SGB DL Series User manual

Documentation
Pressure Leak Detector DL ..
Please read instructions prior to commencing any work
As of: 03/2020
Item no.: 603 022

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 2 -
Design Variations
The leak detectors in the DL series are available in different versions
that are described more precisely by the letters attached to them.
DL .. ELC P FC M LE/LG 8S
Up to 8 leak detection probes can be
connected to the leak detector to moni-
tor access chambers, sumps, etc.
Equipped with data transfer module (DTM) for
LOD service. Data is transferred via Ethernet
(LE) or GSM (LG).
"Manometer": The leak detector is equipped
with a digital pressure indicator in the housing
cover.
"Filter Control": The leak detector is equipped
with a dry filter monitoring system which issues a
separate signal when the dry material has been
used up.
"Protected": Leak detector version in a weather-pro-
tected housing (stainless steel).
"Economic Leak Control": Combined leak detector and
indicating unit. The leak detector is equipped with an
integrated manifold for connecting up to 6 tanks.
As this version is always weather-protected, the "P" is
omitted.
".." = Numerical value which stands for the alarm pressure
of the leak detector. The alarm pressures range from
50 mbar to 3000 mbar.
"Pressure leak detector": The leak detector operates with
overpressure towards the atmosphere.
DL Versions

02/03/2020 PRESSURE LEAK DETECTOR DL .. - 3 -
Table of Contents
1.General......................................................................................5
1.1Information........................................................................5
1.2Explanation of Symbols ....................................................5
1.3Limitation of Liability .........................................................5
1.4Copyright ..........................................................................5
1.5Warranty Conditions .........................................................6
1.6Customer Service .............................................................6
2.Safety ........................................................................................7
2.1Intended Use ....................................................................7
2.2Obligation of the Operating Company ..............................7
2.3Qualification......................................................................8
2.4Personal Protective Equipment (PPE)..............................8
2.5Fundamental Hazards ......................................................9
3.Technical Data........................................................................10
3.1General Data ..................................................................10
3.1.1DL 50 to DL 450..............................................................10
3.2Electrical Data.................................................................10
3.3Pneumatic Data (Requirements for Measuring Gauge)..10
3.4Switching Values ............................................................11
3.5Field of Application .........................................................12
4.Design and Function..............................................................13
4.1System Design................................................................13
4.2Normal Operating Condition ...........................................16
4.3Function in Case of Leaks ..............................................16
4.4Dry Filter .........................................................................17
4.5Overpressure Valve ........................................................18
4.6Displays and Controls.....................................................19
5.Mounting the System.............................................................21
5.1Basic Instructions............................................................21
5.2Leak Detector .................................................................21
5.3Dry Filter .........................................................................21
5.4Requirements for Pneumatic Connection Lines (Between
Leak Detector and Container).........................................22
5.5Completing Pneumatic Connections...............................22
5.6Electrical Connection ......................................................23
5.7Installation Examples and Block Diagrams.....................25
6.Commissioning ......................................................................29
6.1Tightness Test ................................................................29
6.2Commissioning the Leak Detector..................................29
7.Functional Check and Maintenance.....................................30
7.1General Information ........................................................30
7.2Maintenance ...................................................................30
7.3Functional Check ............................................................ 30
8.Alarm/Malfunction..................................................................35
8.1Alarm ..............................................................................35
8.2Malfunction .....................................................................35
8.3How to Behave ...............................................................35
Contents

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 4 -
9.Spare Parts .............................................................................35
10.Accessories...........................................................................35
11.Disassembly..........................................................................35
11.1Disassembly....................................................................35
11.2Disposal ..........................................................................35
12.Appendix ...............................................................................36
12.1Dimensions and Drilling Patterns....................................36
12.2Version 8S "Leak Detection Probes for Monitoring
Access and Monitoring Chambers".................................38
12.3EU Declaration of Conformity..........................................39
12.4Declaration of Performance (DoP)..................................40
12.5Declaration of Compliance of the Manufacturer (ÜHP)...40
12.6TÜV-Nord Certifications ..................................................41
Contents

