Swan Analytical Instruments AMI Silitrace Ultra User manual

AMI Silitrace Ultra
Version 6.20 and higher
A-96.250.831 / 070319
Operator’s Manual

© 2016, SWAN ANALYTISCHE INSTRUMENTE AG, Switzerland, all rights reserved
subject to change without notice.
Customer Support
SWAN and its representatives maintain a fully trained staff of technical specialists
around the world. For any technical question, contact your nearest
SWAN representative, or the manufacturer:
SWAN ANALYTISCHE INSTRUMENTE AG
Studbachstrasse 13
8340 Hinwil
Switzerland
Internet: www.swan.ch
E-mail: [email protected]
Document Status
Title: AMI Silitrace Ultra Operator’s Manual
ID: A-96.250.831
Revision Issue
00 June 2016 First Edition

AMI Silitrace Ultra
A-96.250.831 / 070319 1
Table of Contents
1. Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Warning Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2. General Safety Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1. Description of the System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2. Instrument Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3. Instrument Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3. Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1. Installation Checklist. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2. Assemble the Concentrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3. Mounting of Instrument Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.4. Connect Sample and Waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.5. Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.5.1 Connection Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.5.2 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.6. Relay Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.6.1 Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.6.2 Alarm Relay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.6.3 Relay 1 and 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.7. Signal Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.7.1 Signal Output 1 and 2 (current outputs) . . . . . . . . . . . . . . . . . . 29
3.8. Interface Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.8.1 Signal Output 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.8.2 Profibus, Modbus Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.8.3 HART Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.8.4 USB Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4. Instrument Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.1. Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2. Prepare reagents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.3. Prepare Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.4. Switch on Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.5. Adjust Sample Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.6. Activate the Peristaltic pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.7. Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.8. Run-in period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.9. Final Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

2A-96.250.831 / 070319
AMI Silitrace Ultra
5. Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.1. Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.2. Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.3. Software Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.4. Changing Parameters and values. . . . . . . . . . . . . . . . . . . . . . . . . 44
6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
6.1. Maintenance Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
6.2. Stop of Operation for Maintenance. . . . . . . . . . . . . . . . . . . . . . . . 45
6.3 Refill or replace Reagents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.4 Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.5 Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.6. Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.7. Zero. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.8. Replace the Pump Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.9. Fill system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.10. Clean the Photometer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.11. Longer Stop of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
7. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
7.1. Error List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
7.2. Troubleshooting List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.3. Replace the Reaction Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.4. Replace the 6-Way Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
7.5. Replace the Cuvette . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
7.6. Replace the Reagent Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7.7. Cleaning the solenoid valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
7.8. Opening the peristaltic pump housing. . . . . . . . . . . . . . . . . . . . . . 71
7.9. Replacing Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8. Program Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.1. Messages (Main Menu 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
8.2. Diagnostics (Main Menu 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
8.3. Maintenance (Main Menu 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
8.4. Operation (Main Menu 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
8.5. Installation (Main Menu 5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
9. Program List and Explanations. . . . . . . . . . . . . . . . . . . . . . . . . 79
1 Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
2 Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
4 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

AMI Silitrace Ultra
A-96.250.831 / 070319 3
5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
10. Safety Data sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
11. Default Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
12. Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
13. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

4A-96.250.831 / 070319
AMI Silitrace Ultra
Safety Instructions
AMI Silitrace Ultra - Operator’s Manual
This document describes the main steps for instrument setup, oper-
ation and maintenance.
1. Safety Instructions
General The instructions included in this section explain the potential risks
associated with instrument operation and provide important safety
practices designed to minimize these risks.
If you carefully follow the information contained in this section, you
can protect yourself from hazards and create a safer work environ-
ment.
More safety instructions are given throughout this manual, at the
respective locations where observation is most important.
Strictly follow all safety instructions in this publication.
Target
audience
Operator: Qualified person who uses the equipment for its intended
purpose.
Instrument operation requires thorough knowledge of applications,
instrument functions and software program as well as all applicable
safety rules and regulations.
OM Location The AMI Operator’s Manual shall be kept in proximity of the instru-
ment.
Qualification,
Training
To be qualified for instrument installation and operation, you must:
read and understand the instructions in this manual as well as
the Material Safety Data Sheets.
know the relevant safety rules and regulations.

