NG to LP, the amount of gas per minute should be reduced to maintain the maximum BTUs the stove burners are designed to sustain.

If you are hardcore and want painful and confusing details about NG and LP pressure specs, try this: http://inspectapedia.com/plumbing/Gas_Pressures.php

Obviously, since this process deals with combustible gases, precautions should be taken to avoid gas leaks and to assure proper combustion. Sloppy work, sufficient improper combustion or leaks can be fatal. Recommendations? Get a professional or become one.

So What?

Well, to confess, I just had a personal experience trying to figure this stuff out.

The buyers of a stove I sold wanted to know if the burners worked. Initially, the plan was to unhooked my stove, move it out of the way, move the other stove from the outside into the kitchen and temporarily hook it up. Hmm… Naw. Too many big heavy stoves to be moved about.

Second plan; leave the sold stove outside, link together enough gas connector hoses to reach from the kitchen gas line to that stove, a distance of 24′.  I had enough connectors I salvaged from other stoves in my inventory to almost reach. Just one more would be needed. I also needed enough plumbing hardware to link the connectors. The hardware store sales associate had a blast trying to figure out all the MIP, FIP, flare parts needed to link six hoses together!

However, two things didn’t go well with the second plan. First, all those lovely little MIP, FIP and flared parts and the additional hose totaled nearly $100. And the entire 24′ long linked connectors hose leaked gas like a sieve.

Third plan. Leave the stove outside and hook it up to a propane tank. I returned the expensive collection of plumbing parts, bought a hose and regulator assembly and one part to connect the regulator hose to the manifold. I like this plan the best. My stove could stay put.  All the gas testing could be done outside so if there were any serious leaks, no big deal.

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This part need to connect the assembly to the manifold.

 

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Sweet! It all worked well enough to past the basic test. The four cooktop burners and the griddle burner worked.

NG/LP Gas Converting Options

Converting to a different gas fuel for the long haul is a different matter. There are a couple of options.

One Big Adjustment: One option is to install an NG/LP converter regulator inline to the manifold, that big pipe that supplies all the gas to the stove. This regulator allows you to convert your stove between NG and LP with just a flip of its cap and eliminates the need to change all of the stove’s orifices and valves.

Gas Line Regulators

gasReg

Lots of Little Adjustments: Another option is to adjust all the stoves’ valves and orifices.  There are a couple/few different types of independent gas flow regulators on the OKM to consider adjusting:

  1. Alltrol double valve orifices (8)
  2. Pilot light valves (4)
  • Each Alltrol double gas valve has two orifices can be adjusted to control the amount of gas that flows to a cooktop burner. One orifice controls gas flow is to the main burner, the other to the simmer burner. Four cooktop burners means a total of eight valve orifices to adjust.

flowRegulators

  • The cooktop burner, oven/broiler pilot light valves. On my stove there is a pilot light for the left side cooktop burners, one or the right side burners, one for the oven and one for the broiler. That’s an additional four items to adjust.

pilotValve

Ok, so that seems like a lot, right? Depending on the number of cooktop, oven and broiler burners , there could be quite a number of things to adjust. That makes a NG/LP convertible gas line regulator seem like a great time saver. At present they seem to range in price between $20 and $50. This webpage has decent details on how to convert from one gas type to another:  Converting Your Gas Range

But if you are trying to save pennies by not getting the inline regulator, remember you will most likely only have to do all those little tweaks once in a lifetime. It may take an hour or two, but that’s it.

11 thoughts on “Natural Gas & Propane Stoves”

  1. Hi there. I’m fixing up my OKM stove and was wondering if you had any advice on adjusting the oven and broiler flames. I was able to get the top burners adjusted but am not entirely sure how the flames should look in the oven and broiler. Should it be mainly blue like the tops ones? I do have my stove running on propane and even with the regulator installed I had to adjust the pilot valves, orifices, and venturi to get the proper flame height. Just not sure where to make adjustments for the oven/broiler. Any advice you can offer would be greatly appreciated. Also I bought a few parts from you on eBay and they were great and your blog has been so helpful in my restoration process!

