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Issue

Possible Cause

Corrective Action

Notes

Main Valve will not 
open

Closed isolation valves in pilot system.

Check isolation valves, ensure 
open. 

Insufficient supply pressure.

Check upstream pressure.

Depending on water 
source, supply pressure 
may not be controlled by 
valve operator.

Main valve stem assembly corroded/
damaged.

Inspect stem assembly, clean/
replace if necessary.

Blockage in pilot system.

Inspect & clean any installed 
pilot system strainers, check 
orifice/speed controls for 
blockages.

Missing fixed orifice assembly.

Verify installation of orifice; 
replace if required/missing. 

Pilot valve inlet isolation 
valve can be used as a 
makeshift orifice assembly 
by partially opening from 
full closed position. 

Improperly configured opening speed 
control (if equipped). 

Adjust opening speed control 
to verify functionality, adjust as 
required.

Standard setting for  
opening speed control is 
11/2 - 21/2 turns open from 
full closed position. Can 
be adjusted in field. 

Main Valve will not 
close

Closed isolation valves in pilot system

Check isolation valves, ensure 
open. 

Diaphragm is damaged

Conduct diaphragm seal test, 
repair and replace if necessary. 

Main valve stem assembly corroded/
damaged.

Inspect stem assembly, clean/
replace if necessary.

Blockage in main valve.

Perform freedom of movement  
test; if valve does not close,  
disassemble and remove  
blockage.

Worn/damaged valve seat. 

Perform seat sealing check; 
disassemble and inspect/repair 
seat if required.

Troubleshooting Guide

 

6          IOM-ACV-116-5_6116-5 2115 

EDP# 1917051 

© 2021 Watts

IOM-ACV-116-5_6116-5 2115 

EDP# 1917051 

© 2021 Watts         7

Summary of Contents for LFM116-5

Page 1: ...2 Setting the Pressure Controls 3 Maintenance Schedule 6 Trouble Shooting Guide 6 Valve Disassembly Instructions 8 ACV Schematic 11 Local building or plumbing codes may require modifica tions to the information provided You are required to consult the local building and plumbing codes prior to installation If the information provided here is not consistent with local building or plumbing codes the...

Page 2: ...nclude the optional opening speed control when used for Backpressure applications When the Model valve is located in line connecting two distribution zones the valve acts as a Pressure Sustaining Control Valve When pressure in the upstream zone falls below the pilot setting the valve modulates toward a closed position sustaining pressure in the upstream zone The valve will close if necessary until...

Page 3: ... to 21 2 turns from full closed position STEP 2 To ensure proper operation any trapped air will need to be bled off the valve cover during startup If your ACV includes a bleed valve use a flat head screwdriver to slowly open the valve See Figure 1 If your valve does not include a bleed valve bleed air by loosening a fitting on the valve or a plug at the highest point of the valve as sembly STEP 3 ...

Page 4: ...and close the up stream isolation valve until the inlet pressure drops to the desired setting STEP 7 Adjust the Sustaining Control screw IN clockwise until the inlet pressure begins to increase or OUT counterclockwise to de crease stopping at the desired pressure See Figure 2 4 IOM ACV 116 5_6116 5 2115 EDP 1917051 2021 Watts Figure 2 PV20C Pressure Sustaining Control Clockwise to increase inlet p...

Page 5: ...sing IF INSTALLED Opening Speed Flow Control Adjustment The Opening speed flow control allows free flow into the cover and re stricted flow out of the cover of the main valve If recovery of pres sure is slow upon increased downstream demand turn the adjust ment screw OUT counterclockwise increasing the rate of open ing IF recovery of downstream pressure is too quick as indicated in a rapid increas...

Page 6: ...e specification sheets for approximate cover capacity A continuous flow of water from the open port indicates a damaged diaphragm or loose disc diaphragm assembly Disassemble valve and replace diaphragm or tighten disc diaphragm assembly Test 2 Seat Seal Test 1 Close downstream isolation valve and install pressure gauges on an open inlet and outlet port of main valve 2 Open upstream isolation valv...

Page 7: ...mbly by partially opening from full closed position Improperly configured opening speed control if equipped Adjust opening speed control to verify functionality adjust as required Standard setting for opening speed control is 11 2 21 2 turns open from full closed position Can be adjusted in field Main Valve will not close Closed isolation valves in pilot system Check isolation valves ensure open D...

Page 8: ... Remove cover nuts and washers 3 Remove the cover If cover is not free to be removed loosen it by tapping upward along its outside edge with a dull cold chisel pic tured above a Large valves may require the installation of lifting eye bolts in order to facilitate cover removal installation ports are provided on the cover for this purpose 4 Remove the Disc and Diaphragm Assembly from the valve body...

Page 9: ... brush or by using a Mineral Dissolving Solution Inspect parts for wear and replace if necessary 7 Inspect valve seat If seat is not damaged removal is not necessary Valve seats 6 and smaller are threaded into the body of the valve and require a seat removal tool Figure 4 Table 1 details the tool dimensions for seat removal Valve seats 8 and larger are held in the valve body with stainless steel c...

Page 10: ... Nuts in a crossing pattern to ensure even distribution Test the Disc and Diaphragm Assembly for smooth travel by following the Freedom of Movement Test procedure in previous section 11 Test the integrity of the Seat Seal by following the Seat Seal Test procedure in previous section 12 Return valve to service by following instructions on the Technical Bulletin matching the valve function Size in 1...

Page 11: ...l 9 Stem Washer ASTM A276 304 Stainless Steel 10 Diaphragm Washer ASTM A536 65 45 12 Epoxy Coated Ductile Iron 11 Diaphragm Buna N Nitrile 12 Disc Retainer ASTM A536 65 45 12 Epoxy Coated Ductile Iron 13 Seat Disc Buna N Nitrile 14 Spacer Washer x5 NY300 Fiber 15 Disc Guide ASTM A743 CF8M 316 Stainless Steel 16 Shaft ASTM A276 304 Stainless Steel 17 Seat Ring ASTM A743 CF8M 316 Stainless Steel 17A...

Page 12: ...ot be responsible for any incidental special or consequential damages including without limitation lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly other costs resulting from labor charges delays vandalism negligence fouling caused by foreign material damage from adverse water conditions chemical or any other circumstances ov...

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