By Brian Appelwick

In the point-of-use (POU) industry there are three main configurations of valves used—In-line, 90º and Tee style. All valves are used to control the water supply for reverse osmosis (RO) and/or under-the-sink filter installations, but are normally used in different circumstances. The vast majority of valves sold today are constructed of corrosion resistant plastic, which significantly reduces the leaching of substances into the drinking water supply. When considering the brand of valve to use, an important factor is the type of rubber used for the seals and o-rings.

Common materials used for seals and o-rings are ethylene-propylene-diene rubber (EPDM) and Buna-N. EPDM is the preferred choice because it is much more resistant to chemicals such as chloramines. Buna-N, when exposed to chloramines, swells and deteriorates at a much faster rate than EPDM, which can cause the valve to seize and not allow the user to turn off the water supply.

In-line valves
In-line valves are used in many ways. They are most commonly used in controlling the water supply when a system is teed off to a refrigerator’s icemaker or water dispenser. The In-line valve’s other major use is when a POU system can only be installed with a self-piercing or saddle valve and the installer wishes to have a reliable way to control the water supply to the system. Remember to check local plumbing codes prior to using a self-piercing or saddle valve, as they are illegal in many states. When choosing an In-line valve, a number of configurations exist. Push-to-connect fittings of ¼”, 3/8” and ½” or any combination thereof have become the most popular and the easiest to use. Other common configurations include ¼”-¾” male or female NPT threads.

90º valves
Ninety-degree valves have become standardized equipment on most RO storage tanks. The normal 3-gallon storage tank has a ¼” male NPT thread on the top. These valves are easily attached to the male threads with mating ¼” female NPT threads with three wraps of Teflon tape. Another use for the 90º Valves is a flow control for a POU filter. Most manufacturers have a recommended flow rate for the cartridges. Some 90º Valves are available with ¾” male NPT threads, the normal thread size in a #10 housing. The other end of the valve is available with ¼”, 3/8” or ½” push-to-connect fittings. This valve allows the installer to adjust the flow control, whether it is ½ gpm or 3 gpm. It also allows for the easy servicing of the filter.

T-style valves
T-style valves are designed to reliably connect to an existing water supply and tee off to a POU system. The tee incorporates a valve allowing for easy servicing of the POU equipment. The T-style valve quickly connects to any rigid pipe including copper (rigid and soft), chrome-plated supply tubes, cross-linked polyethylene, chlorinated polyvinyl chloride or any other pipe with an outside diameter of 3/8”, ½”, 5/8” or 7/8”. Installation time generally is less than five minutes. Many dealers also utilize the T-style valve when connecting to a refrigerator’s icemaker or water dispenser. They simply install the T-style valve between the final filter of the POU system and the faucet, and then connect the valve side of the tee to the line running to the refrigerator.

Push-to-connect fittings have been integrated into the ends of most valves for ease of use. Available sizes include ¼”, 3/8” and ½”, with the latter size designed for higher flow rates on commercial RO or POU systems. Dual o-ring seals are highly recommended for a leak-free connection. Also important is the use of high-quality tubing. Most manufacturers recommend a linear low-density polyethylene with a tight outside diameter tolerance of +0.001-inch /-0.004-inch.

When choosing a line of valves, carefully consider the construction. The small savings in price on the initial purchase can quickly be washed away when the dealer has to prematurely replace the valve due to inferior construction. Also select a line of valves that offers the diversity needed for your installation needs. The dealer needs to choose a supplier and/or manufacturer that stands behind their product and adequately inventories enough valves to meet your needs. Having to wait 4-to-6 weeks for a $3.00 valve can cause great frustration for a dealer when installations cannot be done due to a lack of installation supplies.

About the author
Brian Appelwick is sales manager for G.A. Murdock, a manufacturer and distributor of valves and fittings. He can be reached at (800) 568-7565 or email: [email protected]

Tips for success
A trend in the past several years has been the RO manufacturers switching to 3/8” tubing off the product side of the membrane. The main benefit of this is the increased flow rate out of the storage tank to the homeowner’s faucet and the refrigerator’s water dispenser. The dealer can often upgrade an older RO system easily when doing a routine filter change. This upgrade will not only create additional dealer income but will also enhance customer satisfaction, which may lead to a referral sale or rental.

Necessary steps and items for the upgrade include the following: 1. Replace the existing 90º valve on a 90º tank valve with a 3/8” fitting; 2. Using 3/8” tubing, connect the 90º valve to a 3/8” x 3/8” x ¼” Tee, connecting the ¼” product water line from the membrane to the ¼” side of the tee; 3. Connect the other side of the 3/8” x 3/8” x ¼” Tee to a 3/8” post-carbon filter; 4. Install a new designer style faucet construction for 3/8” tubing and a faster flow rate; and 5. If hooking up to a refrigerator, connect a 3/8” Tee to the post carbon filter, run 3/8” tubing to the refrigerator and use a 3/8” refrigerator connector to replace the brass compression nut on the back of the refrigerator.

By upgrading filters in the RO system, you will be improving the three major things your customer notices every day—the flow of the RO water, the appearance of the faucet and the quality of the water.


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