Zurn-Wilkins 34-375XL Installation Guide
Contents
1. RV SENSING E PORT O RING ry RV COVER J BOLTS RV SEAT Acar FLANGE RV SPRING GUIDE gt a RV SPRING _ 8 RV DIAPHRAGM lt gt RV RV PLUNGER _7 COVER O RING RV SENSING lt __ gt PORT O RING RV COVER to side can help it slide on over o ring Replace three RV COVER BOLTS fe oa remaining bolts amp NUTS 8 Place device in service and test per TESTING PROCE DURES FLOW CHARACTERISTICS MODEL 375 1 1 4 2 STANDARD amp METRIC 0 0 3 2 6 3 FLOW RATES V s 9 5 12 6 15 8 9 20 4 0 1 1 4 32mm 8 ba wg 15 TEN 8 10 en E r 2 bas a 5 34 0 50 100 150 200 250 FLOW RATES GPM Rated Flow Established by approval agencies ZURN ZURN WILKINS WILKINS 1747 Commerce Way Paso Robles CA 93446 Phone 855 663 9876 Fax 805 238 5766 3 www zurn com Troubleshooting When the relief valve discharges intermittently it can be almost always assumed that the device is functioning correctly and that the discharge is caused by systems problem such as inlet pressure fluctuations or water hammer due to quick closing valves PROBLEM POSSIBLE CAUSES CORRECTIVE ACTION 1 SUDDEN OR RAPID SPITTING 1 Drop in inlet pressure A Install an in line spring loaded check 2 Sudden increase in downstream valve upstream of backflow pressure due to water hammer from B In2. 1 1 1 4 2 2 1 2 6 8 10 a 150 A REPAIR KIT FOR 375 s 5 100 RUBBER PARTS i 1 1 4 2 RK114 375R u 30 COMPLETE INTERNALS 1 1 4 2 RK114 375 a VESSEL i 7 FLOW roa GPM i 829 Beia Rete ey Proper performance is dependent upon licensed qualified personnel performing regular periodic testing according to ZURN WILKINS specifications and prevailing governmental amp industry standards and codes and upon following these installation instructions Failure to do so releases ZURN WILKINS of any liability that it might otherwise have with respect to that device Such failure could also result in an improperly functioning device ZURN ZURN WILKINS WILKINS 1747 Commerce Way Paso Robles CA 93446 Phone 855 663 9876 Fax 805 298 5766 4 IS375 114 2 REV 4 13 www zurn com
3. Model 375 375B Reduced Pressure Principle 1 1 4 2 ZURN Installation U Testing Q Maintenance Instructions WILKINS CAUTION Installation of Backflow Pre venters must be performed by qualified licensed personnel Theinstaller should be sure the proper device has been selected for the particular installation Faulty installation could result in an improperly functioning device ZURN WILKINS Model 375 Reduced Pressure Principle Backflow Preventers are for use on water lines where a health hazard could exist if a backflow situation were to occur Proper performance is dependent upon following these installation instructions and prevailing governmental and industry stan dards and codes Failure to do so according to ZURN WILKINS Limited Warranty releases ZURN WILKINS of any liability that it might otherwise have with respect to that device Such failure could also result in an improperly functioning device Damage to the device could result wherever water hammer and or water thermal expan sion could create excessive line pressure Where this could occur shock arresters and or pressure relief valves should be installed downstream of the device 1 Before installing a Model 375 Backflow Preventer flush the line thoroughly to remove alldebris chips and other foreign matter If re quired a strainer should be placed upstream of the Backflow Preventer CAUTION Do not use a strainer in sel dom used emergen
4. ST NO 3 Purpose To test operation of the differential relief valve Requirement The pressure differential relief valve must operate to maintain the ZONE between the two check valves at least 2 PSID less than the supply pressure Procedure 1 Close by pass valve C and open by pass valve A 2 Open by pass valve B very slowly until differential gauge needle starts to drop Hold the valve at this position and observe the gauge reading at the moment the first dis charge is noted from the relief valve Record this as the opening differential pressure of the relief valve 7 2 TEST COCK 3 TEST COCK 1 TEST COCK FLOW FLOW gt ZR WILKINS 5 gt 175 PSIG 180 F 2 SHUT OFF 1 SHUT OFF VALVE VALVE BY PASS BY PASS VALVE A VALVE e Bono BY PASS VALVE B I VENT HOSE HIGH SIDE HOSE LOW SIDE HOSE Maintenance Instructions All Model 375 Reduced Pressure Principle Backflow Preventers must be inspected and maintained by licensed personnel at least once a year or more frequently as specified by local codes Replacement of worn or damaged parts must only be made with genuine ZURN WILKINS parts The ZURN WILKINS Certificate of Limited Warranty provides that failure todo so releases ZURN WILKINS of any liability that it might o