02/03/2020 PRESSURE LEAK DETECTOR DL .. - 5 -
1. General
1.1 Information
These instructions provide important notes on using the DL leak de-
tector. The prerequisite for workplace safety is the adherence to all
safety and handling instructions specified in this manual.
Furthermore, any local regulations for prevention of accidents appli-
cable at the site of use of the leak detector and general safety instruc-
tions must be complied with.
1.2 Explanation of Symbols
In these instructions, warnings are marked with the adjacent symbol.
The signal word expresses the level of hazard.
DANGER:
Imminently hazardous situation which, if not avoided, will result in
death or serious injury.
WARNING:
Potentially hazardous situation which, if not avoided, could result in
death or serious injury.
CAUTION:
Potentially hazardous situation which, if not avoided, could result in
minor or moderate injury.
INFORMATION:
Highlights useful tips, recommendations, and information.
1.3 Limitation of Liability
All information and instructions in this documentation have been com-
piled considering the applicable standards and regulations, the state
of the art, and our longstanding experience.
SGB does not assume any liability in the case of:
Noncompliance with these instructions
Improper use
Use by unqualified personnel
Unauthorized modifications
Connection to systems not approved by SGB
1.4 Copyright
The contents, texts, drawings, images, and other representations are
copyrighted and subject to industrial property rights. Any misuse is
punishable.


General

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 6 -
1.5 Warranty Conditions
We provide warranty for the DL leak detector for a period of 24
months from the day of installation on site in accordance with our
General Terms & Conditions.
The maximum warranty period is 27 months from our date of sale.
Warranty is subject to submission of the functional/test report on ini-
tial commissioning by qualified personnel.
The serial number of the leak detector must be stated.
The obligation of warranty shall cease to exist in case of
- inadequate or improper installation
- unintended use
- modifications/repair works carried out without the manufacturer's
consent.
Our warranty does not include parts, which may be perished prema-
ture due to their consistence or category of usage (e.g. pumps,
valves, gaskets, etc.). Furthermore, we are not liable for defects or
corrosion damages caused by humid or inappropriate installation en-
vironments.
1.6 Customer Service
Our customer service is available for any inquiries.
For information on contacts please refer to our website www.sgb.de
or the label of the leak detector.
General

02/03/2020 PRESSURE LEAK DETECTOR DL .. - 7 -
2. Safety
2.1 Intended Use
Pressure leak detector for double-walled containers, where pres-
sure is maintained via a pump.
Connection of interstitial spaces only in the case of below-
ground interstitial spaces.
Components that can generate explosive vapors must be con-
tained within double-walled containers, tubs, or surface sealings
whose medium-side walls are permeation-tight.
Note/exclusion: If a permeation into the interstitial space that can
lead to formation of an explosive atmosphere in the interstitial
space occurs due to the stored material and the material composi-
tion of the inside container walls (e.g., in the case of double-walled
GRP tanks), the DL leak detector must NOT be used.
The DLG leak detector can be used as an alternative in this case.
Please familiarize yourself with this version!
The alarm pressure must be at least 30 mbar higher than any
pressure against the interstitial space (from inside and/or outside).
Grounding (if applicable) in accordance with applicable regula-
tions1.
The leak detection system is leak-proof according to the table in
section 7.3.5 of this documentation.
Leak detector installed outside of the explosive area.
Lead-throughs for the pneumatic hoses are sealed gas-tight.
Leak detector (electric) cannot be turned off.
2.2 Obligation of the Operating Company
The DL leak detector is used in a commercial environment. The oper-
ating company is therefore subject to statutory occupational safety
obligations.
In addition to the safety instructions in this documentation, all applica-
ble safety, accident prevention, and environmental regulations must
be adhered to. In particular:
- Compiling a risk assessment and implementing its results in a di-
rective
- Performing regular checks as to whether the directive is in compli-
ance with the current standards
- The directive includes information on how to react to an alarm that
might arise
- Arranging for an annual functional check
1For example, in accordance with EN 1127
WARNING!
Danger in
case of incom-
plete docu-
mentation
Safety

