Bacharach LS-20B User manual

CONTENTS
Page
CHECKING MATERIAL RECEIVED................................................... 2
DESCRIPTION ....................................................................................... 2
Components....................................................................................... 4
OPERATION........................................................................................... 5
Preparation for Operation ................................................................ 5
Applications....................................................................................... 6
Operational Procedure...................................................................... 7
PRINCIPLES OF OPERATION............................................................. 9
MAINTENANCE .................................................................................. 10
Relling Leak Standard ................................................................ 10
Replacing Leak Capillary ............................................................... 13
APPLICATION DATA .......................................................................... 14
RENEWAL PARTS ............................................................................... 16
SERVICE CENTERS............................................................................ 17
IM 11U4B1-01E
3rd editiion
3015-1942
Type LS-20B
Leak Standard
Printed in U.S.A. ® Registered Trademark

Type LS-20B Leak Standard
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WARRANTY
The Type LS-20B Leak Standard is warranted to be free from
defects in material or workmanship for a period of one year from the
date of purchase.
If your Leak Standard requires servicing because of any defects in
materials or workmanship, it will be serviced without charge. This
warranty does not extend to servicing or repairs resulting from mis-
handling, normal wear, or relling.
The sole obligation of the Bacharach, Inc. shall be limited to re-
pairing or replacing the Leak Standard or any part thereof, and in
no event shall Bacharach, Inc. be liable for special or consequential
damages.
CHECKING MATERIAL RECEIVED
The Type LS-20B Leak Standard, with accessories, is shipped in
one carton. Check to see that you have received all items (see Fig. 1).
Examine the Leak Standard immediately for any damage that may
have occurred in transit. If damage is found, a damage claim should
be led with the transportation company, and the nearest Bacharach
service center should be notied promptly.
DESCRIPTION
The Type LS-20B Leak Standard is a simple, accurate instrument
which expels a halogen compound gas, Refrigerant-12 or Refrigerant-
134a, through a glass capillary marked PROBE, to the atmosphere at
a known rate. This known rate is adjustable when using an LS-20B
Leak Standard. The Leak Standard is intended primarily for use with
Bacharach halogen-sensitive leak detectors.

Type LS-20B Leak Standard
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Description
Fig. 1. Type LS-20B Leak Standard and Accessories
Fig. 2. Type LS-20B, Outline Dimensions

Type LS-20B Leak Standard
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COMPONENTS
The Type LS-20B Leak Standard is a compact instrument consist-
ing of the following seven functional components (see Fig. 3):
1. A direct reading LEAK RATE gage (calibrated in ounces of R-12
or R-134a per year).
2. A PROBE tting in the center of which is a glass leak capillary.
A different capillary is used for each leak rate.
3. An INCREASE valve and control knob.
4. A DECREASE valve and control knob.
5. A VENT (with protective cap) for exhausting R-12 /R-134a gas.
6. A TANK for holding liquid R-12 /R-134a.
NOTE: The tank contains some R-12 / R-134a refrig-
erant when shipped from the factory.
7. A Reservior for holding R-12 / R-134a gas at a pressure corre-
sponding to the desired leak rate.
Fig. 3. Type LS-20B Leak Standard
INCREASE VALVE
CONTROL KNOB
DECREASE VALVE
CONTROL KNOB
PROBE
FITTING
VENT
FUSIBLE
PLUG
TANK
(LIQUID)
LEAK RATE
GAGE
CONNECTOR
TUBE ASM.
CAPILLARY
HOUSING
RESERVOIR
(REFRIGERANT GAS)

