Zurn Wilkins ZW209FP Pressure Reducing Valve Assembly

Description

The Zurn Wilkins Model ZW209FP is a pilot-operated pressure reducing valve designed specifically for fire suppression systems to reduce high inlet pressures to a safe and stable outlet pressure. The pilot assembly reacts to changes in downstream pressure, allowing the main valve to modulate between the closed and open position, ensuring a constant downstream set pressure. Pressure regulation is not dependent upon flow rate, resulting in minimal pressure loss through the valve. The ZW209FP comes standard with red epoxy coating internally and externally for corrosion protection, as well as pressure gauges for quick and easy maintenance or repair. The ZW209FP is available in both globe and angle pattern bodies.

Models and Specifications

The Zurn Wilkins ZW209FP is available in several configurations:

• ZW209FP: Class 300 Flanged, Max 300 psi Inlet
• ZW209FPG: Grooved, Max 300 psi Inlet
• ZW209FPX: Class 150 Flanged, Max 250 psi Inlet
• ZW209FPTH: Threaded, Max 300 psi Inlet

Installation / Start-up

Installation Notes

[Note: Prior to installation of the ZW209FP, ensure that all debris is flushed out the piping system before installed.]

[Caution: The recommended installation orientation for Automatic Control Valves (ACVs) is horizontal, with the valve cover up. 6" and larger valves should only be installed horizontally, with the valve cover up, due to the difficulty of properly bleeding air out of the cover on valves installed in the vertical orientation. In addition, the horizontal positioning of the larger valves avoids premature wear due to the mass of plunger assemblies as well as allows for greater accessibility during annual inspections and maintenance.]

1. During the installation of a ZW209FP in a sprinkler system, Underwriter Laboratories (UL) requires NFPA 13 "Standard for Installation of Sprinkler Systems" be followed.
2. Upon installation, UL also requires that the ZW209FP be tested in accordance with NFPA 13 or NFPA 14. Thereafter, the valve shall be inspected, tested, and maintained in accordance with NFPA 25 "Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems". [Note: Initial testing must be done with the design inlet pressure so the proper outlet pressure can be verified.]
3. For making adjustments and servicing, allow for adequate space around the valve.
4. When installing a ZW209FP, gate valves installed on both inlet and outlet are recommended for maintenance, allowing for isolation of the valve.
5. Position the ZW209FP in line matching the direction of flow as indicated on the valve model tag. Once attached to the line, double-check all fasteners/bolts in the pilot system and on the main valve are tight and there is no damage prior to pressurizing the system.

[Note: Pressure in some applications can be very high, so be thorough in checking and inspecting for proper installation and makeup.]

Valves installed in sprinkler or standpipe systems shall have the following:

1. Union or rubber gasket fittings installed immediately upstream or downstream to permit replacement.
2. A relief valve (at least 1/2" size and 175 psi max.) installed on the downstream side and plumbed to a safe drainage.
3. Pressure gauges installed on the inlet and outlet.
4. Shall not be set for less than 50 psi.

It is suggested that a line size tee connection be installed downstream of sprinkler system valves to allow flow testing as required every five years per NFPA 25.

[Note: Bleed all trapped air from supply riser and sprinkler system. Trapped air may cause outlet pressure fluctuations at low flows.]

Start-up Procedure

[Caution: To prevent personnel injury and damage to equipment, check that downstream venting is adequate prior to start-up and test procedures. All adjustments under pressure should be made slowly while under flowing conditions. If the main valve closes too fast, it may cause surging in upstream piping.]

1. Slowly open the upstream shutoff valve only enough to fill the main valve assembly and pilot system. Prior to pressurizing the valve assembly, it is also recommended that a ZPI valve position indicator be installed to aid in verifying proper valve movement.
2. As the valve is filling with water, it is necessary to bleed the main valve and pilot system of air. To vent air, partially open or loosen the highest plugs or fittings in the system. The ZPI valve position indicator is a great location, as it has a test cock at the top to vent air pressure. It may be necessary to bleed the system more than once. After removal of air in the system, tighten all loose fittings. [Note: If the valve is installed vertically, it will be necessary to loosen some upper cover bolts until you have vented all the air from the cover chamber.]
3. At this point, with the upstream shutoff valve partially open, slowly open the downstream shutoff valve. Flow will begin to occur and pressure should build up in the valve and eventually stabilize.

[Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov]

[Advertencia: Cáncer y daño reproductivo - www.P65Warnings.ca.gov]

[Avertissement: Cancer et néfastes sur la reproduction - www.P65Warnings.ca.gov]

Flow Rates for Setting Valve (Table 1)

[Note: The suggested flow calculations are based on the flow through Schedule 40 pipe. Maximum continuous flow is approximately 20 ft/s (6.1 m/s) & maximum intermittent is approximately 25 ft/s (7.6 m/s), and minimum continuous flow is approximately 1 ft/s (0.3 m/s). Many factors should be considered in sizing pressure reducing valves, including inlet pressure, outlet pressure, and flow rates. For additional system protection, a pressure relief valve (1/2" min) shall be installed downstream of the pressure reducing valve.]

Schematic Diagram Components (ZW209FPG)

• 1. Main Valve
• 2. SXL "Wye"
• 3. Pressure Gauge
• 4. Restriction Tube Fitting
• 5. PV-PRD Pressure Reducing Control

Operation

The Zurn Wilkins ZW209FP utilizes a pressure reducing pilot valve that installs on the discharge side of the control circuitry. The pilot Model PV-PRD is a direct acting, normally open, spring loaded, diaphragm actuated valve. The operation of the ZW209FP begins with accurately sizing the valve, then fine tuning the control circuitry by adjusting the PV-PRD to the desired downstream pressure. Inlet pressure is piped to the inlet of the PV-PRD. A sensing line runs internally from the discharge side of the pilot to its lower control chamber under the diaphragm. Thus, downstream pressure exceeding the preset of the pilot acts to close the pilot valve while the adjustable spring in the pilot seeks to keep it open. The result is a modulating action in the pilot that is transmitted to the cover of the main valve. This creates a mirror modulation of the diaphragm assembly in the main valve. Downstream pressure is maintained with narrow limits regardless of changing flow rates or varying inlet pressure.

Drip Tight Closing Operation

With the use of a three-way pilot control, inlet pressure is directed to the cover, where the pressure forces the valve closed.

Full Open Operation

Using a three-way pilot control, pressure relief (typically to atmosphere) can be controlled to the cover, which enables the inlet pressure to open the main valve.

Modulating Action

Utilizing a Wilkins modulating control system, pressure changes to the cover can be controlled, allowing the valve to throttle and compensate for changes.

Flow Characteristics

Body Minimum Friction Loss

This chart illustrates the minimum friction loss through the valve body based on flow rate (GPM) and valve size. [Note: Minimum inlet pressure is 10 psi higher than the set point or the additional body friction loss at the intended flow, whichever is higher. Friction loss may be important at flows above 20 ft/s.]

Pressure Reduction Limit

This chart displays the relationship between inlet and outlet pressure, defining safe operating limits. It identifies:

• [❗] UL Limit Damage Zone: Operation in this area is prohibited.
• Noise Limit Zone: Potential for audible noise.
• Cavitation Damage Zone: Intermittent operation is permissible.
• Safe Operating Zone: Recommended area for normal operation.

Maintenance Instructions

General Maintenance

In addition to complying with UL standard NFPA 25 every five years, scheduled preventative maintenance and inspection is highly recommended. It is also recommended that a repair kit with a new diaphragm, disc, and o-rings be on hand before work begins.

[Warning: With the ability to perform inspections and maintenance without removal from the system, it is very important that all shut-off valves be closed and all pressure relieved in the valve before beginning disassembly. Failure to do so can result in personnel injury or equipment damage.]

Main Valve Disassembly

1. With all isolation valves closed to the ZW209FP, begin slowly removing the flare fitting in the pilot system until residual pressure is removed. After excess pressure has been relieved, begin removal of pilot tubing to the cover.
2. Begin loosening cover bolts and remove the cover, lifting up to slide the cover bushing off the plunger shaft. For valves larger than 6", it is recommended that lifting lugs and a hoist be used due to the excessive weight of the larger covers.
3. Once the cover is removed, the plunger spring and spring washer can be removed. Then remove the diaphragm assembly by grabbing the stem or lifting from two sides of the diaphragm. Be sure to lift straight up to avoid binding the stem in the seat bushing, as damage can occur. [Note: Again, with the larger size valves (6" and up), it is recommended that a lifting lug and hoist be used to remove larger plunger assemblies.]
4. Place the diaphragm assembly in a vise with the bottom hex secured. Remove the stem nut and inspect threads for damage, corrosion, or pitting.
5. After inspecting the stem and removing the nut, the diaphragm assembly can be dismantled. When disassembling, be sure to clean, inspect, and save all components. Replace any damaged components as necessary.
6. Next, clean and inspect the seat inside the main valve body. If excessive water deposits are present, fine grit sandpaper can be used to clean. The seat is designed to be removed, but typically does not require removal. If damage is noticeable or the seat is excessively worn, replace the seat before reassembly.
7. Refer to www.zurn.com to find the ZW209 instruction sheet for more detailed instructions for disassembly and reassembly of the main valve.