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 8 -
2.3 Qualification
The personnel must be capable of independently recognizing and
avoiding potential risks based on their qualifications.
Companies commissioning leak detectors should have completed rel-
evant training with SGB, through SGB, or through its authorized rep-
resentative.
National guidelines must be adhered to.
For Germany:
Technical service qualification for mounting, commissioning, and
maintenance of leak detection systems.
2.4 Personal Protective Equipment (PPE)
Personal protective equipment must be worn during work.
- Wear the necessary protective equipment for the work in question
- Note and comply with on-site PPE signs
Entry in the "Safety Book"
Wear HV vest
Wear safety footwear
Wear hard hat
Wear gloves – where necessary
Wear safety goggles – where necessary
2.4.1 Personal protective equipment for systems that may be subject to risk of explosion
The points listed here refer exclusively to safety when working with
systems that may be subject to risk of explosion.
If work is performed in areas in which an explosive atmosphere must
be expected, the minimum required equipment is as follows:
Suitable clothing (risk of electrostatic charge)
Suitable tools (in accordance with EN 1127)
WARNING!
Danger to humans
and the environ-
ment in the case
of inadequate
qualification

Safety

02/03/2020 PRESSURE LEAK DETECTOR DL .. - 9 -
Suitable combustible gas indicator calibrated to the existing vapor-
air mixture (work should be performed only at a concentration of
50 % below the lower explosion limit2)
Measuring equipment to determine the oxygen content of the air
(Ex/O meter)
2.5 Fundamental Hazards
DANGER
From electric current
When working on the leak detector, it must be disconnected from the
power supply unless stated otherwise in the documentation.
Comply with relevant regulations regarding electrical installation, ex-
plosion protection (e.g., EN 60 079-17), if necessary, and accident
prevention.
DANGER
From explosive vapor-air mixtures
Ensure there is no gas present prior to performing work
Comply with explosion regulations, e.g., German Ordinance on Indus-
trial Safety and Health (Betriebssicherheitsverordnung, BetrSichV)
(and/or directive 1999/92/EC and the laws of the respective member
states resulting therefrom) and/or others.
DANGER
From working in chambers
The leak detectors are mounted outside the access chambers. Pneu-
matic connection is usually performed inside the access chamber.
Therefore, the chamber must be entered in order to complete the
mounting process.
Before entering, the appropriate protective measures should be
taken. Ensure no gas is present and that sufficient oxygen is availa-
ble.
2Other countries' or companies' regulations may provide different percentages.
Safety

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 10 -
3. Technical Data
3.1 General Data
3.1.1 DL 50 to DL 450
Dimensions and drilling pattern see Appendix, section 12.1
Weight 2.3 kg
Storage temperature range -40°C to +70°C
Operating temperature range 0°C to +50°C
- DL .. P version -20°C to +50°C
Buzzer volume >70 dB(A) at a distance
of 1 m
Housing protection class, plastic IP 30
stainless steel IP 54
3.1.2 DL 590 to DL 3000
Dimensions and drilling pattern see Appendix, section 12.1
Weight 2.7 kg
Storage temperature range -40°C to +70°C
Operating temperature range 0°C to +50°C
- DL .. P version -40°C to +60°C
Buzzer volume >70 dB(A) at a distance of
1 m
Housing protection class, plastic IP 30
stainless steel IP 54
3.2 Electrical Data
3.2.1 DL 50 to DL 450
Power supply 230 V, 50 Hz
Input capacity (without external signal) 50 W
Terminals 5, 6, external signal 230 V, 50 Hz, max. 200 VA
min. 20 mA
Terminals 11, 12 (potential-free) max. 230 V, 50 Hz, 3 A
min. 6 V/10 mA
External fuse for leak detector max. 10 A
Overvoltage category 2
3.2.2 DL 590 to DL 3000
Power supply 100 to 240 V, 50/60 Hz
optional: 24 V DC
Input capacity (without external signal) 50 W
Terminals 5, 6, external signal 24 V DC; max. 300 mA
Terminals 11…13 (potential-free) DC≤25 W or AC≤50 VA
Terminals 17…19 (potential-free) DC≤25 W or AC≤50 VA
External fuse for leak detector max. 10 A
Overvoltage category 2
3.3 Pneumatic Data (Requirements for Measuring Gauge)
Nominal size min. 100
Class precision min. 1.6
End scale value suitable
Technical Data

