Dover Wayne Helix WM048523 User manual

Service Manual
Wayne Helix™ Fuel Dispensers
WM048523
Rev 08
AE

Read this manual before starting any installation, service, or maintenance work
Fuel dispensers contain both electrical components and a hazardous, flammable and potentially
explosive fuel. Failure to follow the below precautions and the Warning and Caution instructions
in this manual may result in serious injury. In addition, it is your responsibility to follow all rules,
codes, regulations, and laws that apply to your location and type of work being performed.
Safety precautions
Make sure that ALL power to the dispenser is turned OFF before opening the cabinet or starting
work. Physically lock, restrict access to, and/or tag the circuit breakers you turn off. In addition,
be sure to trip (close) all emergency valves under the dispenser (if installed) BEFORE you begin.
Make sure that you locate the facility’s emergency shut-off button, and know how to turn OFF
power to the dispenser and submersible pumps (if any) in an emergency.
Never allow a leaking pump to run! Use appropriate measures to clean up any fuel on the fore-
court, and ensure that any leaks or issues that could cause a leak are attended to and repaired
immediately.
Indicators and notations
Note!
Indicates extra information or tip.
NOTICE!
Highlights an essential element of a procedure to
help ensure accuracy, completeness, and appropriate
performance.
CAUTION!
Indicates a potentially hazardous situation, which if
not avoided, could result in personal (non-lethal) in-
jury or equipment damage.
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WARNING!
INDICATES A POTENTIALLY HAZARDOUS SITUA-
TION, WHICH, IF NOT AVOIDED COULD RESULT
IN DEATH OR SERIOUS INJURY.
DANGER!
INDICATES A HAZARDOUS SITUATION, WHICH,
IF NOT AVOIDED, WILL RESULT IN DEATH OR
SERIOUS INJURY.
Note!
The graphics and pictures of dispensers contained in this manual may not be representative of
your actual dispenser(s).
Maintenance Note
The Ex dispensers or other Ex-materials designed and manufactured by Dover Fueling Solution
(“DFS”) are fully compliant with the applicable EU directives and harmonised standards (refer
to EU DoC for the list of applicable standards).
As with any material, the equipment supplied by DFS needs to be installed, maintained, inspected,
or repaired as recommended by DFS and/or suppliers of individual components associated with
the equipment.
Any installation, repair, maintenance, modification, etc. should only be conducted by approved
DFS maintenance partners or recommended partners of authorised DFS distributors and sales
channel partners.
The aforementioned equipment is subject to the following, which actions are only permitted to
be carried out by authorised and trained personnel:
1. Installation and commissioning
2. Regular periodic inspections, including metrology and vapour recovery.
3. Any required maintenance
4. Any repair or modification
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The instructions for installation and maintenance are contained within the corresponding DFS
manuals and must be adhered to. Approved replacement parts are listed in the DFS parts
manual. Failure to follow the contents of any of these manuals may invalidate warranty and result
in regulatory breaches and potential liability issues.
Dispenser owners, installers and qualified service technicians should be aware of local (coun-
try/region-specific) guidelines for inspection, maintenance and/or repair of equipment on filling
stations. It is the responsibility of these owners, installers and maintainers to check all relevant
information and to observe mandatory guidelines to ensure the safety of the filling station.
Installations, inspections, maintenance and repair shall be performed in accordance with the
following non-exhaustive list of standards:
For Ex-approved electrical equipment:
• EN 60079-14, Explosive atmospheres - Part 14: Electrical installations design, selection and
erection
• EN 60079-17, Explosive atmospheres - Part 17: Electrical installations inspection and mainte-
nance
• EN 60079-19, Explosive atmospheres - Part 19: Equipment repair, overhaul and reclamation
• IEC/IEEE 60079-30-2, Explosive atmospheres - Part 30-2: Electrical resistance trace heating
- Application guide for design, installation and maintenance
For non-electrical Ex-approved equipment:
• NPR-CEN/TR 16793, Guide for the selection, application and use of flame arresters
Before commencing dispenser-related work; installers, inspectors, operators and qualified repair
technicians need to be aware of any component-specific safety, maintenance and inspection
characteristics associated with the work they are performing.
The owner of the equipment is responsible to ensure that all required periodic checks on Ex-
components are performed. Some Ex-components require special measures to be taken for
maintenance, e.g. some ex-components may require a check within the first 3 months of operating
and additionally require an annual check by the owner.
Periodic verification of earthing and bonding during installation and maintenance periods shall
be put in place by the equipment owner, following national guidance.
As always, the latest edition of above standards must be verified and their compatibility with the
materials installed checked before issuing an inspection & maintenance program for each dis-
penser. It is evident that the ATEX protection modes of each component will influence the
generic maintenance program of any dispensers.
The equipment owner has the ultimate obligation for each site’s compliance with EN 13617 (or
any successor standard) and all building and safety codes and taking appropriate safety measures
in accordance with industry best practices. Where required, component manuals can be provided
to you upon request from the component manufacturer. DFS shall not be responsible for the
design or installation of safety measures not included as a component of the products; including,
without limitation, leak containment, traffic, control structures, emergency stop buttons, shear or
impact valves, or other fire suppression devices. Equipment owners acknowledge that the entire
use, management, and performance of the equipment remains solely with the equipment owner.
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Table of Contents
71 Introduction ...............................................................................................................
71.1 Features .......................................................................................................
81.2 Unlocking the Bezel ......................................................................................
91.3 Payment Terminal .........................................................................................
91.4 Bezel Latches ...............................................................................................
111.5 Service Position ............................................................................................
121.6 Non-Payment Bezel .....................................................................................
132 Hydraulics .................................................................................................................
132.1 Triple Bump Product Tubes ..........................................................................
142.2 Filter and Strainer Remotes .........................................................................
152.3 Strainer and Filter Suction Pumps ................................................................
152.4 Proportional Flow Control Valve ...................................................................
162.4.1 No Flow - Flow Control Valve Off ............................................................................
162.4.2 Slow Flow - Flow Control Valve On .........................................................................
162.4.3 Full Regulated Flow - Flow Control Valve On ..........................................................
182.5 iMeter and Xflo .............................................................................................
182.5.1 Check and Pressure Relief Valve ............................................................................
192.6 Hose Outlet Casting and Retainer Clip ........................................................
212.7 Vapour Recovery - IEC .................................................................................
212.7.1 Extracts from "0544100100L02-V001_EN1608_Dürr VR pump manual" ...............
222.8 Additive - IEC ................................................................................................
222.8.1 Startup, priming and purging of the additive system ...............................................
252.8.2 Adjusting of additive pump pressure .......................................................................
252.8.3 Calibration of additive system ..................................................................................