AMI Silitrace Ultra
Safety Instructions
A-96.250.831 / 070319 5
1.1. Warning Notices
The symbols used for safety-related notices have the following sig-
nificance:
DANGER
Your life or physical wellbeing are in serious danger if such
warnings are ignored.
Follow the prevention instructions carefully.
WARNING
Severe injuries or damage to the equipment can occur if such
warnings are ignored.
Follow the prevention instructions carefully.
CAUTION
Damage to the equipment, minor injury, malfunctions or incor-
rect process can be the consequence if such warnings are ig-
nored.
Follow the prevention instructions carefully.
Mandatory
Signs
The importance of the mandatory signs in this manual.
Safety goggles
Safety gloves

6A-96.250.831 / 070319
AMI Silitrace Ultra
Safety Instructions
Warning Signs The importance of the warning signs in this manual.
1.2. General Safety Regulations
Legal
Requirements
The user is responsible for proper system operation. All precau-
tions must be followed to ensure safe operation of the instrument.
Spare Parts
and
Disposables
Use only official SWAN spare parts and disposables. If other parts
are used during the normal warranty period, the manufacturer’s
warranty is voided.
Modifications Modifications and instrument upgrades shall only be carried out by
an authorized Service Technician. SWAN will not accept responsi-
bility for any claim resulting from unauthorized modification or alter-
ation.
Electrical shock hazard
Corrosive
Harmful to health
Flammable
Warning general
Attention general

AMI Silitrace Ultra
Safety Instructions
A-96.250.831 / 070319 7
WARNING
Risk of Electrical Shock
If proper operation is no longer possible, the instrument must be
disconnected from all power lines, and measures must be taken
to prevent inadvertent operation.
To prevent from electrical shock, always make sure that the
ground wire is connected.
Service shall be performed by authorized personnel only.
Whenever electronic service is required, disconnect instru-
ment power and power of devices connected to.
– relay 1,
– relay 2,
– alarm relay
WARNING
For safe instrument installation and operation you must read
and understand the instructions in this manual.
WARNING
Only SWAN trained and authorized personnel shall perform the
tasks described in this document.
Download
MSDS
The current Safety Data Sheets (SDS) for the above listed Re-
agents are available for downloading at www.swan.ch.

8A-96.250.831 / 070319
AMI Silitrace Ultra
Product Description
2. Product Description
2.1. Description of the System
Application
Range
The AMI Silitrace Ultra is a complete monitoring system for the au-
tomatic, continuous measurement of trace amounts of silica in ultra
pure water.
Measuring
Principle
Dissolved silica in water is concentrated with the use of a RO (re-
versed osmosis) membrane followed by a photometrical detection
of silica.
Photometrical
Detection of
Silica
The determination of silica is done by the photometric analysis of
molybdate blue at 815 nm.
Silica and ortho-phosphates react at low pH with ammonium mo-
lybdate to the yellow colored molybdosilic acid respectively molyb-
dophosphoric acid. The molybdophosphoric acid is destroyed with
oxalic acid before the molybdosilic acid is reduced with iron-(II)-am-
monium-sulfate to the heteropolyblue complex.
Especially the reaction speed of the first reaction step to the molyb-
dosilic acid is relatively slow. It is the most time consuming part of
the whole reaction. As the reaction speed increases with increasing
temperature, it is time saving to heat up the sample. The AMI Sili-
trace therefore uses a thermostatic reaction chamber with a con-
stant temperature of 45 °C.
At 45 °C the complete reaction only needs 150 s (2.5 min). Be-
cause the reaction time plays an important rule in the color devel-
opment, the pump speed is adjusted constantly. Due to the
automatic heating and reaction time regulation a very high preci-
sion is achieved.

AMI Silitrace Ultra
Product Description
A-96.250.831 / 070319 9
Concentrator
function
principle
The Carrcentrator acts as a mesh that holds back large molecules
such as silica and allows smaller molecules (water, Na, etc.) to
pass through. The membrane is rolled to obtain as many layers as
possible. Most of the water (permeate) flows through the mem-
brane and only a small part forms the concentrate. The permeate
and the concentrate leave the module via two separate outlets.
The separation of permeate and concentrate needs a high flow
rate. As a minimum 100 l/h at 2 bar must be provided to press the
water through the membrane.
The aim of this measurement is to detect the silica in the concen-
trate and calculate it back to the feed water. Three points must be
taken into account:
Concentration factor: Distribution ratio between the total flow
and the concentrate flow.
Separation efficiency: Constant factor of 90%.
Background: Silica reading of the permeate. This reading is
the sum of the silica
– which is in the reagents and
– which passes the membrane.
The background is measured daily, the efficiency is fixed and the
concentration factor is changed constantly by the flows.
A
B
C
D
Feed water
Spiral-wound RO module
RO membrane
Feed spacer
E
F
G
H
RO membrane
Product spacer
Permeate
Concentrate
ABACD
EFGH
G

10 A-96.250.831 / 070319
AMI Silitrace Ultra
Product Description
The silica reading on the display is calculated as follows:
Where
Fluidic The sample enters at the sample inlet [S] and flows through the
concentrator [Q]. The sample is split in a permeate and a concen-
trate outlet which are led to the flow cell high flow [J] (permeate)
and the flow cell low flow [I] (concentrate). The flow rate is mea-
sured with the flow meters attached to the flow cells [I] and [J].
The concentrate is connected to the 6-way valve [H] position 1, the
permeate to position 6. Excess sample overflows into the sample
outlet.
The peristaltic pump [O] sucks the concentrate from the 6-way
valve and pumps it into the reaction chamber [C]. The reaction
chamber is wrapped around a heating device. It has 4 inlets to al-
low dosing of the necessary reagents.
In the reaction chamber the sample is heated up to 45°C, eliminat-
ing temperature deviations of the sample. In a first step Ammoni-
ummolybdate [K] and sulfuric acid [L] are added, to form the
yellowish molybsilic acid and molybdophosphoric acid.
Afterwards the oxalic acid [M] is added to mask the molybdophos-
phoric complex. At last the reducing agent ammonium ferrous (II)
sulfate [N] is added. The color of the sample turns to blue. As silica
is only present in trace amounts, the blue color can not be seen.
Afterwards the colored sample flows into the thermostatic cuvette
[D] until it is filled completely. Now the intensity of the color is mea-
sured at 815 nm. The color development is proportional to the silica
concentration in the sample.
As the level of the sample in the cuvette increases, the sample
overflows into the siphon tube [F] and eventually the cuvette is
drained spontaneously through the siphon tube. The sample is led
via the aeration and drain tube [R] into the sample outlet.
Dosing, mixing and filling of the photometer are determined by the
rotating speed of the peristaltic pump [O]. This speed is adjusted
automatically and guarantees the correct timing of the measure-
ment.
Feed water concentration = Efficiency • reading Concentrate – reading Permeate (Blanc)
Concentration factor
Concentration factor = Efficiency • Total flow
Concertrate flow
Reading Concentrate = – Log
VConc
VZero
Reading Permeate = – Log VPerm
VZero

AMI Silitrace Ultra
Product Description
A-96.250.831 / 070319 11
12
1
7
6
543
2
1
03
12
1A
1B
1B
2
2
3
4
1
1A03
2
2 3 4
11
12
4
3
2
03
04
3 402
34
02
04
04
0114
01
11
11
05
05
04
A
B
C
D
E
F
G
H
I
J
K
L
M
N
S
T
U
O
P
Q
R
A
B
C
D
E
F
G
H
I
J
K
Standard bottle
Photometer module
Reaction chamber
Cuvette
Cuvette de-aeration
Sample outlet (siphon tube)
Inlet from reaction chamber
6-way valve
Flow cell low flow
Flow cell high flow
Reagent 1
L
M
N
O
P
Q
R
S
T
U
Reagent 2
Reagent 3
Reagent 4
Peristaltic pump
Zero calibration valve
Concentrator
Aeration and drain tube
Sample inlet
Permeate
Concentrate

12 A-96.250.831 / 070319
AMI Silitrace Ultra
Product Description
Signal
Outputs
Two signal outputs programmable for measured values (freely scal-
able, linear, bilinear, log) or as continuous control output (control
parameters programmable).
Current loop: 0/4–20 mA
Maximal burden: 510 Ohm
Third signal output available as an option. The third signal output
can be operated as a current source or as a current sink (selectable
via switch).
Relays Two potential-free contacts programmable as limit switches for
measuring values, controllers or timer for system cleaning with au-
tomatic hold function. Both contacts can be used as normally open
or normally closed.
Maximum load: 1 A/250 VAC
Alarm Relay One potential free contact.
Alternatively:
Open during normal operation, closed on error and loss of
power.
Closed during normal operation, open on error and loss of
power.
Summary alarm indication for programmable alarm values and in-
strument faults.
Input One input for potential-free contact to freeze the measuring value
or to interrupt control in automated installations (hold function or re-
mote-off).
Communica-
tion Interface
(optional)
USB Interface for logger download
Third signal output (can be used in parallel to the USB interface)
RS485 with Fieldbus protocol Modbus or Profibus DP
HART interface
Safety
Features
No data loss after power failure. All data is saved in non-volatile
memory.
Over voltage protection of in- and outputs.
Galvanic separation of measuring inputs and signal outputs.