02/03/2020 PRESSURE LEAK DETECTOR DL .. - 11 -
3.4 Switching Values
Type DL pTS [mbar] pAE [mbar] pPA [mbar] PÜDV13[mbar] pPRÜF [mbar]
50 20 > 50 < 100 170 20 200
100 70 > 100 < 150 220 20 250
230* 200 > 230 < 310 360 10 400
280** 250 > 280 < 330 360 10 400
290 260 > 290 < 350 420 20 450
325** 300 > 325 < 360 385 10 400
330 300 > 330 < 410 465 20 500
400 370 > 400 < 500 565 20 600
450 420 > 450 < 510 565 20 600
590 560 > 590 < 700 770 30 850
750 720 > 750 < 850 940 30 1000
1000 970 > 1000 < 1400 1590 50 1750
1100 1070 > 1100 < 1450 1650 70 1820
1500 1450 > 1500 < 1900 2100 50 2350
2000 1950 > 2000 < 2400 2650 50 3000
2300 2250 > 2300 < 2770 3100 100 3500
2500 2450 > 2500 < 2900 3200 50 3550
3000 2950 > 3000 < 3400 3750 50 4150
Special switching values agreed to by SGB and customers
The following abbreviations are used in the table:
pTS Maximum pressure on the tank floor, incl. overburden pressure
pAE Switching value "Alarm ON"; the alarm will be triggered at this pressure level at the latest
pPA Switching value "Pump OFF" (= operating pressure)
pÜDV1 Opening pressure for overpressure valve 1 (interstitial space)
pPRÜF Minimum test pressure of the interstitial space
* added to the table at a later date
** only for below-ground containers; values were added to the table at a later date
Supplement to the table:
pAA Switching value "Alarm OFF"; the alarm will be deactivated if this value is exceeded
The switching value "Alarm OFF" is approx. 15 mbar higher than the switching value "Alarm ON" for
pressure levels < 1000 and approx. 100 mbar higher for pressure levels > 1000
(pAA = pAE + ~15 mbar (pressure levels < 1000) ~ 100 mbar (pressure levels > 1000))
pPE Switching value "Pump ON"
The switching value "Refilling ON" is approx. 15 mbar lower than the switching value "Refilling OFF"
for pressure levels < 1000 and approx. 100 mbar lower for pressure levels > 1000.
(pPE = pPA - ~15 mbar (pressure levels < 1000) ~ 100 mbar (pressure levels > 1000))
3The table lists the opening pressure for overpressure protection at which the volume flow of the pump is diverted. The
operating pressure (initial opening) is lower.
Technical Data