263 Electronics ................................................................................................................
273.1 Dispenser Connection Board .......................................................................
273.2 Dispenser Power On/Off Switch ...................................................................
273.3 Heater/Fan ....................................................................................................
273.4 Sales Volume and Unit Price Displays .........................................................
283.5 Nozzle Switch Interface Board .....................................................................
283.6 Nozzle Switch Converter Board ...................................................................
283.7 ISB Module ...................................................................................................
283.8 Temp Comp Module and TTL/CAN Converter .............................................
293.9 WIP ...............................................................................................................
304 Board Layout and Connector Descriptions ...............................................................
314.1 iGEM Computer Board .................................................................................
374.2 iGEM Board NA ............................................................................................
384.3 iGEM Board IEC ...........................................................................................
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394.4 iX R2 Board ..................................................................................................
414.5 Nozzle Switch Interface Board .....................................................................
414.6 Nozzle Switch Converter Board ...................................................................
424.7 Temperature Module (Temp Comp) ..............................................................
424.8 TTL / CAN Converter Board .........................................................................
434.9 ISB Board .....................................................................................................
464.10 Dispenser Connection Board - Remote Models NA .....................................
484.11 Dispenser Connection Board - Suction Models NA ......................................
504.12 Dispenser Connection Board - Remote Models IEC ....................................
524.13 Dispenser Connection Board - Suction Models IEC .....................................
544.14 Dispenser Connection Board - Remote 1000 Models IEC ...........................
554.15 Dispenser Connection Boards - Metal Head Models IEC ............................
564.16 Sales Display and Controller Board Assembly Version 1 .............................
574.17 Sales Display and Controller Board Assembly Version 2 .............................
584.18 Unit Price Display Controller Board ..............................................................
594.19 Secure Payment Module (SPM) - Low Profile ..............................................
604.20 24V Power Supply ........................................................................................
614.21 Heater/Fan ....................................................................................................
624.22 WIP Pulser ....................................................................................................
624.23 VGA Backlight Driver Board .........................................................................
624.24 EM Totalizers ................................................................................................
634.25 Wayne Connect IP-485 ................................................................................
634.26 Vapour (Vapor) Recovery .............................................................................
644.27 Door Security Switch Board - Metal Head Models IEC ................................
654.28 VGA Softkeys - Metal Head Models - IEC ....................................................
664.29 Preset Keypad 15-button - Metal Head Models IEC ....................................
695 Parts and Tools Reference .......................................................................................
695.1 New and Existing Parts ................................................................................
746 Replacement Procedures .........................................................................................
776.1 iGEM Computer Board Replacement ...........................................................
786.2 Nozzle Switch Converter Board ...................................................................
796.3 Nozzle Switch Interface Board .....................................................................
806.4 ISB Assembly Replacement .........................................................................
826.5 Nozzle Boot, Switch, or Flipper Replacement ..............................................
846.5.1 Nozzle Boot - 6000 Models IEC ..............................................................................
856.6 WIP Replacement ........................................................................................
866.7 IEC Proportional Valve and Coil Replacement .............................................
886.8 NA Proportional Valve Replacement ............................................................
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896.9 Meter Replacement - Removing Meter from Base .......................................
926.9.1 Check valve replacement ........................................................................................
956.10 Product Tube Replacement - Using the Tube Removal Tool .......................
1006.11 Product Tube Replacement - Not Using the Tube Removal Tool .................
1046.12 Outlet Casting Replacement ........................................................................
1066.13 Unit Price, Control Board, and Glass Replacement .....................................
1066.13.1 UPD, Controller Board or Totalizer Replacement ....................................................
1106.13.2 Unit Price Display Glass Panel ................................................................................
1146.14 Sales Display and Glass Replacement ........................................................
1146.14.1 Sales Display Assembly ..........................................................................................
1156.14.2 Sales Display Glass Replacement ..........................................................................
1226.15 QVGA Display, Softkeys, and Glass Replacement ......................................
1226.15.1 QVGA Display .........................................................................................................
1246.15.2 Softkeys and Glass Replacement ...........................................................................
1276.16 VGA and Backlight Replacement .................................................................
1276.16.1 VGA Replacement ...................................................................................................
1316.16.2 Backlight Replacement ............................................................................................
1326.17 Dispenser Connection Board Replacement .................................................
1366.18 24V Power Supply Replacement ..................................................................
1376.19 Heater / Fan Replacement ...........................................................................
1386.20 Low Profile USB Printer Replacement .........................................................
1396.21 iX R2 Board Replacement ............................................................................
1406.22 SPM and Battery Replacement ....................................................................
1406.22.1 Battery Replacement ...............................................................................................
1426.22.2 SPM Replacement ...................................................................................................
1436.23 Card Reader Replacement ...........................................................................
1466.24 Wayne Connect Module Replacement .........................................................
1476.25 Hose Handling ..............................................................................................
1476.25.1 6000 C style models - IEC .......................................................................................
1667 iGEM Software Downloads - IEC version .................................................................
1677.1 Bootstrap Procedure ....................................................................................
1688 iGEM Software Downloads - NA version ..................................................................
