Imperial LD920 User manual

H2/N2 Tracer Gas Leak Detector
Detects 5% H2 in 95% Nitrogen
Tracer Gas
LD920
User Manual
Made in U.S.A.
LeakDetectors-LD920-UserManual.indd 1 12/7/16 2:26 PM

INTRODUCTION
The LD920 features a long life sensor technology that is designed to detect H2/N2
Tracer Gas mixture.
Our unique digital leak size indicator takes the guesswork out of whether to repair
a small leak. The digital display is independent from the audio alarm and sensitivity
level, allowing the precise pinpointing of the leak source.
When used with the H2/N2 Tracer Gas mixture, the LD920 will detect leak rates
less than 5 ppm. The 5%H2/ 95%N2 Tracer Gas mixture is consistent with the
teaching of EMC Directive 2014/30/EU for use with Low GWP Leak Detection
System Tracer Gas. The LD920 does not require rechargeable batteries.
FEATURES
• Unique numeric leak size Indicator
• Long life, stable sensor
• H2/N2 sensitivity <5 ppm
• Automatic calibration and reset to ambient
• Visual LED leak alarm near sensor
• 3 adjustable sensitivity levels
• Low battery indicator
• True mechanical pump
• Audio mute function
• Uses 4 AA alkaline batteries
• CE Certied
• Comfortable Sanoprene grip
• 2-year warranty includes sensor
• Made in USA
2
LeakDetectors-LD920-UserManual.indd 2 12/7/16 2:26 PM

OPERATING INSTRUCTIONS
1.TURN ON: Press the ON/OFF button once to turn on and again to turn off.
NOTE: Hold button down for approximately 1 second to turn unit off.
2.WARM UP: The detector automatically starts heating the sensor. During the
heating cycle, the digital leak size indicator will ash 0 and the detector will sound
a slow “beep”. Warm up time is usually less than 20 seconds.
3.READY: The detector is ready to begin searching for leaks when the ashing
0 stops and the green sensitivity LED turns on. The audio “beep” increases in
frequency and the probe LED begins to blink steadily.
4.SEARCHING: When searching for leaks, move the sensor tip along A/C lines
and ttings no further away than 0.4 in. (9.5 mm) and no faster than 3 in./sec.
(75 mm/sec.) If the detector alarms, make smaller sweeps back and forth until the
leak source can be pin pointed. NOTE: The LD920 only responds to changes in leak
concentration. The alarm will re-set automatically if the sensor tip is held at the leak
source. If the leak detector has been out of use for an extended period, weeks or
months, the following action is recommended. Power on the instrument and allow it
to come out of warm up. Then run it with the sensitivity level in the Hi (high) position
for several minutes before testing it with the Leak Test Vial. This action will guarantee
that the sensor is fully conditioned for maximum response to tracer gas.
Digital Leak Size Indicator
Low Battery Indicator
Sensitivity Level Indicators
Audio Mute & Sensitivity Level Selectors
Power On/Off
LD920 CONTROL PANEL
3
LeakDetectors-LD920-UserManual.indd 3 12/7/16 2:26 PM

LEAK SIZE INDICATOR
The digital leak size indicator remains off normally but once a leak is detected,
a number from 1-9 will be displayed for all H2/N2 tracer gas regardless of the
sensitivity setting.
The number will continue to increase or decrease depending on the amount of
tracer gas sensed. The maximum value will be displayed once the leak source has
been located. The table below can be used to approximate the size of leak:
Maximum # Approx. Leak Size Approx. Leak Size
Displayed (oz/yr) (g/yr)
1 -3 < 0.1 <3
4-6 0.1 to 0.5 3 to 14
7-9 >0.5 >14
LOW BATTERY INDICATOR
Replace the 4 AA Alkaline batteries when the red LED on the control panel is lit.
Follow battery installation instructions under Maintenance section.
AUDIO MUTE FUNCTION
To silence or mute the audio beep and alarm signal, press the MUTE button.
To restore the audio sound, press the MUTE button again. (Note: a few seconds
is required to restore sound if the mute button is pressed in rapid succession.)
4
LeakDetectors-LD920-UserManual.indd 4 12/7/16 2:26 PM