Type LS-20B Leak Standard
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OPERATION
PREPARATION FOR OPERATION
1. Remove the protective caps from the leak capillary in PROBE
tting and from the VENT.
2. To increase the leak rate, slowly turn the INCREASE valve
knob counterclockwise until the instrument’s LEAK RATE gage
pointer starts to move up scale. As the pointer approaches the
desired leak rate, gradually close the INCREASE valve so that
the pointer will stop at the desired leak rate. If the instrument
pointer continues to go up scale, this is an indication that the
INCREASE valve is not closed, make sure the INCREASE valve
is rmly closed.
CAUTION:
Avoid running the instrument pointer off scale. This
can subject the instrument to as much as 500%, over-
pressure. Although the unit can withstand the over-
load, repeated abuse may damage it.
3. To decrease the leak rate,
slowly turn the DECREASE
valve knob counterclockwise
until the instrument’s pointer
starts to move down scale. As
the pointer approaches the
desired leak rate, gradually
close the DECREASE valve so
that the pointer will stop at
the desired leak rate. If the instrument pointer continues to go
down scale, this is an indication that the DECREASE valve is
not closed. Make sure the DECREASE valve is rmly closed.
4. After increasing or decreasing the leak rate, be sure both valves
are closed by turning each knob fully clockwise.
5. After increasing or decreasing the leak rate and valves are
rmly closed, wait approximately one minute for the leak rate
to stabilize before calibrating your leak detector.
Operation

Type LS-20B Leak Standard
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NOTE: When the leak rate is being decreased, the
refrigerant gas is allowed to escape through the Vent to
atmosphere. During this operation it is best to remove
the Leak Standard from the test area. If this is not pos-
sible, attach the VENT TUBING to the vent and lead
the tubing out a window or to the oor.
6. The Leak Standard is now ready for use.
APPLICATIONS
The Leak Standard may be used in several ways:
• To check the operation and sensitivity of the leak detector:
The probe of the detector to be checked is moved past the
PROBE FITTING of the Leak Standard, which is set at the
maximum leak rate allowable for any single leak on the item
being leak tested. If an adequate signal is obtained, the leak
detector has sufcient sensitivity (or more) to detect this rate
of leak.
• To determine size of leaks: If the Leak Standard is set so that
the leak detector gives the same signal for the Leak Standard as for
the leak, the Leak Standard then indicates the size of the leak.
• To extend the useful life of the sensing element of the leak
detector: Users frequently replace the detector’s sensing ele-
ment long before the end of its useful life. A sensing element can
be used until it no longer responds to the desired setting of the
Leak Standard. Additionally, the Leak Standard permits use of
the lowest possible heater current to provide adequate leak de-
tector sensitivity. These practices increase sensor life and result
in reduced maintenance and lower replacement costs.
• To simplify establishment of leak-rate specications:
The Leak Standard makes feasible the establishment of leak-
rate specications and provides a uniform standard for calibrat-
ing leak detectors at each location of product inspection. This
assures agreement of all tests.
• To improve product quality: By calibrating leak detectors
with the Leaks Standard, it is now possible to locate and repair
all signicant leaks, thus assuring high quality work.

Type LS-20B Leak Standard
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OPERATIONAL PROCEDURE
CAUTION:
Never allow any grease or liquid to enter the LEAK
CAPILLARY, as it may plug or alter its leak rate.
When the Leak Standard is not in use, it is recom-
mended that the instrument pointer be set at half
scale, and that the PROTECTIVE CAPS be placed
over the VENT and LEAK CAPILLARY. This must be
done in order to prevent plugging of the capillary.
When unit or system contains 100% R-12 / R-134a
With the Leak Standard prepared for use as described under
PREPARATION FOR OPERATION on Page 5, proceed as follows:
1. Turn on your leak detector and allow it to warm-up for the time
prescribed in the applicable leak detector instruction manual.
NOTE: Before performing the following step, it is
necessary to blow your breath lightly over the LEAK
CAPILLARY on the Leak Standard — at a distance
of about 15 inches. This will eliminate any refriger-
ant that may have accumulated around the LEAK
CAPILLARY.
2. Pass the tip of the leak detector probe
past the PROBE tting on the Leak
Standard at a rate of about one inch
per second, so that the tip of the
probe just grazes the front circular
edge of the PROBE tting and passes
across the center of the PROBE t-
ting. (See Fig. 4.) DO NOT LET THE
LEAK DETECTOR PROBE TOUCH
THE GLASS CAPILLARY. If probe is
allowed to touch, YOU MAY BREAK
THE GLASS CAPILLARY.
Operation
Fig. 4. Checking
Sensitivity of Leak
Detector

