Installing a gas dryer requires some knowledge about standard fittings. Proper fittings can be purchased at any hardware, plumbing or home remodeling store. Some states may require a licensed plumber, gas fitter or contractor to complete the installation. Regardless of who installs the gas dryer, understanding the basics about the types of fittings used for gas connections can help prevent leaks and pressure issues.
Fittings designed for a gas dryer are metal connectors, such as elbows and adapters, that join and connect the piping from the dryer to the home's gas source. The fittings can change the direction of the gas flow or regulate and block the flow as required. Gas dryer fittings are not usually supplied when purchasing a gas dryer -- the buyer or installer must purchase them separately. However, the installation directions will outline which items are needed and what the proper assembly of the fittings should be.
An elbow is the first fitting attached to the dryer's gas inlet pipe -- the pipe that leads directly into the dryer system and is part of the dryer equipment. The elbow extends from the fixed inlet pipe and turns the flow of the gas. Elbow threads should match the gas inlet pipe for a tight fit. Elbows and other fittings should never be reused due to wear; always replace fittings when installing a new gas dryer or updating the dryer with a replacement model.
An adapter is attached to the elbow and never attaches directly to the dryer's gas inlet pipe. The flare end of the adapter is turned away from the dryer and is used to attach a flexible, metal gas line connector. The female or flare end of the adapter is kept free of sealant, oil and grease for a tight fit.
Adapters are placed at both ends of the flexible gas line; the second adapter is different from the first adapter. The second adapter includes a pipe plug that is used to verify gas inlet pressure. The third adapter, attached to the pipe plug adapter, includes a gas shut-off valve, which is typically connected to the home's gas supply.
Gas dryers, and other gas appliances, use a national standard pipe thread known as NPT. NPT uses a tapered thread on threaded fittings and pipe -- the standard allows buyers to purchase fittings that match threaded pipe. NPT is a standard defined jointly by the American National Standards Institute, known as ANSI, and the American Society of Mechanical Engineers, known as ASME. NPT pipe for a gas dryer uses a male thread and all fittings attached to the NPT pipe use a female thread. The threading effectively seals the coupling and prevents a gas leak. The addition of a pipe compound at each coupling further seals the fitting.