AMI Silitrace Ultra
Product Description
A-96.250.831 / 070319 13
2.2. Instrument Specification
Power Supply Voltage:
Power consumption:
100–240 VAC (± 10%)
50/60 Hz (± 5%)
DC version not available
max. 50 VA
Transmitter
specifications
Electronics housing
Ambient temperature:
Limit range of operation:
Storage and transport:
Humidity:
Display:
Aluminium with a protection degree of
IP 66 / NEMA 4X
-10 to +50 °C
-25 to +65 °C
-30 to +85 °C
10–90% rel., non condensing
backlit LCD, 75 x 45 mm
Sample
requirements
Flow rate:
Temperature:
Inlet pressure:
Outlet pressure:
100 l/h
5 to 50 °C
2 to 20 bar
pressure free
On-site The analyzer site must permit connections to:
requirements Sample inlet:
Sample outlet:
Ambient temperature:
3/4“ NPT
Flexible Tube 15x20 mm
5 to 50 °C
Silica
measurement
Measuring range:
Reproducibility:
Cycle time:
0.005 ppb to 25 ppb
±0.005 ppb or ±5%, whichever is greater
3 min

14 A-96.250.831 / 070319
AMI Silitrace Ultra
Product Description
Dimensions Panel:
Panel dimensions:
Screws:
Weight:
stainless steel
400x850x150 mm
8 mm
30.0 kg
2L
2L
2L
2L
Exit Enter
Ozone Monitor
AMI SILITRACE
TraceSiO ProcessAnalyzer
2
1200 mm / 47¼”
1120 mm / 44”
400 mm / 15¾”
606 mm / 23.86”
640 mm / 25.20”
824 mm / 32.4”
850 mm / 33½”
4 x dia. 10 mm / /”

AMI Silitrace Ultra
Product Description
A-96.250.831 / 070319 15
2.3. Instrument Overview
A
B
C
D
E
F
G
H
I
J
Panel
Standard bottle
Solenoid valve
Photometer module
6-way valve
Flow regulating valve
Flow cell low flow
Flow meter
Flow cell high flow
Flow meter
K
L
M
N
O
P
Q
R
S
T
Sample inlet low flow
Sample inlet high flow
Sample outlet
Reagent 4
Reagent 3
Reagent 2
Reagent 1
Peristaltic pump
Transmitter
Concentrator
A
B
C
D
E
H
G
F
K
L
I
J
N
M
O
P
Q
R
S
T

16 A-96.250.831 / 070319
AMI Silitrace Ultra
Installation
3. Installation
3.1. Installation Checklist
Check Instrument’s specification must conform to the National Electri-
cal Code, all state and local codes, and all plant codes and stan-
dards for electrical equipment.
On site require-
ments
100–240 VAC (± 10%), 50/60 Hz (± 5%) power outlet with
ground connection and 50 VA.
Sample line with sufficient sample flow and pressure (see
Instrument Specification, p. 13).
Installation Assemble the Concentrator, p. 17
Mounting of Instrument Panel, p. 20
Connect Sample and Waste, p. 21
Electrical
Wiring
NOTICE: Do not switch on the Instrument until all electrical
connections are made.
Connect all external devices like limit switches, current loops
and pumps.
Electrical Connections, p. 22
Connect power cord, see Power Supply, p. 25.
Start-up Proceed according to Start-up Procedure, p. 32.

AMI Silitrace Ultra
Installation
A-96.250.831 / 070319 17
3.2. Assemble the Concentrator
The concentrator is delivered in the following parts:
1Insert the concentrator membrane [B] into the concentrator
housing [A].
 Consider the flow direction indicated on the membrane label.
The flow direction is from bottom to top.
2Mark the sample outlet on the concentrator housing.
A
B
C
D
E
Concentrator housing
Concentrator membrane
Tube set for high and
low flow
2 O-rings
2 covers
F
G
H
I
4 cover fixing plates with
4 fixing screws
Blind plug
Serto fitting for sample inlet
2 Hollow profiles with pipe
clamps and fixing screws
ABC E FGHID

18 A-96.250.831 / 070319
AMI Silitrace Ultra
Installation
3Put the O-ring [D] into the groove of the cover [E].
4Put the cover onto the concentrator housing [A].
5Put the cover fixing plates [F] into the grove of the concentrator
housing.
6Fix it with the screws, tighten it well.
7With the second cover, repeat steps 2 to 4 on the other side.
A
D
E
Concentrator housing
O-Ring
Cover
E
D
A
F