Changing From LPG to Natural Gas

There are numerous guides for this:

Converting Ranges from Natural to L.P. Propane Gas

Converting LPG and Natural Gas Appliances | ELGAS - LPG ...

Converting Gas Appliances - Propane and Natural Gas ...

Different fittings need to be used for burners and pressure regulation. This is not a job for the uninformed amateur, for both safety and continuing insurance cover considerations. In the UK you would consult a CORGI-registered Gas Fitter to do the work, many of whom you would find by opening up your Yellow Pages telephone directory.

A lot of the more modern stoves are already set up to work with both fuels and just need a fitting changed and or a screw adjusted on the regulator that can be found either in the back or under the top lid.

Stoves are not the same as a baking oven. Ovens can have multiple controls and safety requirements some what more complex than a stove.

Not a good idea to compare them from an operational viewpoint.

The replies by Lyn and Crabtree are spot on. This is not a do it yourself job. It is not just a matter of changing orifice size. Gas delivery pressure, and air to gas mixing ratios for the two gases are completely different. I would not attempt to do this unless the appliance was specifically designed for both gas services, and the conversion was performed by a qualified technician. The consequences are either an explosion or CO poisoning.

Make life simpler and safer for yourself. Contact the manufacturer/distributor/service group and ask them if there is a conversion kit available for that model from propane to natural gas. If there is one it will contain all the parts necessary to make a safe conversion. I the US they are available for many barbeque grilles. They are also available for many household stoves although not for all. They are almost always available for industrial and baking ovens.

To go from propane to nat gas will require more than changing the orifice. Let them supply everything.

Good Luck, Old Salt

You should also note that the pilot flame jets will need altering also. The new jet size will depend on the original jet size for LPG and converted to Nat gas, the air mixing arrangement must suite both types of gas otherwise new burners must be fitted.

For safety please consult with a local gas fitter.

More information required. Are you a qualified gas engineer? If so the following will prompt your memory.

What type of burner is it:

1. Atmospheric injected ribbon or bar burner. In that case a simple jet size change will do it if the gas pressures are in the correct ratio.
2. Air blast burner. Easiest of all if you have a flue gas analyser. Screw the obturator in until the flame looks tight & blue and then check with a flue gas analyser trim as necessary to maximise CO2 and minimise CO. Check at low fire and trim Zero pressure regulator for the same conditions.
3. Nozzle mixing burner. Usually a replacement gas spud is required with different size holes, possibly a different number of holes in a different arrangement.

Of course if you are not qualified for this type of work with certificates to prove it then hire someone in who is qualified and stop putting peoples life at risk.

Propane vs. Natural Gas: What's the Difference?

BY JOSH GARRETT

The flames look the same, but the fuels are different. (images: energyaustralia.com.au and sfgasworks.com)

Let's start with what you probably already know: natural gas is a fossil fuel in a gaseous state that travels through pipes to people's homes for use as a fuel for cooking, heating and water heating. Many people believe that propane is the same gas stored in tanks of various sizes instead of delivered by pipe, but that is not the case. Propane is in fact a different fuel from natural gas, though the two are closely related. So what's the difference between these two fossil fuel cousins?

Chemical Makeup

Natural gas that is drilled out of the ground is actually a mishmash of several gases. Methane is the biggest component of unrefined natural gas, and is the one gas left at the end of the refining process. So when someone uses natural gas for cooking or heating in their home, they are essentially burning methane with an odorant (added for safety, it makes gas leaks more easily detectable) and a few other additives. Other components of unrefined natural gas include butane, ethane, and propane. That's right, propane is actually a part of unrefined natural gas that is separated out during the refining process sold separately. Both refined natural gas and propane are hydrocarbons (nature-formed compounds made up of hydrogen and carbon). Propane's chemical formula is C3H8 and methane's is CH4.

Physical States

Unrefined natural gas, as the name implies, exists underground in a gaseous state. It is extracted as a gas and refined as a gas, but can be stored as a gas or a liquid. By changing temperature and pressure, refined natural gas can be liquefied-into a substance called liquefied natural gas (LNG)-for storage. Similarly, propane is extracted from unrefined natural gas as a gas, but unlike refined natural gas (methane), it is almost always stored and transported in its liquid state, as a substance called liquefied propane gas (LPG). This is why propane is usually sold in gallons (a measure of liquid volume) and natural gas is sold in cubic feet (a measure of gas volume). LPG is stored in pressurized tanks, and the pressure inside the tanks keeps the propane in its liquid state. But as soon as the tank's valve is opened and the LPG moves out of the tank, it escapes the pressure and vaporizes into gas state. This formerly-liquid-now-gas form of propane is what fuels stoves, heaters, and other residential appliances.

Energy Content

Which packs more power, natural gas or propane? The pretty clear answer is propane. The energy content of most fuels is measured in British Thermal Units (BTUs), so comparing the BTU content of identical quantities of different fuels gives an accurate comparison of energy content. Although propane is transported and stored as a liquid, we'll refer to its gaseous state for the sake of a more direct comparison with natural gas. One cubic foot (ft3) of natural gas contains 1,030 BTUs and one cubic foot of propane gas contains 2,516 BTUs, giving propane about twice the energy content of natural gas. Propane101.com offers this comparison to put BTU values in the context of heating fuel:

• 100,000 BTU/hr furnace will use about 97 cubic feet of natural gas (100,000 ÷ 1,030 = 97.1) in one hour
• 100,000 BTU/hr furnace will use about 40 cubic feet of propane (100,000 ÷ 2516 = 39.7) in one hour

So there you have it. Propane, by nature a component of natural gas, is separated out during the refining process to become a more powerful fuel. Now that you're educated, take it on yourself to drop some knowledge on the next person you hear refer to propane as natural gas or vice versa.

Source: http://blog.propane.pro/lpg/15890127/

You may not be able to legally do this as the regulations governing the operation and built in safety features of these ovens MAY have changed. The authorities expect that as the older ovens come of an age to require a rebuild the gas fitter called to do the job will condemn it and a new, safer one will be required to be bought.

I struck this myself. The manufacturer refused to sell me the parts I asked for, offering the above explanation.

Jim

Thank you,

Of course I'm not the registered gas fitter and also i'm not the person that will do the job, since i'm in charged with this project i.e facility with electrical background i would like to know what are the outsource vendor do to my equipment.

Your advice was highly appreciated.