1698.1 Bootstrap Procedure ....................................................................................
1709 Error Codes, Problem Symptoms and Solutions - NA ..............................................
1709.1 Error Codes and Solutions - NA ...................................................................
1769.2 Problem Symptoms and Solutions ...............................................................
17910 Error Codes and Descriptions - IEC .........................................................................
17910.1 Error/Event Classification .............................................................................
17910.2 Error/Event Types .........................................................................................
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18411 Suction Pumps .........................................................................................................
18411.1 Compact Pumping Unit ................................................................................
18511.2 By-pass (Relief) Valve Assembly .................................................................
18611.3 Float and Valve Seat Assembly ....................................................................
18611.4 Air Separation ...............................................................................................
18611.5 Testing the Suction Pumping System ...........................................................
18711.5.1 Vacuum Test ............................................................................................................
18811.5.2 Pressure Test ...........................................................................................................
18811.5.3 Adjusting the By-pass Pressure ..............................................................................
18911.6 Suction Pump Motors ...................................................................................
18911.7 Troubleshooting ............................................................................................
19011.8 Repair ...........................................................................................................
19011.8.1 Lapping the Pressure Relief Valve ..........................................................................
19111.8.2 Lapping the Pressure Relief Poppet Stem ..............................................................
19211.8.3 Strainer ....................................................................................................................
19311.8.4 Rebuilding the Pumping Unit ...................................................................................
19311.8.5 Replacing the Lip Seal .............................................................................................
19612 Small Pump 2000 Model Series ...............................................................................
19712.1 Sales/Vol and Unit Price Displays ................................................................
19812.2 Lower Electronics Enclosure (LEE) ..............................................................
20113 Meter Calibration Procedure .....................................................................................
20113.1 NA Procedures .............................................................................................
20413.2 IEC Procedures ............................................................................................
20514 Models with Metal Electronic Head - IEC .................................................................
20614.1 Bezel Components .......................................................................................
20714.2 Removing the Bezel .....................................................................................
21114.3 Replacement Procedures .............................................................................
21114.3.1 Display Glass and Speakers ...................................................................................
21514.3.2 VGA Display or Backlight ........................................................................................
22514.3.3 VGA Softkeys and Preset Keypad ...........................................................................
23014.3.4 Sales Volume Display ..............................................................................................
23114.3.5 R2 Board .................................................................................................................
23314.3.6 Secure Door Board ..................................................................................................
23414.3.7 VGA Backlight Driver Board ....................................................................................
23514.3.8 Fan ..........................................................................................................................
23514.3.9 EMT Totalizers .........................................................................................................
23714.4 Removing the Lower Covers and Vapor Vents .............................................
24115 Helix 6000 DEF, Extra Narrow Model Dispensers - IEC ...........................................
24915.1 Heater and Tank Replacement .....................................................................
25515.2 Pump Replacement ......................................................................................
25615.3 Motor Replacement ......................................................................................
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26015.4 iMeter Replacement .....................................................................................
26315.5 Hose Replacement .......................................................................................
27016 Helix LPG - IEC ........................................................................................................
27416.1 Degassing Unit Replacement .......................................................................
28516.2 Differential Valve Replacement ....................................................................
29016.3 Solenoid Valve Replacement .......................................................................
29316.4 Meter Replacement ......................................................................................
30216.5 Degassing Unit Filter Replacement ..............................................................
30317 Printer Maintenance .................................................................................................
30317.1 Printer Paper Specification ...........................................................................
30317.2 Thermal Characteristics ...............................................................................
30317.3 Thermal Response Range ...........................................................................
30417.4 Residual Particles .........................................................................................
30417.5 Loading Printer Paper ..................................................................................
30917.6 Clearing Paper Jams ....................................................................................
31218 iMeter2 Components Replacement Procedures ......................................................
31218.1 Proportional Valve ........................................................................................
31418.2 Check Valve Replacement ...........................................................................
31618.3 iMeter 2 Replacement ..................................................................................
32018.4 iMeter 2 Cylinder Cover O-ring Replacement ..............................................
32618.5 iMeter 2 WIP Replacement ..........................................................................
Appendices
327A iX Pay™ Secure Payment Configuration U.S. Version (Optional) ............................
328A.1 Initial Configuration Procedure .....................................................................
344B Valance Installation ...................................................................................................
348C Wiring Diagrams NA (North America) .......................................................................
349D Wiring Diagrams IEC ................................................................................................
350E Hydraulic Configurations - Helix 2000, 4000 & 5000 Model Dispensers ..................
356F TORX Kit ..................................................................................................................
357G IEC ATEX Information ..............................................................................................
359H NA UL Sub-pump Relay Information ........................................................................
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Table of Contents

