Plumbing and gas fittings seem very overwhelming because of the terminology involved. It’s like a different language. Yet, it’s so important to get the correct fittings. The last thing you want is a gas leak in your home!
As it happens, it’s actually really simple to size your gas dryer fittings because they are pretty much all the same!
Almost all gas dryers use a rigid ½” IPS gas supply line, a ⅜” flare, a ⅜” NPT, and a ⅛” NPT plugged tapping. Some dryers have a rigid ⅜” gas supply line, necessitating an extra ⅜” female NPT.
All Gas Dryers Have the Same Fitting Specifications
The National Fuel Gas Code ANSI Z223 states you must have a rigid gas supply line to your dryer, with a shutoff valve installed within six feet of the dryer. If your local codes allow it, you may use a ⅜” flexible stainless steel gas connector.
Beyond this, when it comes to gas connections and the fittings needed, the top five manufacturers of gas dryers all use the same size fittings for their gas appliances. This is very convenient indeed!
Samsung, LG, GE, Whirlpool, and Maytag gas dryers require a rigid ½” IPS gas supply line, a ⅜” Flare, a ⅜” NPT, and a ⅛” NPT plugged tapping.
Should you require a longer gas pipeline of more than 20 feet, you will need a larger pipe with larger fittings.
If the above information looks like it was written in a secret code, don’t worry! We will get to the meanings of all of this further down.
First, I want to discuss why dryers all have the same specifications for fitting sizes.
Gas fittings are universal across gas dryer makes and models, but they are also the same for other gas appliances, such as your gas stove or water heater.
Having the same size fittings across appliance types, brands, and models makes installing and buying spares and replacement parts easier. And since this one size does the job safely and effectively for all the appliances, there is no need to complicate matters.
Now that we know the gas fittings are all the same. What exactly do each of these specifications mean, and what do the fittings do?
Explaining the Gas Dryer Fitting Sizes
When connecting any gas appliance, you will come across terms such as IPS, NPT and Flare in the instruction manuals. These are the required fittings and threads to connect your gas dryer to the gas supply line.
IPS stands for iron pipe size, a pipe sizing system used since the early 19th century. It is still used today in many gas applications.
If you use a rigid pipe to connect your dryer (which you must, according to the NEC), it must be at least ½” IPS. This is to ensure an adequate and efficient gas supply to your gas appliances.
The gas line on the dryer is not likely to be ½” in size, however. So, because you have a ½” gas supply line, it must be reduced to ⅜” to connect to the ⅜” gas line on your dryer.
This is easily done with adapter fittings.
Most fittings come with a male and female thread. The male threads are on the outside of the fitting, while the female threads are on the inside. The male threads screw into the female threads.
NPT (National Pipe Tapered)
NPT refers to a type of thread. Not just any thread, though. NPT is the most widely used thread in the US.
What makes NPTs unique is that the threads are tapered. They get slightly larger the closer to the fitting you get.
Having a tapered thread ensures a tight, sealed connection. By turning the NPT more, you are compressing the wider, lower threads. This compression provides a tighter seal.
Most gas dryers have a ⅜” NPT gas connection at the bottom of the dryer. You will need a ⅜” NPT female fitting to connect to the dryer.
Some people prefer to use an NPT elbow fitting to keep the gas line from kinking between the dryer and the wall, something that can happen far too easily.
When connecting a tapered thread use pipe joint compound, do not use Teflon tape.
The other side of the NPT fitting is usually a flared fitting to connect to the gas connection line. It’s flared because it needs to get wider to accommodate the ½” gas line.
Flared fittings are commonly used for gas appliances. The top edge of the male thread is angled. The female is inversely angled on the inside. When a flared fitting is tightened, the two flares from the male and female create a secure seal.
When joining flared fittings do not get pipe joint compound on the flares, only on the threads. This compromises the seal created by the flared tips.
NPT Plugged Tapping
The NPT plugged tapping is essentially a T-shaped NPT fitting with a “plug” in it. This connection allows you to connect a manometer and check the pressure of the gas entering your gas dryer.
The NPT plugged tapping is installed just after your shutoff valve.
The flexible connector is a flexible corrugated stainless steel tubing. They are often coated in a yellow casing.
The flexible connector allows you to easily pull your dryer away from the walls for cleaning and maintenance. They are not intended for long extensions to the gas supply line.
Flexible connectors can be fragile and prone to breakage and leaking. So, the shorter and more protected the connectors are, the better.
Local codes say a flexible connector may only be up to six feet long. However, most manufacturers only allow three to four feet. Check first in your manual so as not to void any warranties.
Never reuse a flexible connector, always replace it with a new one.
Do Gas Dryers Come With the Correct Fittings?
If you are lucky, your gas dryer may come with the fittings you need for installation. They will be the standard fittings as mentioned above to fit onto your dryer.
You will, however, need to check your gas supply line to ensure it is a ½” IPS. Some homes have a ¾” IPS gas line, depending on how many appliances your gas line needs to feed.
If you have a ¾” gas supply line, you may need to buy an additional fitting with a ¾” female NPT to connect to your gas supply line.
Make sure to measure pipes and fittings correctly to ensure you buy the correct ones.
Of course, if you want to change from natural gas to liquid propane, then you need to change the fittings.
Where to Find Replacement Fittings
Luckily, because most gas dryers have the same size fitting, finding replacement fittings is really easy. The best places to buy replacement fittings are at your local hardware store or online.
Here are some options for replacement fittings:
- LitOrange ⅜” male NPT to ⅜” male Flare (amazon link)
- ⅛” NPT tapered plug (amazon link)