ADJUSTING SENSITIVITY LEVELS
The leak detector will default to the NORM sensitivity level automatically once the
unit comes out of the warm up cycle and the green LED will turn on.
To change sensitivity levels, press the SENS once for HI sensitivity (red LED will
turn on) and again for LO sensitivity (yellow LED will turn on).
LEAK TEST VIAL
The leak detector includes a Leak Test Vial that allows the user to make sure the
detector is performing properly. To test:
1.Remove the colored label dot in the center of the screw cap to expose the
vent hole in the top of the screw cap. (see g. below).
2.Turn on the leak detector and allow the instrument to complete the warm
up cycle.
3. Place the sensor close to the small hole in the top of the Leak Test Vial.
The beep rate should increase and the Digital Leak Size Indicator should display a
number from 3-6 indicating that the sensor and the electronics are working properly.
NOTE: Replace the Test Vial back in the nylon bag when not in use to extend the
shelf life. Replace Test Vial when the green color is less than ¼ full or at the time of
the expiration date.
Remove label dot over
vent hole before testing
Vial cap with vent hole
Expiration date on label
5
LeakDetectors-LD920-UserManual.indd 5 12/7/16 2:26 PM

BATTERY MAINTENANCE
Install Batteries: Remove screw located at rear end of unit and pull down
hinged battery door to open as shown. Always insert all four batteries into the
battery compartment in the same direction. Note: polarity mark on the inside of the
battery door for proper battery orientation.
SENSOR MAINTENANCE
Replace Filter: Unscrew sensor tip as shown to replace lter. Replace lter
whenever it becomes visibly dirty or every 2 to 3 months depending on use.
Replace Sensor: Remove sensor by pulling out of socket. Install the new sensor
by aligning the Keyway notch in sensor cover with the raised keyway on sensor
socket holder (see gure below).
Note: Do not force sensor into socket. Misalignment can damage the sensor pins.
IMPORTANT: The instrument’s software is designed to alert the user if the sensor is dislodged or
defective. If the sensor is not fully inserted into the six-pin socket, or if it is defective, the instrument will not come
out of the “Warm Up” mode for proper operation when the power button is turned on. Additionally, if the instrument
becomes unstable during its operation, it is an indication that the sensor may be defective or dislodged.
Unscrew tip to
replace lter
Filter Push straight on (do not
twist) to install sensor
Pull straight out (do not
twist) to remove sensor
Keyway alignment
Polarity mark
6
LeakDetectors-LD920-UserManual.indd 6 12/7/16 2:26 PM

PRODUCT SPECIFICATIONS
Model # LD920
Name Leak Detector, H2/N2 Tracer Gas
Sensitivity < 5 ppm or 2 g/yr R134a equivalent
Sensor Life > 300 hours
Response Time Instantaneous
Power Supply 4 AA Alkaline batteries
Battery Life 4-6 hours continuous
Warm up time < 20 seconds
Probe length 17 inches (43.8cm)
Numerical Display 7 segment digital display (1 to 9)
Weight, lbs. 1.5 lbs. (0.68kg)
Warranty 2 years (includes sensor)
TRACER GAS DETECTION
Tracer Gas consists of a non-toxic, non-ammable, environmentally friendly (non-
polluting) mixture of 5% Hydrogen and 95% Nitrogen. For this reason, the Tracer
Gas can be released into the environment after the leak detection procedure is
completed. The 5%H2/95%N2 Tracer Gas mixture is consistent with the teaching
of EMC Directive 2014/30/EU for use with Low GWP Leak Detection System
Tracer Gas.
The LD920 detects the Hydrogen component of the tracer and because Hydrogen
molecules are so small, it is an ideal gas for leak detection.
The Tracer Gas is charged into an empty system at a pressure of approximately
75 psi (5bar). As Hydrogen is lighter than air, always probe slightly above the
suspected leak area. Once the source of the leak is located and repaired,
the Tracer Gas can be released and the system can be recharged again with
refrigerant. A nal check should be performed using a certied refrigerant gas leak
detector such as the Imperial LD900.
NOTE: Run engine with air conditioner on briey to properly distribute the
H2/N2 Tracer Gas.
7
LeakDetectors-LD920-UserManual.indd 7 12/7/16 2:26 PM

WARRANTY
The LD920 H2/N2 Tracer Gas Leak Detector is warranted to be free of
defects in materials and workmanship for a period of two years from the
date of purchase. This warranty applies to all repairable instruments that
have not been tampered with or damaged through improper use including
unauthorized opening of the unit. Tools should be returned to the buyer’s
place of purchase.
SERVICE/TECHNICAL QUESTIONS
CALL TOLL FREE: 888.467.8665
30333 Emerald Valley Pkwy. • Glenwillow, Ohio 44139 • 888.467.8665
REPLACEMENT PARTS
Item Part Number
H2/N2 Sensor with Sensor Tip and Filter S77704
Sensor Filters (5 pack) S77695
Leak Test Vial S77705
Parts Kit (includes H2/N2 sensor with sensor tip, test vial, & lter kit) S77706
Carrying Case S77707
Sensor Tip with Filter S77698
www.imperial-tools.com
[email protected]
LeakDetectors-LD920-UserManual.indd 1 12/7/16 2:26 PM