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 12 -
3.5 Field of Application
3.5.1 Interstitial space requirements
Proof of pressure resistance of the interstitial space (see section
3.4 Switching Values, column "pPRÜF" minimum test pressure of
the interstitial space)
Proof of suitability of the interstitial space (for Germany: proof of
usability from construction authority)
Sufficient passage in the interstitial space
Tightness of the interstitial space according to this documentation
The number of interstitial spaces of below-ground containers to
be monitored depends on the total interstitial space volume. Ac-
cording to EN 13160, 8 m3may not be exceeded. To make it pos-
sible to test the tightness of the interstitial space, it is recom-
mended not to exceed 4 m3.
3.5.2 Containers/interstitial spaces
Below-ground and above-ground double-walled steel or plastic
containers, without leak detection liquid in the interstitial space, in
factory or on-site production design, whose interstitial space is
suitable for connection of a DL .. in accordance with section 3.4.
Below-ground and above-ground single-walled steel or plastic
containers with pressure-resistant leak protection lining or leak
protecting jacket, whose interstitial space is suitable for connec-
tion of a DL .. in accordance with section 3.4.
Double-walled collecting tubs or surface sealings, whose intersti-
tial space is suitable for connection of a DL .. in accordance with
section 3.4.
3.5.3 Stored material
Water-hazardous liquids, with consideration given to the following
points:
The leak detection medium (air) must not react with the stored
material.
Vapor-air mixtures, arising from
- the stored liquid,
- the stored liquid combined with air/humidity or condensation,
- the stored liquid combined with components (materials) with
which the liquid comes into contact
must be classifiable in gas group II A and II B as well as in tem-
perature code T1 to T3.
Attention must be paid to the permeation tightness of the inner
wall.
Technical Data

02/03/2020 PRESSURE LEAK DETECTOR DL ..
- 13 -
4. Design and Function
4.1 System Design
4.1.1 Plastic housing
Interior view with:
01 Signal lamp “alarm”, red
09 Signal lamp "operation", green (white)
17 Overpressure pump
20 Three-way valve in the pressure line
21 Three-way valve in the measuring line
62 Check valve
64 Dust filter
69 Buzzer
70 Overpressure valve (interstitial space)
71 "Mute" button
76 Main board
140 Contact for serial data transfer
Design and Function
17
09
62
01
71
69
76
70
20
21
64
140

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 14 -
4.1.2 Stainless steel housing for DL 50 to DL 450
Interior view with:
17 Overpressure pump
20 Three-way valve in the pressure line
21 Three-way valve in the measuring line
62 Check valve
64 Dust filter
69 Buzzer
70 Overpressure valve
75 Display board
76 Main board
164 Moisture sensor (optional)
Design and Function
17
69
70
21
20
76
64
75
62
164

02/03/2020 PRESSURE LEAK DETECTOR DL ..
- 15 -
4.1.3 Stainless steel housing for DL 590 to DL 3000
Interior view with:
17 Overpressure pump
20 Three-way valve in the pressure line
21 Three-way valve in the measuring line
62 Check valve
64 Dust filter
69 Buzzer
70 Overpressure valve
75 Display board
76 Main board
102 Pressure sensor
140 Contact for serial data transfer
141 Keypad terminal strip
144 Temperature switch, frost protection
Design and Function
75
62
69
76
102
21
140
141
144
17
70
20
64