Type LS-20B Leak Standard
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3. Repeat the above procedure, reducing or increasing the sensitiv-
ity of the leak detector each time, until the leak detector signal
is adequate.
4. Replace the protective cap on the LEAK CAPILLARY and pro-
ceed to probe the suspected leak area, following the procedure
outlined in the leak detector’s instruction manual.
A leak that gives the same leak signal as the Leak Standard is the
same size as indicated by the Leak Standard. A larger or smaller
signal indicates a larger or smaller leak, respectively.
If it is desired to determine the size of any leak that is located,
adjust the Leak Standard in 0.1 ounce increments (waiting approxi-
mately one minute after each change) until the signal caused by the
Leak Standard is the same as that caused by the leak. The Leak
Standard now indicates the size of the leak in question.
When unit or system contains less than 100% R-12 / R-134a
For this application the Leak Standard may be used to calibrate a
leak detector; however, a leak from the vessel (such as a tank, pipe,
or steam condenser), that produces the same leak signal as does the
Leak Standard, will have a total leak rate that is approximately in-
versely proportional to the percent R-12 / R-134a in the enclosure.
Example: with 10% Refrigerant-12 used in the enclosure and a
Leak Standard indication of 1.0 ounce per year, the leak rate is
1.0x10, or 10 ounces per year.

Type LS-20B Leak Standard
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PRINCIPLES OF OPERATION
The Type LS-20B Leak Standard is shown schematically in Fig.5;
and operates as discussed below.
The ller tank provides a supply or R-12 / R-134a liquid under its
own partial pressure.
The INCREASE valve controls the amount of refrigerant gas fed
from the ller tank to the ballast tank, the leak-rate gage, and the
leak capillary. The pressure in the system is maintained by the bal-
last tank. With the INCREASE and DECREASE valves closed, the
system is practically in a static state, except for the minute amount of
refrigerant gas that escapes through the leak capillary.
The DECREASE valve provides a means of decreasing the pressure
built up in the system. With the DECREASE valve opened, refriger-
ant gas is allowed to escape through the VENT opening on the front
of the Leak Standard.
The rate of refrigerant gas escaping through the leak capillary is a
function of the pressure in the system and is indicated on the LEAK
RATE gage in ounces per year.
Operation
Fig. 5. Type LS-20B Schematic Diagram

Type LS-20B Leak Standard
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MAINTENANCE
REFILLING LEAK STANDARD
When the supply of liquid refrigerant in the TANK is exhausted,
the Leak Standard will no longer respond to the opening of the
INCREASE valve, which indicates relling is needed. Please read
through all the steps before proceeding.
A 15-ounce can of R-12 / R-134a refrigerant in a “Can-O-Gas” or
“Charg-A-Can” container needs to be procured through your local
refrigeration supply house.
1. Remove screw from center of back cover of Leak Standard, and
then remove and set aside back cover.
2. Remove center section of Leak Standard (the center section has
the handle attached to it), and lay the center section on its side.
WARNING!
It is recommended that safety glasses
with non-perforated side shields be worn
during this relling procedure, as liquid
refrigerant can be damaging to the eyes.
In Steps 3, 4, and 5 below, some refriger-
ant gas may leak out while performing
these steps; therefore, avoid coming in
contact with the gas.
CAUTION:
In order to assure that no dirt or other contamination
gets into the LS-20B during relling operations, make
sure that all couplings and valves are clean.
NOTE: Because refrigerant gas will escape during the
relling operation, this procedure should be performed
outside the testing area to avoid contaminating the air
in the area.
3. Connect the can valve (supplied with the Leak Standard) to the
can of refrigerant in the following manner: