BOSCH GMS 120 Professional Detector Instructions

: June 3, 2024
: Bosch

BOSCH GMS 120 Professional Detector

Safety Notes

Read and observe all instructions. SAVE THESE INSTRUCTIONS FOR FUTURE REFERENCE.

Have the measuring tool repaired only through qualified specialists using original spare parts. This ensures that the safety of the measuring tool is maintained.
Do not operate the measuring tool in explosive environments, such as in the presence of flammable liquids, gases or dusts. Sparks can be created in the measuring tool which may ignite the dust or fumes.

Functional Description

Please unfold the fold-out page with the representation of the measuring tool and leave it unfolded while reading the operating instructions.

Intended Use

The measuring tool is intended for the detection of metals (ferrous and non- ferrous metals, e.g., rebar), joists and “live” wires/conductors in walls, ceilings and floors.

Product Features

The numbering of the product features shown refers to the illustration of the measuring tool on the graphic page.

Illuminated ring
Marking hole
Display
Operating-mode indication
On/Off button
Display-illumination button
Audio signal button
Button for detecting “live” conductors/ Operating mode “Power cable”
Button for metal detection/ Operating mode “Metal”
Button for detecting wood and metal beams/Operating mode “Drywall”
Contact pads
Sensor area
Type plate
Battery lid
Latch of battery lid
Fixture for carrying strap
Protective pouch
Carrying strap

Accessories shown or described are not part of the standard delivery scope of the product. A complete overview of accessories can be found in our accessories program.

Display Elements (see figure A)

a Switched-off audio signal indicator
b Warning-function indicator
c Indication of the object type “Non-metal object”
d Indication of the object type “Non-magnetic metal”
e Indication of the object type “Magnetic metal”
f Indication of the object type “Live conductor”
g Temperature control indicator
h Battery indicator
i Measuring indicator
j Fine scale
k Indication “CENTER”

Technical Data

Digital Detector

|

GMS 120 Professional

---|---
Article number| 3 601 K81 000
Maximum scanning depth*|
– Ferrous metals| 120 mm
– Non-ferrous metals (copper)| 80 mm
– Live conductors 110 V/230 V (voltage applied)**| 50 mm
– Wood| 38 mm
Automatic switch-off after approx.| 5 min
Operating temperature| –10 °C … +50 °C
Storage temperature| –20 °C … +70 °C
Battery| 1 x 9 V 6LR61
Operating life time, approx.| 5 h
Weight according to EPTA-Procedure 01/2003| 270 g

Assembly

Inserting/Replacing the Battery

Alkali-manganese batteries are recommended for the measuring tool.
To open the battery lid 14, press the latch 15 in the direction of the arrow and fold up the battery lid. Insert the supplied battery. Pay attention that the polarity is correct, according to the representation on the inside of the battery lid.
The battery indicator h always indicates the current battery status:

Battery fully charged
Battery has 2/3 of its capacity or less
Battery has 1/3 of its capacity or less
Please change battery

If the measuring tool is not used for a long period of time, the battery must be removed. The battery can corrode or discharge itself over long periods.

Operation

Protect the measuring tool against moisture and direct sun light.
Do not subject the measuring tool to extreme temperatures or variations in temperature. In case of large variations in temperature, allow the measuring tool to adjust to the ambient temperature before switching it on. In case of extreme temperatures or variations in temperature, the accuracy of the measuring tool and the display indication can be impaired.
Use or operation of transmitting systems, such as WLAN, UMTS, radar, transmitter masts or microwaves, in the close proximity can influence the measuring function.

Initial Operation

Switching On and Off

Before switching the measuring tool on, make sure that the sensor area 12 is not moist. If required, dry the measuring tool using a soft cloth.
If the measuring tool was subject to an extreme temperature change, allow it to adjust to the ambient temperature before switching on.

To switch on the measuring tool, press the On/Off button 5.
To switch off the measuring tool, press the On/Off button 5 again.
When no button on the measuring tool is pressed for approx. 5 minutes and when no objects are detected, the measuring tool automatically switches off to save the battery.

Switching the Display Illumination On/Off

The display illumination can be switched on/off with display-illumination button 6.

Switching the Audio Signal On/Off

The audio signal can be switched on/off with the audio signal button 7. When the audio signal is switched off, indication a appears on the display.

Method of Operation (see figures A–B)

The measuring tool checks the base material of sensor area 12 in measurement direction A to the max. detection depth (see “Technical Data”). Objects are detected that differ from the material of the wall.
Always move the measuring tool in a straight line over the surface applying slight pressure, without lifting it off or changing the pressure. During measurement, the contact pads 11 must always have contact to the surface.

Measuring Procedure

Position the measuring tool on/against the surface being detected, and move it in direction B. When the measuring tool comes closer to an object, the amplitude in measuring indicator increases and ring 1 lights up yellow; when it is moved away from the object, the amplitude decreases. Measuring indicator i indicates the maximal amplitude above the center of the object; ring 1 lights up red and an audio signal sounds. For small or deeply embedded objects, ring 1 can continue to light up yellow, while there is no audio signal.

Wide objects are not indicated by the illuminated ring or the audio signal throughout their complete width.

To localize the object more precisely, move the measuring tool repeatedly (3x) back and forth over the object. The fine scale j is automatically activated in all operating modes. Fine scale j indicates a full amplitude when the object is below the centre of the sensor or when the maximum amplitude of measuring indicator is reached. In the operating modes “Drywall” and “Metal”, the indication “CENTER” k lights up additionally.

Wider objects in the base material are detected through a continuous, high amplitude of measuring indicators i and j. Ring 1 lights up yellow. The duration of the high amplitude corresponds approximately with the object width. When very small or deeply embedded objects are being sought and measuring indicator i reacts only slightly, move the measuring tool repeatedly over the object in horizontal and vertical direction. Pay attention to the amplitude of fine scale j, and when in operating mode “Drywall” and “Metal”, additionally to the “CENTER ” k indication, which will then allow for precise detection.

Operating Modes

The best measuring results are achieved through selection of the operating modes. The maximal detection depth for metal objects is achieved in the operating mode “Metal”. The maximal detection depth for “live” conductors is achieved in the operating mode “Power cable”. The selected operating mode can be recognized at any time via the green illuminated operating mode indication 4.

Drywall

The operating mode “Drywall” is suitable for detecting wood or metal objects in drywalls. Press button 10 to activate the operating mode “Drywall”. The operating-mode indication 4 above button 10 lights up green. As soon as the measuring tool is positioned against the base material to be detected, ring 1 lights up greensand signals operational readiness

In the operating mode “Drywall” all object types are detected and indicated

Non-metal, e.g. a wood beam
Magnetic, e.g. reinforcing steel
Non-magnetic, but metal, e.g. copper pipe
“Live”, e.g. a “live” conductor

Notes: In the operating mode “Drywall”, other objects, apart from wood and metal objects and “live” conductors are also detected, such as plastic tubing filled with water. For such objects, the indication c for non-metal objects is indicated in display 3.
Nails and screws in the base material may cause a wooden beam to be indicated as a metal object on the display.
When display 3 indicates a continuously high amplitude of measuring indicator i and fine scale j, restart the measuring procedure again by positioning the measuring tool at a different location on the base material.

When the illuminated ring 1 does not signal operational readiness when positioning the measuring tool on the base material being detected, the measuring tool cannot properly detect the base material.

Press and hold button 10 until the illuminated ring lights up green.
When starting a new measuring procedure afterwards and positioning the measuring tool onto a different wall or surface, you must briefly press button 10.
In rare cases, the measuring tool may not be able to detect the base material because the side with the sensor area 12 and the type plate 13 is soiled or dirty. Clean the measuring tool with a dry, soft cloth and restart the measuring procedure.

Metal

The operating mode “Metal” is suitable for detecting magnetic and non-magnetic objects independent of the wall material. Press button 9 to activate the operating mode “Metal”. The illuminated ring 1 and indication 4 above button 9 light up green. When the detected metal object is of magnetic metal (e.g. iron), the symbol e is indicated on display 3. For non-magnetic metals, the symbol is indicated. In order to differentiate between metal types, the measuring tool must be positioned above the detected metal object (ring 1 is lit red).

Note: For reinforcement steel mesh and steel in the examined base material, an amplitude is indicated over the complete surface of measuring indicator i. For reinforcement steel mesh, it is typical that the symbol e for magnetic metal is indicated on the display directly above the iron rods, whereas between the iron rods, the symbol d for non-magnetic metal will appear.

Power Cable

The operating mode “Power cable” is suitable only for detecting “live” conductors (110–230 V).
Press button 8 to activate the operating mode “Power cable”. The illuminated ring 1 and indication 4 above button 8 light up green.
When a “live” conductor is detected, indication f appears on the display 3. Move the measuring tool repeatedly over the area to localize the “live” conductor more precisely. After moving over the “live” conductor several times, it can be indicated very accurately. When the measuring tool is very close to the conductor, the illuminated ring 1 flashes red and the audio signal beeps swiftly.

Notes

“Live” conductors are indicated in any operating mode.
“Live” conductors can be detected easier when power consumers (e.g. lamps, machines) are connected to the sought conductor and switched on.
Under certain conditions (such as below metal surfaces or behind surfaces with high water content), “live” conductors cannot be securely detected. The signal strength of a “live” conductor depends on the position of the cable. Therefore, apply further measurements in close proximity or use other information sources to check if a “live” conductor exists.
Voltage-free conductors can be detected as metal objects in the operation mode “Metal”. This does not apply for stranded conductors (contrary to solid conductors or cable).
Static electricity can lead to inaccurate indication of electric lines, e.g., over a large range. To improve the indication, place your free hand flat on the wall next to the measuring tool, in order to remove the static electricity.

Working Advice

Measuring values can be impaired through certain ambient conditions. These include, e.g., the proximity of other equipment that produce strong magnetic or electromagnetic fields, moisture, metallic building materials, foil-laminated insulation materials or conductive wallpaper or tiles. Therefore, please also observe other information sources (e.g. construction plans) before drilling, sawing or routing into walls, ceilings or floors.

Marking Objects

If required, detected objects can be marked. Perform a measurement as usual. Once you have found the boundaries or the center of an object, mark the sought location through the marking hole 2.

Temperature Control

The measuring tool is equipped with a temperature control indicator, as accurate measurements are only possible as long as the temperature within the measuring tool remains constant.
When the temperature control indicator g lights up, the measuring tool is not within the operating temperature range or was subject to large variations in temperature. Switch the measuring tool off and allow it to adjust to the ambient temperature before switching it on again.

Warning Function

When indicator b lights up on display 3 and indication 4 flashes above button 10, the measurement must be restarted. Remove the measuring tool from the wall and place it on the base material at a different location. When indicator b flashes on display 3, send the measuring tool in the provided protective pouch to an authorized customer services agent.

Recalibration

When measuring indicator i indicates a continuously high amplitude in the operating mode “Metal”, even though there is no metal object near the measuring tool, the measuring tool can be manually recalibrated.

Switch the measuring tool off.
Removal all objects near the measuring tool that could be detected, including your wrist watch or rings made of metal, and hold the measuring tool up. Pay attention that battery indicator h indicates at least 1/3 capacity:
Hold the measuring tool in such a manner that the type plate 13 faces toward the ground. Avoid bright light sources or direct sunlight from shining on the area 12 and 13, without covering off this area.
Press and hold buttons 5 and 7 until the illuminated ring 1 lights up red. Then release both buttons.
When the calibration was successful, the measuring tool will automatically start after a few seconds, and will be ready for operation again.

Note: If the measuring tool does not automatically start, repeat the recalibration. If the measuring tool still does not start, send it in the provided protective pouch to an authorized customer services agent.

Maintenance and Service

Maintenance and Cleaning

Check the measuring tool each time before use. In case of visible damage or loose components inside the measuring tool, safe function can no longer be ensured.

Keep the measuring tool clean and dry at all times to ensure proper and safe working. Do not immerse the measuring tool in water or other fluids.
Wipe away debris or contamination with a dry, soft cloth. Do not use cleaning agents or solvents. In order not to affect the measuring function, decals/stickers or name plates, especially metal ones, may not be attached in the sensor area 12 on the front or back side of the measuring tool.
Do not remove the contact pads 11 on the backside of the measuring tool.
If the measuring tool should fail despite the care taken in manufacturing and testing procedures, repair should be carried out by an authorized after-sales service center for Bosch power tools.
Do not open the measuring tool yourself. In all correspondence and spare parts orders, please always include the 10-digit article number given on the type plate of the measuring tool. Store and transport the measuring tool only in the supplied protective pouch.
In case of repairs, send in the measuring tool packed in its protective pouch 17.

After-sales Service and Customer Assistance

Our after-sales service responds to your questions concerning maintenance and repair of your product as well as spare parts. Exploded views and information on spare parts can also be found under:
www.bosch-pt.com
Our customer service representatives can answer your questions concerning possible applications and adjustment of products and accessories.