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 16 -
The DL .. pressure leak detector monitors both walls of a container for
leaks. The monitoring pressure is so high that leaks are displayed be-
low or above the liquid level (stored material and groundwater) due to
pressure drops.
To build pressure, an integrated pump takes in external air through a
dry filter and forwards it to the interstitial space.
The dry filter will dry the external air to a relative humidity of approxi-
mately 10 %. Drying is necessary to prevent moisture or condensa-
tion accumulation in the interstitial space. Used dry filter fillings must
be regenerated or exchanged.
Note for devices with an alarm pressure > 590:
Values of less than 50 mbar or less than 0.73 PSI will not be dis-
played.
Values between 50 and 999 mbar will be displayed in mbar without
any decimal places.
Values from 1 bar are displayed in bar with two decimals and from
10 bar with one decimal.
Values in PSI are displayed with one or two decimals.
4.2 Normal Operating Condition
The pressure leak detector is connected with the interstitial space(s)
via the pressure and measuring lines. The overpressure generated by
the pressure generator is measured and controlled by a pressure
sensor.
When the operating pressure is reached (Refilling OFF), the pressure
generator shuts off. The pressure drops off slowly due to unavoidable
leaks in the leak detector system. When the "Refilling ON" switching
value is reached, the pressure generator will be turned on and the op-
erating pressure will be built up again.
Under normal operating conditions, the leak detector will move be-
tween these two pressure values, with short run times and longer idle
times, depending on the degree of impermeability and temperature
variations of the overall system.
4.3 Function in Case of Leaks
If a leak occurs below or above the liquid level or groundwater, leak
detection medium seeps out of the interstitial space. The pressure will
fall until the pressure generator is turned on to reestablish the operat-
ing pressure. If the volume flow exiting the leak is larger than the re-
filling output, the pressure in the system will fall even though the pres-
sure generator is activated.
An enlargement of the leak will lead to a further drop in pressure until
the alarm pressure is reached. This triggers the visual and audible
alarms.
Design and Function

02/03/2020 PRESSURE LEAK DETECTOR DL .. - 17 -
4.4 Dry Filter
The air supplied to the interstitial space is fed through a dry filter in
the suction line. The dry filter dries the air to about 10 % relative hu-
midity to avoid corrosion and condensation accumulation4in the inter-
stitial space.
The dry filter is designed for one year as long as it is used as in-
tended and no additional temperature variances occur.
A used dry filter, which is orange in the beginning, will become color-
less (or green). Exchange or regenerate used drying material immedi-
ately.
- For the FC option (FC = Filter Control/dry filter monitoring), see
section 4.4.1 Devices with FC
Dry filter for below-ground containers:
TF 180 (the larger dry filters can also be used)
Dry filter for above-ground containers:
Type Max. volume of the interstitial space with
TF 180 TF 200 TF 400 TF 600 TF 1200
DL 50
350 750 1400 2100 4800
DL 100
DL 230
DL 290 300 600 1100 1600 3700
DL 330
DL 400 250 520 1000 1500 3500
DL 450
DL 590 240 500 900 1350 3000
DL 750
DL 1000 210 400 750 1150 2600
DL 1100
DL 1500 150 300 550 800 1850
DL 2000
DL 2300 130 250 400 700 1600
DL 2500
DL 3000 110 230 350 600 1400
4Condensation accumulations in the interstitial space can result in an impermissible rise in pressure.
Design and Function


PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 18 -
4.4.1 Devices with FC (dry filter monitoring)
Function
There is a sensor installed in the pump suction line, between the
pump and the dry filter, which measures the moisture in the air that is
drawn in.
The increase in relative humidity when the dry material has been
used up is detected by the sensor. In the event of insufficient drying
capacity, the visual, audible, and potential-free signals will be trig-
gered.
The signal is indicated visually via alternate flashing of
- the two red alarm indicator lights (up to DL 450), or
- the red and yellow alarm indicator lights (DL 590 and above) The
potential-free signal is indicated at terminals 31 to 34:
31/32 Contact opens in the event of a signal
31/34 Contact closes in the event of a signal
Replacing the dry material
When a "Dry filter used up" signal is triggered, the dry material should
be replaced within a reasonable time.
The audible signal can be acknowledged by pressing the key briefly.
The visual and potential-free signals will continue.
The whole signal can be acknowledged by pressing the
"Acknowledge dry filter signal" key for longer (until the bottom LED
flashes). When the pump is next activated (or, if this function is per-
formed while the pump is running, after approx. 30 seconds), the sig-
nal will be triggered again if the residual moisture is too high.
Once the dry material has been replaced, the dry filter signal must be
acknowledged as described.
Usage limits
The following usage limits must be observed with regard to the dry
filter monitoring system:
1. The pump must run for at least 30 seconds in order to obtain a
meaningful measurement. During or after commissioning of the leak
detector, the time between pump ON and OFF should be measured
to establish whether this minimum run time is achieved.
2. It is not possible to obtain meaningful measurement results at low
temperatures (below 5°C). The measurement function is therefore de-
activated below 5°C.
4.5 Overpressure Valve
The overpressure valve installed in the pressure line protects the in-
terstitial space against impermissibly high overpressures (exceeding
of the test pressure). Impermissibly high overpressures can occur due
to:
Temperature increase resulting from environmental influences
(e.g., sunlight)
Temperature increase resulting from hot filling (contact the manu-
facturer, if necessary)
Design and Function