1 Introduction
This manual contains detailed service information for Wayne Helix™ fuel dispensers. This
manual applies to Helix 1000, 2000, 4000 (narrow body), 5000 (wide body) and 6000 (C-style)
model series. The manual should be used for troubleshooting and repair purposes by Wayne
certified technicians only.
This is a global service manual used by technicians around the world servicing Helix dispensers.
"NA" in this manual refers to parts or procedures used specifically in North America. "IEC" in
this manual refers to parts or procedures used specifically in Europe and in countries adhering
to IEC and ATEX standards.
1.1 Features
Some of the features of Helix dispensers are listed below:
•Most current circuit design and functionality, with expansion capabilities for various types of
displays and future options
•New two-piece bezel
•Many of the outside components and bezel parts snap in place and do not require hardware
•Improved serviceability of hydraulic components — valves, meters, and outlet castings. Using
the new tube removal tool, there is no longer a need to use ladders when replacing product
tubes
•New filter/strainer casting and attached funnel to reduce fuel spills when changing filters
•Newly designed dual vapor barrier with a 1-1/2 inch space between the two barriers eliminates
need for lock nuts above and below the barrier. This makes changing valve coil/conduits
much easier. WIP cables and nozzle switch wires are no longer in a potted fitting and can be
replaced individually
•New power on/off switch located by the iGEM board shuts down power in the dispenser
•Easily replaceable nozzle boots
•Incorporates use of USB printer
The following sections in this manual give details on the new hydraulic and electronic components
used in Helix dispensers. The figures on the following pages show how to gain access to the
inside of the dispenser for service.
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1 Introduction

1.2 Unlocking the Bezel
Perform the following the steps to open the bezel and payment terminal for service.
1Unlock bezel U-frame shown in Fig 1.1, then raise the frame to the overhead position.
2Unlock Payment Terminal Drawer. See lock location in Fig 1.2.
3Locate the two latches, underneath the payment terminal, then firmly push up on latches and
pull out to unsnap. The latches are shown in detail in Fig 1.3.
4Continue to pull the drawer out into the service position as shown in Fig 1.4.
Latch
Lock
Latch
Figure 1.1: Unlocking the Bezel
Note!
The typical dispenser bezel with payment terminal is shown above. A typical non-payment bezel
is shown in Figure 1.5.
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1 Introduction

1.3 Payment Terminal
lock
payment terminal
Figure 1.2: Payment Terminal Drawer Lock
1.4 Bezel Latches
Locate latch behind PTS panel and push upward. The right side of the bezel is shown here for
clarity but there is a latch on both ends of the PTS panel. Push up on the tabs using one hand
on each end.
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1 Introduction

Figure 1.3: Latches Behind the Payment Terminal Bezel
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1 Introduction

1.5 Service Position
Figure 1.4: Helix Dispenser Service View
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1 Introduction

1.6 Non-Payment Bezel
A typical Non-payment bezel is shown below. See the procedure in the Small Pump section of
this manual to gain access for servicing the components in the upper section and in the Lower
Electronics Enclosure (LEE).
Sales Display
Panel
Preset/Options
Panel
LEE
Figure 1.5: Non-payment bezel
Figure 1.6: U-frame raised. Model with four sales displays.
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1 Introduction

2 Hydraulics
The hydraulic parts in the Helix dispenser are listed below. These basic parts are discussed in
detail in this section.
•Product Tubes
•Strainer and Filter (Remotes)
•Strainer and Filter (Suction Pumps)
•Proportional Flow Control Valve
•iMeter and WIP
•Check & Pressure Relief Valve
•Hose Outlet Casting
•Vapor (Vapour) Recovery
2.1 Triple Bump Product Tubes
Helix dispensers use triple bump product tubing between the proportional valve and the new
hose outlet casting. As with the double bump tube, the triple bump connection eliminates the
need to torque the compression fittings that were used on flare tubing. The triple bump tube,
along with a circular retainer in the hose outlet casting, eliminates the need for a retaining pin
at the outlet casting.
The triple bump tube and retaining pin are shown in Fig 2.1. When the tube is inserted into the
outlet or valve casting, the o-ring compresses and spreads across the space between the first
and second bumps, making a tight seal around the cylinder. The tube retaining pin at the valve
and the retaining clip at the hose outlet are inserted between the second and third bumps. The
tube retaining pin and clip secure the tube, but they also improve the seal by allowing some
flexibility as to exactly where the seal is made. The clip is shown in Figure 2.7.
Product tubes are 24 mm in diameter, which is slightly larger than the 7/8" tubes on previous
dispenser model series. The tubes have slightly larger outer diameter, but they also have a
larger inner diameter which allows for increased flow rate.
The valve castings are different on Helix dispensers, but only because of the increased distance
between the two holes for the new tube retaining pin. The valve castings are made from the
same material and have the same inner diameter as the valve castings on previous Wayne dis-
pensers. The valve castings will support 24 mm triple bump or 7/8" double bump tubes because
the outer diameter at the triple and double bump locations on the tubes are the same. Both Helix
series dispensers and current Wayne Ovation™ fuel dispensers use this newer valve casting
and retaining pin.
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2 Hydraulics