Main Valve Reassembly

Prior to reassembly, clean, inspect, and replace any parts as needed.

1. Using a vise, the diaphragm assembly can be held and assembled in the reverse order as the disassembly section.
2. Clamp the valve stem hex in a vise and reassemble the diaphragm assembly. Make sure to center the diaphragm on the plunger before placing the diaphragm disc. Refer to the ZW209 instruction sheet at www.zurn.com or call product support 877-222-5356 for further assistance.
3. Once the diaphragm assembly is assembled, gently lower the stem into the seat guide. Rotate the diaphragm as needed until bolt holes line up with body bolt holes.
4. Install the spring, then the cover. Tighten bolts in a cross pattern. Be careful not to pinch the diaphragm when inserting and tightening cover bolts.
5. Reattach the pilot assembly and tighten all bolts and fittings as needed. Test the system per UL standard NFPA 25.

PV-PRD Valve Maintenance

The PV-PRD pressure reducing control may be installed in any position. There is one inlet port and two outlets, for either straight or angle installation. A flow arrow is marked on the body and should be oriented as needed.

PV-PRD Disassembly

[Note: Prior to disassembly, relieve all pressure in the pilot system and then remove the PV-PRD.]

1. Secure the valve body and remove the main cap on the bottom of the valve using an adjustable wrench.
2. Use a 13 mm socket to remove the plunger.
3. Next, remove the adjustment cover (plastic cover), 3/8" adjustment bolt with nut, 8 socket head screws around the pilot bell using a 5/32" hex key, spring, and spring disc.
4. At this point, the PRV stem yoke is free to move and can be slid out of the valve body.
5. Continue to remove the 5/16" diaphragm nut, lock washer, and diaphragm retainer.
6. After completely disassembling, thoroughly clean and inspect all components before reassembly. Replace any parts as necessary after inspection.
7. The pilot seat generally does not need to be removed, but if after inspection it requires replacement, it can be removed with a 1/2" socket.

PV-PRD Reassembly

Reassembly of the PV-PRD is the reverse of disassembly.

1. Install the new o-ring on top of the pilot yoke threads, followed by the new diaphragm and diaphragm retainer. Then place the lock washer over the pilot yoke stem along with the 5/16" diaphragm nut and tighten. Diaphragm bolt holes must be centered on the yoke legs. See following diagram.
2. Next, carefully slide the yoke assembly into the body and around the pilot seat.
3. Then attach the plunger to the bottom of the pilot yoke via the main cap hole and tighten with a 13 mm socket.
4. Install the main cap in the bottom of the valve body with a new o-ring.
5. Install the spring, spring disc, and pilot bell on the valve body.
6. Insert socket head cap screws into the pilot bell holes and thread into the valve body. Tighten all screws in a cross pattern.
7. Install the adjusting screw by hand with the jam nut. Set the valve once reinstalled into the main valve pilot system. For setting the pilot, refer to the "Start Up" section on page one. For further assistance or ordering replacement parts, go to www.zurn.com or call product support 877-222-5356.

PV-PRD Specifications

• Adjustment Range Pressure (Flowing residual outlet pressure): 50-165 psi
• Max Static Outlet Pressure: 175 psi
• Max Inlet Pressure: 300 psi

[Note: All adjustments should be made with a pressure gauge and while flowing water through the main valve.]

PV-PRD Component List

The PV-PRD valve consists of the following components:

• 1. BODY, Lead Free Brass
• 2. PLUNGER, SS W/BUNA NITRILE 90 SHORE
• 3. MAIN CAP, Lead Free Brass
• 4. ADJUSTMENT COVER
• 5. 3/8"-16 ADJUSTMENT BOLT, BRASS
• 6. 3/8" PILOT SEAT, SS
• 7. 20-200 PSI SPRING, CHROME SILICON
• 8. DIAPHRAGM DISC, SS
• 9. SPRING DISC, SS
• 10. PILOT BELL, BRASS
• 11. O-RING, BUNA NITRILE NSF LISTED
• 12. 5/16"-18 DIAPHRAGM NUT, SS
• 13. 10-32X5/8 SOCKET HEAD CAP SCREW
• 14. DIAPHRAGM, NYLON REINFORCED BUNA NITRILE
• 15. PRV STEM YOKE, SS
• 16. 3/8"-16 JAM HEX NUT, SS
• 17. 5/16" INTERNAL TOOTH LOCK WASHER, SS
• 18. O-RING, BUNA NITRILE NSF LISTED
• 19. UL TAG RED, BRASS
• 20. 3/4" NPT PLUG

[Note: Line up diaphragm screw holes with holes in body. Move yoke up and down checking for yoke contacting or dragging on valve body.]