    1. Hey Lacy! Nice to hear from you. Thank you very much. It is so nice to hear these pages help hearty OKM restoration DIYers. There aren’t too many brave souls like you. And I’m very glad you were satisfied with the parts you bought.

      Yes, the flames from the oven burner should look mostly blue but a propane flame is a little different than a natural gas flame. Check out this page. http://www.genuineideas.com/ArticlesIndex/sragasfuel.html The mixture of air and gas for the oven burner is controlled by the venturi, just like the cooktop burners. The oven burner venturi is located at the very bottom of the burner. If you open the bottom door, you should be able to see it. It’s probably in the back, the hardest place to reach when trying to make adjustments. 🙂

      1. Thanks so much! I think I finally got it adjusted right. Found the hard to reach Venturi and by adjusting that and tightening the orifice below it, I was able to get a good flame. Used the oven for the first time today! It’s been quite the project but have really enjoyed learning how it all works. They really are such sturdy and beautiful ovens. Now that I have one I can’t imagine using anything else… as long as I never have to move the thing again! Thanks again.

        1. Awesome! And remember to make sure the oven door closes as tight as possible. If not, replace the door springs. Also make sure the insulation is up to date, and that it is filling all areas inside the door. Several stoves that I have taken apart were in really poor shape just above the oven door (burned) because heat was escaping up and out the oven door.

          Yes, moving them is a bit challenging. I acquired one OKM where a previous owner had built in a permanent dolly. So the stove was and inch or two higher because it sat on wheels. It made moving it around SO much easier. I’m going to do that to mine during its next major maintenance & upgrade cycle.

  2. Hi,
    Great site, great info, and great pictures!
    The document on your “Alltrol Valve Operation” page indicates that fixed orifices are used for LP operation in place of the adjustable Natural Gas orifices. Have you found that you get acceptable burner performance using a NG/LP converter regulator and adjusting the NG oricifices and shutters accordingly, or do you think it’s worth trying to source some fixed LP orifices assuming one could find them?

    1. Hey Dax. Thank you. I hope you can find useful information to help take care of your OKM.

      I have not personally converted a stove’s valves to accommodate LP. My understanding is a converter regulator will reduce the gas flow thus saving you the trouble of adjusting the valve orifices and shutters. However, I found an webpage where a guy (Dave) addresses making LP orifices. He fills in the larger hole with brass, then drills a smaller hole. Frankly, I’d shell out a few bucks for the converter. 😉

      Here’s the link to Dave’s page: http://www.davegardner.org/GasInfo.html#Full

  3. Thanks for all the OKM information! I find your site invaluable as I restore a couple of 1954 OKMs.

    Can you please tell me where you bought the 46980 adapter pictured in the Propane conversion post? I’d like to test out the stove in my garage before I think about sticking it in the kitchen! So, like you just a quick temporary check on the firing.

    Thanks again and enjoy your day! Joe

    1. Any natural gas stove can be converted to propane and visa versa. Some vintage stoves already have the capacity built in. With others, a simple regulator needs to be attached to the main gas line to control the gas flow. Since propane gas is more potent than natural gas, the amount of propane gas that flows into the stove needs to be reduced. If you don’t feel like you can install the regulator, a competent plumber should be able to help.

      I’d love to sell you one of stoves, but unless you’re in or near Northern California, the cost of shipping might be a bit much. If you are within a couple hundred miles, let’s talk! 😀 However, I don’t have any restored stoves. They are as they were when their previous owners sold or dumped them. If you’re looking for a fully restored vintage stove, I can put you in touch with someone that sells fully restored vintage stoves. But they will be much pricier.

      And just to make your life more complicated, you might consider looking for a dual fuel (gas and wood) stove if it’s going into a rural area. That way, if you need heat for comfort or cooking, you will have a suitable backup if you run out of gas.

  4. Hi Lacy,

    I want to purchase an OKM stove. My house is all electric. We’ve looked at purchasing an expensive propane system but have decided to wait. So, were going to try to find a vintage electric stove. We haven’t been able to find one we’re back at square one looking at the OKM stove again, wondering if we can use it with a smaller propane tank. I’ve seen 40 gallon tanks. I saw a response you posted regarding using one to see if the stove was working, but is there any reason we couldn’t use one to run out stove all the time, if we ran a house outside?

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