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Standard Components

Operation

The One-Way Flow Altitude Automatic Control Valve (ACV) with 
Pressure Sustaining Feature is designed to open, allowing flow into a 
reservoir or elevated storage tank (tank fill), and close drip tight when 
high water level is achieved. The valve will also throttle to sustain a min-
imum upstream pressure during tank filling operations. The Altitude Pilot 
remotely senses static tank head pressure (water level) through a field 

P(L)

1

X

X

5

4

2

X

Y/FC

CLOSES VALVE

OPENS VALVE

FLOW

3

(Tank Sense Line)

6

7

1.  Prior to installation, flush line to remove debris.

2.  Install valve so the flow arrow matches flow through the line, and gauges to monitor valve inlet and outlet pressures. A Position 

Indicator can be installed to provide visual indication of valve position and operation without disassembly.

3.  Install isolation valves upstream and downstream of the main valve.

 

Note: 

If using butterfly valves, ensure valve disc does not contact the main valve.

 

4.  Provide adequate clearance for valve servicing and maintenance. Refer to valve servicing dimensions on next page. Avoid installing 

valves 6" and larger in the vertical position (main valve stem horizontal). Automatic Control Valves (ACVs) are designed for horizon-
tal in-line installation, with the cover facing up (main valve stem vertical). Slow operation or premature stem and guide wear may 
occur if valve is not installed according to factory recommendations. Consult factory for detailed engineering review prior to order-
ing if valve is to be installed other than horizontally in-line.

5.  If valve is equipped with a pilot control system, extra precautions should be made during installation to protect the piping circuit 

from damage. Only remove the pilot control system from the valve if necessary. Tubing and fittings should be kept clean and 
replaced exactly as removed. Consult appropriate hydraulic schematic to ensure proper re-assembly.

6.  Check to confirm that the sense line is installed and connected.

7.  After installation, vent entrapped air from valve cover and pilot system by following instructions on Technical Bulletin.

Start-up of an automatic control valve requires that proper procedures be followed. Time must be allowed for the valve to react to adjustments 
and the system to stabilize. The objective is to bring the valve into service in a controlled manner to protect the system from damaging over-
pressure.

installed sensing line, and directs pressure into and out of the cover chamber of the 3-way Accelerator Pilot. When the cover of the Accelerator 
Pilot is pressurized, the main valve cover chamber is vented downstream, causing the valve to open. When the cover of the Accelerator Pilot is 
de-pressurized, the main valve cover chamber is connected to upstream pressure, causing the valve to close drip tight.

As water level decreases, static tank head pressure falls below the adjustable setpoint of the Altitude Pilot, causing it to pressurize the cover of 
the Accelerator Pilot, opening the valve. As water level increases, static tank head exceeds the adjustable setpoint of the Altitude Pilot, causing 
it to depressurize the cover of the Accelerator Pilot, closing the valve drip tight. Valve opening and closing speeds are separately adjustable. 
The Position Indicator with Air Bleed Petcock allow for visual indication of valve position, and allows easy venting of air entrapped in the main 
valve cover chamber.

The normally closed sustaining pilot remains open when upstream pressure is above the adjustable setpoint, and modulates toward a closed 
position if upstream pressure falls below the setpoint. As the sustaining pilot closes, fluid is directed into the main valve cover chamber through 
the integral orifice of the Accelerator Pilot, allowing the valve to modulate toward a closed position, raising upstream pressure. Normal tank fill 
operation resumes when upstream pressure is above the sustaining pilot setpoint.

Specify Tank height PRIOR to ordering.

1 – Main Valve (M100 – Single Chamber)

2 – Model 22 Accelerator Control 

3 – Altitude Control 

4 – Check Valve

5 – Pressure Sustaining Control

6 – Adjustable Closing Speed
7 – Adjustable Opening Speed

P – Position Indicator

X – Isolation Cocks 

Installation

LFM127-8 (Globe) One-Way Flow Altitude Control Valve with 
Pressure Sustaining Feature

2          IOM-ACV-127-8_6127-8 2115 

EDP# 1917065 

© 2021 Watts

Summary of Contents for LFM127-8

Page 1: ...on 2 Setting the Altitude 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 ...

Page 2: ...lowing instructions on Technical Bulletin Start up of an automatic control valve requires that proper procedures be followed Time must be allowed for the valve to react to adjustments and the system to stabilize The objective is to bring the valve into service in a controlled manner to protect the system from damaging over pressure installed sensing line and directs pressure into and out of the co...

Page 3: ...wly open the valve See Figure 1 STEP 3 Pressure the line by opening the upstream isolation valve slowly Air is vented through the air bleed valve Tighten the fitting when liquid begins to vent See Figure 1 Repeat the process until no air is trapped in the system Globe Angle Size in 11 4 11 2 2 21 2 3 4 6 8 10 12 14 16 20 24 A in 16 16 20 22 22 24 32 34 38 44 48 52 56 56 B in 10 10 12 14 14 16 24 2...

Page 4: ...r of the main valve If recovery of pressure is slow upon increased downstream demand turn the adjustment screw OUT counterclockwise increasing the rate of opening See Figure 2B If recovery of downstream pressure is too quick as indicated in a rapid increase in pressure possibly higher than the desired set point turn the adjustment screw IN clockwise decreasing the rate of opening See Figure 2A STE...

Page 5: ...red setting STEP 10 Adjust the Sustaining Control screw IN clockwise until the inlet pressure begins to increase See Figure 4A or OUT counter clockwise See Figure 4B to decrease stopping at the desired pressure STEP 11 Allow pressure to stabilize STEP 12 Fine tune the sustaining setting as required as detailed in STEP 10 STEP 13 Open upstream isolation valve to return to normal operation IOM ACV 1...

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: ... 2 1 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...

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 6 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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