5. cy waterlines such as fire lines 2 Provide adequate space around the installed unit so that the test cocks will be accessible for testing and servicing 3 WARNING If installation of a Model 375 is in a building a suitable drain ar rangement MUST be provided to drain off spillage from the relief valve An air gap at least two times the pipe diameter mustbe provided between the relief valve and the drain piping to prevent a cross connection Air Gap AG 12 not intended to support weight of drain pipe CAUTION Do not pipe the relief valve solidly to a floor drain sewer or sump CAUTION An adequately sized drainis required to prevent possible water dam age due to relief valve discharge PROTECTIVE E gt ENCLOSURE OPTIONAL WATER METER 2 PIPE DRAIN LINE CAN NI BE ANY STANDARD PIPING MATERIAL A fir L INLET SHUT OFF l Witkans i IN 9 DIRECTION OF FLOW gt 4 Install valve at least 12 inches above surrounding flood level 5 Always consult local codes for installa tion methods approvals and guidance OUTDOOR INSTALLATION Model 375 Backflow Preventers may be installed outdoors only if the device is protected against freezing conditions Exposure to freezing conditions will result in improper function or damage to the device The insta
6. e gauge test kit TEST NO 1 Purpose Test 2 check valve for tightness against reverse flow Requirement The valve must close tight against reverse flow under all pressure differentials Procedure 1 Attach the HIGH hose to test cock 2 and the LOW hose to test cock 3 Close 2 shut off valve Open test cocks 2 and 3 Open by pass valves C and A and bleed to atmosphere until all air is expelled Close by pass valve A Open by pass valve B and bleed to atmosphere until all air is expelled Close by pass valves B and C Attach the VENT hose to test cock 4 Slowly open by pass valves A and C and keep by pass valve B closed Open test cock 4 Indicated pressure differential will drop slightly If pressure differential does not continue to decrease the 2 check valve is considered tight TEST NO 2 Purpose Test 1 check valve for tightness and record pressure drop across 1 check valve Requirement The static pressure drop across 1 check valve shall be greater than the relief valve opening point test 3 and at least 5 0 psid Procedure 1 Close by pass valve A 2 3 4 NO 0 2 Close test cock 4 and disconnect VENT hose from test cock 4 3 Open by pass valves B and C bleeding to atmosphere then close by pass valve B restoring the system to normal static condition 4 Observe the pressure differential gauge and note this as the 1 check valve PSID TE
7. e of the seal ring is unused it is possible to invert the seal ring This would be considered a tem porary solution to fixing a fouled check and should be re placed with a new seal ring as soon as possible 7 Inspect seat surface for nicks or dings and replace if necessary Use fingernail to check for dings Re grease seat o rings 8 Inspect seat o ring sealing areas in body and wipe clean 9 Reverse the above procedures to reinstall check valve assembly Drop 2 check assembly in body Then drop 1 check assembly in and turn until 1 spring retainer lines up with 2 seat Then push both assemblies into body Insert sleeve against checks Place sleeve down against flat surface and push on body with rocking motion Care should be taken to make sure the heavy spring is installed in the No 1 check valve 10 Rock body side to side to help o rings slide in If it does not drop in completely do not use screws to force it An overly greased o ring might slide out of groove at top of ball valve Use a screw driver to push o ring back in groove then push body down in SERVICING RELIEF VALVE 1 Remove three bolts holding relief valve module to body 2 Pull down and remove relief module to expose seat and seal ring These can be inspected without further disas sembly CAUTION do not lose small o ring or large o ring that fit between module and check body 3 To inspect diaphragm or replace seat diaphragm stem assembly remove the four
8. k valves by slightly opening each of the four test cocks 3 Slowly open the downstream shut off valve The Model 375 Reduced Pressure Principle Backflow Preventer is now in service 4 If spitting or intermittent discharges from the relief valve are noted it could be a result of pressure fluctuation and or a water hammer condition in the system If such conditions exist install a ZURN WILKINS water pressure reducing valve a Model 40XL2 check valve or a Model 1250XL water hammer shock arrester in compli ance with industry standards as needed 5 After the Model 375 has been prop erly installed test the device see TEST PROCEDURES If the device fails the test remove the first and second check valves and thoroughly flush the device If the relief valve fails to operate properly inspect the sensing passage for clogging see MAINTENANCE INSTRUCTIONS Clean rubber seals of all debris and place unit back in service Proposition 65 Warning This product contains chemicals known to the State of California to cause cancer or birth defects or other reproductive harm In accordance with U S Federal Safe Drinking Water Act Lead Free requirements as of January 4 2014 this product can only be used in water systems considered non potable Please contact your local water utility for further requirements Testing Procedures MODEL 375 REDUCED PRESSURE PRINCIPLE ASSEMBLY Equipment Required Differential pressur