Figure 2.1: Triple Bump Tube and Retaining Pin
2.2 Filter and Strainer Remotes
The filter should be changed and the strainer cleaned on a regular basis. A dirty filter and
strainer may cause the dispenser to deliver fuel slowly. In some cases, this may appear to be a
more serious service related problem, when simply changing the filter and cleaning the strainer
is all that is required.
Before removing the filter, trip the shear valve and turn OFF the circuit breaker for the associated
submersible pump.
On Remote dispensers, the fuel filter is removed the same way an oil filter is removed from a
car engine. For Suction Pumps, see Section 11. As shown in Fig 2.2 for remotes, the new fuel
funnel catches any fuel that is spilled and properly drains it into a container. Place a container
under the funnel spout when changing the filter.
To install the new filter, first apply a film of oil to the gasket and hand turn until the gasket contacts
the base. Then tighten one half turn. Open the emergency shear valve, turn the submersible
circuit breaker ON and check for leaks. In new installations it may be necessary to change the
filter frequently in the first few days of operation in order to ensure proper operation.
The strainer is located inside the casting and held in place by the filter. Place a suitable container
below filter/strainer casting to catch product and sediment. Remove the filter and gently pull the
strainer out of the filter/strainer casting. Clean strainer screen of any debris. Reinstall strainer
and a new filter.
If the underground installation is new, it may be necessary to clean the strainer screen two or
three times the first few days of operation to remove debris and pipe dope. After this, occasional
cleaning of the strainer is all that should be required. The fuel filter should be changed whenever
the strainer is cleaned.
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2 Hydraulics

Filter
Spill Funnel
Strainer located
inside the casting
Coupling part
of iMeter base
Figure 2.2: Strainer Casting, Filter, and Spill Funnel
2.3 Strainer and Filter Suction Pumps
Refer to the Suction Pump section of this manual for details.
2.4 Proportional Flow Control Valve
The proportional flow control valve is a pilot-operated solenoid valve located between the meter
and the hose outlet. The valve performs two basic functions. It regulates the ratio of blended
feedstocks, and it controls the flow rate by limiting the maximum flow rate through a given hose.
The valve and coil are shown in Figures 2.3 and 2.4. The IEC and NA regions use the same
valve. The coils are slightly different in shape, but they are both ASCO coils and they operate
in much the same manner as described below.
The valve is controlled by a 24 VDC pulse width modulated (PWM) signal with discrete bursts
of current at a set frequency level. When the coil receives this signal, the pilot inside the operator
reacts to the changing magnetic field and moves up and down depending on the amount of
current through the coil. The position of the pilot relative to the pilot orifice in the piston controls
the amount of flow. Normally closed, the pilot opens by an amount proportional to the amount
of current sent to the valve coil. As the pilot raises off its seat, it reduces the pressure to the back
side of the piston causing it to lift off of its seat as well. The same applies to the valve closing.
In blender models, the piston follows the pilot back to the closed position as the current to the
coil is reduced. During a sale, the iGEM computer continually adjusts the current to the valves
based on the desired blend ratio of the two feedstocks and the maximum allowable flow rate. In
blenders, the high and low products remain separate until they are mixed at the hose outlet.
At the beginning of a sale, the coil is energized with a minimum current level, allowing slow
product flow to start. After a small amount of product is delivered, the coil is energized with more
current to initiate full regulated flow. For preset sales, the dispenser will switch back to slow flow
at a pre-determined point.
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2.4.1 No Flow - Flow Control Valve Off
Flow control valve “Off” or no flow occurs when the inlet to the valve is charged. But there is no
flow required from the particular valve as in the instance where a submersible pump motor is
running because another fueling point is being used. The pilot stays closed allowing pump
pressure to build on the back side of the piston, closing the outlet port.
2.4.2 Slow Flow - Flow Control Valve On
Flow control valve “On” slow flow occurs at the beginning of all sales, and again at the end of
preset sales. In this case the coil is energized with current bursts of shorter duration. This allows
the pilot to slightly move off its seat, allowing slow flow through the pilot orifice leading to the
valve outlet, but not relieving enough pressure to cause the piston to open.
2.4.3 Full Regulated Flow - Flow Control Valve On
Flow control valve “On” full regulated flow occurs during the main portion of all sales. At this
time, the coil is energized with bursts of current of longer duration, pulling the pilot further off it’s
seat, relieving the pressure balance, and allowing the piston to open by an amount relative to
the distance between pilot and the pilot orifice. The position of the pilot is constantly moving in
very small increments based on the signals sent from the computer relative to controlling a
specific blend ratio and/or maintaining a maximum flow rate of 38 lpm (10 gpm) through a hose.
As the computer senses the need to increase or decrease the amount of a particular feedstock,
it will send signals to the coil of longer (to open) or shorter (to close) duration. As a result, the
pilot moves up or down causing the piston to follow its movement and achieve the proper amount
of flow.
When the delivery is complete, the coil is de-energized, allowing the pilot to return to its closed
position. This allows pressure to build on the back side of the piston, forcing it to close and seal
the outlet port thereby stopping flow.
Coil
used in NA
Valve
Tube Retaining Pin
Conduit
Figure 2.3: Proportional Valve and Coil
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