02/03/2020 PRESSURE LEAK DETECTOR DL ..
- 19 -
4.6 Displays and Controls
4.6.1 Display
Indicator
light
Operating condition Alarm condition Alarm, audible alarm acknowledged Probe alarm Probe alarm, acknowledged Malfunction
OPERA-
TION:
green
ON ON ON ON ON ON
ALARM:
red
OFF ON
FLASH-
ING OFF OFF ON
LED: yel-
low (red
for DL 50
to 450)
ON FLASH-
ING OFF
Not used or, with FC dry filter monitoring, the yellow and red LEDs
flash alternately
4.6.2 "Turn off audible alarm signal" function
Briefly press "Mute" button once; audible signal turns off, and the red
LED flashes.
Pressing the button again will turn the audible signal on.
This function is not available during normal operating conditions and
malfunctions.
4.6.3 "Testing the visual and audible alarm signal" function
Press and hold the "Mute" button (for about 10 seconds). The alarm
will be triggered until the key is released.
This inquiry is only possible if the pressure in the system has ex-
ceeded the "Alarm OFF" pressure.
4.6.4 "Tightness inquiry" function
Press and hold the "Mute" button until the signal lamp "Alarm" starts
flashing rapidly, then release it. A value for the tightness is indicated
as follows:
a) Without display: The signal lamp "Alarm" will flash between 0 and
10 times, or
b) With display (M): The numerical value will be displayed digitally.
This display disappears after 10 seconds and the current pressure in
the system is displayed again.
For the "Tightness inquiry" function, the leak detector must have per-
formed at least 1 automatic refilling interval in normal operating
Design and Function

PRESSURE LEAK DETECTOR DL .. 02/03/2020
- 20 -
conditions (i.e., without external filling/evacuation, e.g., by an installa-
tion pump) to achieve a valid statement.
This inquiry is recommended before performing a regular functional
check of a leak detector. In this way, it is possible to estimate immedi-
ately whether it is necessary to look for leaks.
Number of flash signals Assessment of tightness
0 Very tight
1 to 3 Tight
4 to 6 Sufficiently tight
7 to 8 Maintenance recommended
9 to 10 Maintenance urgently recommended
The smaller the above value, the tighter the system. The significance
of this value also depends on temperature fluctuations and should
thus be considered a reference point.
4.6.5 "Acknowledge dry filter signal" function (only if FC filter monitoring is present)
Briefly press the "Acknowledge dry filter signal" key to shut off the au-
dible signal. The visual signal (alternate flashing of the red and yellow
LEDs) continues.
To reset the dry filter signal completely, press and hold the key until
an audible signal sounds.
4.6.6 Zero-point adjustment5
Turn three-way valve 21 90° clockwise from the operating position.
The alarm is triggered and the pump runs.
Press and hold the "Mute" button until the signal lamp “Alarm” starts
flashing rapidly (approx. 5 seconds), then release the button and
press and release it again.
The zero-point adjustment is confirmed with a visual and audible sig-
nal (3x).
Return three-way valve 21 to the operating position.
A repetition of the zero-point adjustment is not possible until the oper-
ating pressure has been built up.
5Function only available for DL 50 to DL 450
Design and Function

21
20
2120
21
20