9. llation location must be kept above 32 F All the basic installation instructions apply If installation is in a pit or vault the Back flow Preventer must never be submerged in water because this will cause a cross connection Make sure that the pit or vault always remains dry by providing ample drainage INDOOR INSTALLATION Indoor installation is preferred in areas that are subject to freezing conditions All the basic installation instructions apply to such installations PARALLEL INSTALLATION Where uninterrupted service from a single meter connection must be maintained two or more Backflow Preventers may be con nected in parallel All the basic installation instructions apply to parallel installation Be sure to allow adequate room between the units for testing and repair PLACING THE DEVICE IN SERVICE After the installation of a Model 375 has been completed place the unit in service as follows 375 REDUCED PRESSURE PRINCIPLE 1 Start with both shut off valves closed Slowly open the inlet shut off valve until the backflow preventer is completely pressur ized A brief discharge from the relief valve may occur while the device is pressurizing The discharge should cease by the time the shut off valve is fully open Device should function properly If the discharge does not stop refer to MAINTENANCE INSTRUC TIONS for repair procedures 2 After the device has been pressurized vent all trapped air from both chec
10. screws holding the two module halves together CAUTION do not lose small o ring 4 Remove stem assembly Inspect diaphragm and plunger o ring for damage Replace any damaged parts and ap ply a light coat of grease to plunger o ring and place on plunger CAUTION stem assembly is internally spring loaded Seat can be unscrewed from plunger to replace diaphragm or spring The seat surface must not be nicked during disassembly or reassembly 5 There are two o rings that fit into the cover surface one large one small These o rings should not be greased Insert stem into cover Place second module half onto cover Push the seat down into the cover with your thumb to align diaphragm bolt holes with cover and then insert four bolts and tighten 6 Inspect o ring that seals between module and check body Replace if necessary Apply grease to the o ring and then place on step on check body Place small o ring into groove between the two front bolts holes in relief valve module 7 Slide relief valve module onto check body Rocking side SEAT O RING a 1 CHECK SEAT E O SS ori SCREW C gt SEAL RING RETAINER CE POPPET SEAL RING Cpp roPPeT 2 CHECK ASSY G SPACER 1 1 4 amp 1 1 2 1 CHECK SPRING 1 CHECK SPRING RETAINER BODY BODY OUTLET O RING BOLT Na SLEEVE BOLT f O RING BODY INLET 7 OO OCG SLEEVE RV SEAL RING RV ac ae RV SEAL 2 RING RETAINER RV BODY O RING
11. stall pressure reducing valve up quick closing shut off valve installed stream of backflow unit downstream C Install in line spring loaded check valve downstream of backflow as close to source as possible but not closer than 4 feet 2 LIGHT INTERMITTENT DRIP 1 Slightly fouled 1 check A Clean 1 check and turn check valve seal ring over or replace Continuous discharge of the relief valve signifies a failure of some part of the device To help determine the specific area of failure close the 2 shut off valve If the discharge stops the 2 check requires service If the discharge continues the 1 check requires service 1 CONTINUOUS DISCHARGE 1 Fouled 1 check A Clean check valves and turn check 2 Fouled relief valve seat valve seal rings over or replace 3 Fouled 2 check B Clean relief valve seat and turn relief valve seal ring over or replace In summation the amount of discharge is proportional to degree of fouling Most problems occur in the 1 check which is where debris enters the backflow preventer first Performance Characteristics SPECIFICATIONS Maximum working water pressure 175PSI Capacity thru Schedule 40 Pipe Maximum working water temperature 180 F 7 Hydrostatic test pressure 350PSI 10 ft sec Relief Valve Discharge Rates 3 13 20 5 eS MODEL 375 475 8 975RPERPDA o BACKFLOW PREVENTERS 8 200 rd 3 4
12. therwise have with respect to that device Such failure could also result in an improperly functioning device The Model 375 Reduced Pressure Principle Assemblies should be thoroughly flushed after backflow conditions occur to prevent any type of corrosive deterioration to its components Failure to do so could result in malfunction of the device GENERAL MAINTENANCE 1 Clean all parts thoroughly with water after disassembly 2 Carefully inspect rubber seal rings diaphragms and o rings ZURN WILKINS 2 1747 Commerce Way Paso Robles CA 93446 Phone 855 663 9876 Fax 805 238 5766 for damage 3 Test unit after reassembly for proper operation see Testing Procedures SERVICING CHECK VALVES 1 Close inlet and outlet shut off valves 2 Open No 2 No 3 and No 4 test cocks to release pressure from valve Unscrew 4 screws holding body down lift valve body upward Twist and remove sleeve from body Using finger or blunt object push in outlet end of body both checks should slide out the body inlet A short object like a socket can be placed on a flat surface Place body over object so it pushes into valve outlet and push down on body Twist spring retainers counter clockwise to remove from seat and access poppets Inspect the rubber seal ring for cuts or embedded debris To remove seal ring remove screw and seal ring retainer ZURN WILKINS 3 4 www zurn com Maintenance Instructions If the reverse sid
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