How do you install a Watts pressure reducing valve?

Watts's sheet lists these installation notes, in this order:

1. 1The valve should be installed by a licensed contractor in accordance with local codes and ordinances.
2. 2Install it where it is accessible, with sufficient clearance for cleaning, service or adjustment.
3. 3Prepare the pipe. Before installing the valve, be sure the pipe ends are reamed and threads are cut to size. Valves with Quick-Connect tailpieces follow the separate Quick-Connect instructions.
4. 4Flush the lines to remove all loose scale, dirt and other foreign matter that can damage or clog the valve.
5. 5Point the arrow with the flow. Install the regulator with the arrow on the body pointing in the direction of the flow.
6. 6Mount it either way. The regulator may be installed vertically or horizontally, upright or inverted.
7. 7Start up. Open the cold water supply, then the hot water supply, and inspect for leaks.

Watts adds a tightening rule: to tighten the valve, first hand tighten, followed by 1/4 to 1 turn using a wrench.

### Where can it go?

Watts says the product is for interior or exterior applications and should not be buried directly in the ground. For exterior applications where the valve will sit in a vault or pit or be in contact with the ground, the valve should be installed in a meter box or vault, accessible for repair and adjustment, per local code.

### Why does Watts say to flush the lines first?

Watts says loose scale, dirt and other foreign matter can damage or clog the valve, and its troubleshooting section lists dirt or debris on the seat as one cause of high downstream pressure. Flushing the lines before you set the valve removes that risk at the start. Our page on why pressure rises after a Watts pressure reducing valve explains that problem.

### What should you check after start-up?

Watts's sheet builds a few checks into its other sections, and they double as a finish line for the job.

• Look for leaks. The start-up note says to open the cold supply, then the hot supply, and inspect for leaks.
• Read the gauge. The valve leaves the factory preset to 50 psi in a static condition, and Watts says any time a reducing valve is adjusted, you should use a pressure gauge to verify the setting.
• Watch for pressure that climbs. If downstream pressure is higher than the set pressure with no flow, Watts lists thermal expansion, pressure creep or dirt on the seat as the causes. Thermal expansion happens when water is heated in a closed system, and Watts says the system is closed when supply pressure exceeds 150 psi or a check valve or backflow preventer is in the supply piping.
• Try the cold tap. Watts says to open a cold tap briefly. If thermal expansion is the cause, the pressure is relieved at once and the system returns to the set pressure.

Watts also says you must make provisions for pressure relief protection of your plumbing system and components, and that a relief valve or a potable water expansion tank may be required. The valve has a built-in thermal expansion bypass, which Watts says keeps downstream pressure from rising to more than 10 psi above the supply pressure. Watts adds that the bypass will not stop the pressure relief valve on a hot water system from opening if pressure goes above 150 psi.

Some versions of the valve come with Quick-Connect tailpieces for tubing. Watts shows the steps for connecting and disconnecting.

To connect:

1. 1Mark the pipe. This is the pipe insertion depth.
2. 2Clean the pipe end.
3. 3If you are using PEX tubing, insert the pipe stiffener (provided) into the end of the pipe.
4. 4Push the tubing into the tailpiece up to the mark.
5. 5Insert the collet clip.

To disconnect:

1. 1Remove the collet clip.
2. 2Depress the collet.
3. 3Pull the tubing from the tailpiece.

The mark is the check that matters. If the tubing is not pushed to the line you drew, the joint is not fully seated.

Watts's sheet has a typical installation drawing. It shows a water meter, then a backflow preventer, then shutoff valves and pressure gauges on either side of pressure regulators, with lines running to the fixtures and to a sillcock. Two other layouts follow.

• Series installation. Watts recommends this where very high supply pressure must be reduced to a very low downstream pressure. Reducing the pressure in stages eliminates whistling and noise.
• Parallel installation. Watts recommends this where high flow or low flow demand is intermittent or occasional. It is also used for installations where service cannot be interrupted.

The gauges in the typical drawing echo Watts's adjustment rule. Any time a reducing valve is adjusted, use a pressure gauge to verify the pressure setting. Our page on how to adjust a Watts pressure reducing valve covers the bolt and the lock nut.

Watts's instruction to follow local codes and ordinances matters in the Valley. The City of Phoenix says it requires customers to install a pressure regulator on the customer's side of the water meter to ensure the pressure does not exceed 120 psi in the home or business, and that private pressure regulators are the responsibility of the home or business owner. The Building America Solution Center adds a design point: it says a pressure reducing valve creates a closed system, and that local plumbing codes should provide guidance on controlling thermal expansion. That is an installation question too, since a valve that closes the system may call for a tank or relief valve. Our page on whether you need a pressure reducing valve covers the code side, and do you need an expansion tank covers the tank.

### What should you have on hand?

Based on Watts's notes, plan for these items before you start:

• The valve, in a size that matches the pipe, and its instruction sheet.
• Tools to ream the pipe ends and cut threads to size, or the PEX tubing tools for the Quick-Connect version.
• A wrench for the last 1/4 to 1 turn.
• A pressure gauge for the check after start-up.
• Shutoff valves on both sides, as the typical drawing shows, so the valve can be serviced later.

Watts does not list a shutoff as a requirement. The drawing shows them, and they make the later strainer cleaning simpler. Our page on how to clean a Watts pressure reducing valve strainer shows why.

Watts says a licensed contractor should install this valve, so the honest answer is: for most homes, call one. Call also if you have galvanized pipe that will not thread cleanly, if the meter box or vault is hard to reach, or if you are not sure whether your system needs a tank or relief valve. HQ Plumbing & Air is licensed and insured, gives free estimates, quotes an upfront price, and offers 24/7 service.