Great Britain
Robert Bosch Ltd. (B.S.C.)
P.O. Box 98
Broadwater Park
North Orbital Road
Denham
Uxbridge
UB 9 5HJ
Tel. Service: +44 (0844) 736 0109
Fax: +44 (0844) 736 0146
E-Mail: boschservicecentre@bosch.com

Ireland
Origo Ltd.
Unit 23 Magna Drive
Magna Business Park
City West
Dublin 24
Tel. Service: +353 (01) 4 66 67 00
Fax: +353 (01) 4 66 68 88

Australia, New Zealand and Pacific Islands
Robert Bosch Australia Pty. Ltd.
Power Tools
Locked Bag 66
Clayton South VIC 3169
Customer Contact Center
Inside Australia:
Phone: +61 (01300) 307 044
Fax: +61 (01300) 307 045
Inside New Zealand:
Phone: +64 (0800) 543 353
Fax: +64 (0800) 428 570
Outside AU and NZ:
Phone: +61 (03) 9541 5555
www.bosch.com.au

Republic of South Africa
Customer service
Hotline: +27 (011) 6 51 96 00

Gauteng – BSC Service Centre
35 Roper Street, New Centre
Johannesburg
Tel.: +27 (011) 4 93 93 75
Fax: +27 (011) 4 93 01 26
E-Mail: bsctools@icon.co.za

KZN – BSC Service Centre
Unit E, Almar Centre
143 Crompton Street
Pinetown
Tel.: +27 (031) 7 01 21 20
Fax: +27 (031) 7 01 24 46
E-Mail: bsc.dur@za.bosch.com

Western Cape – BSC Service Centre
Democracy Way, Prosperity Park
Milnerton
Tel.: +27 (021) 5 51 25 77
Fax: +27 (021) 5 51 32 23
E-Mail: bsc@zsd.co.za

Bosch Headquarters
Midrand, Gauteng
Tel.: +27 (011) 6 51 96 00
Fax: +27 (011) 6 51 98 80
E-Mail: rbsa-hq.pts@za.bosch.com

People’s Republic of China
Website: www.bosch-pt.com.cn

China Mainland
Bosch Power Tools (China) Co., Ltd.
567, Bin Kang Road
Bin Jiang District 310052
Hangzhou, P.R.China
Service Hotline: 800 8 20 84 84
Tel.: +86 (571) 87 77 43 38
Fax: +86 (571) 87 77 45 02

HK and Macau Special Administrative Regions
Robert Bosch Hong Kong Co. Ltd.
21st Floor, 625 King’s Road
North Point, Hong Kong
Customer Service Hotline: +852 (21) 02 02 35
Fax: +852 (25) 90 97 62
E-Mail: info@hk.bosch.com
www.bosch-pt.com.cn

Indonesia
PT. Multi Tehaka
Kawasan Industri Pulogadung
Jalan Rawa Gelam III No. 2
Jakarta 13930
Indonesia
Tel.: +62 (21) 46 83 25 22
Fax: +62 (21) 46 82 86 45/68 23
E-Mail: sales@multitehaka.co.id
www.multitehaka.co.id

Philippines
Robert Bosch, Inc.
28th Floor Fort Legend Towers,
3rd Avenue corner 31st Street,
Fort Bonifacio Global City,
1634 Taguig City, Philippines
Tel.: +63 (2) 870 3871
Fax: +63 (2) 870 3870
matheus.contiero@ph.bosch.com
www.bosch-pt.com.ph
Bosch Service Center:
9725-27 Kamagong Street
San Antonio Village
Makati City, Philippines
Tel.: +63 (2) 899 9091
Fax: +63 (2) 897 6432
rosalie.dagdagan@ph.bosch.com

Malaysia
Robert Bosch (S.E.A.) Pte. Ltd.
No. 8A, Jalan 13/6
G.P.O. Box 10818
46200 Petaling Jaya
Selangor, Malaysia
Tel.: +60 (3) 7966 3194
Fax: +60 (3) 7958 3838
cheehoe.on@my.bosch.com
Toll-Free: 1800 880 188
www.bosch-pt.com.my

Thailand
Robert Bosch Ltd.
Liberty Square Building
No. 287, 11 Floor
Silom Road, Bangrak
Bangkok 10500
Tel.: +66 (2) 6 31 18 79 – 18 88 (10 lines)
Fax: +66 (2) 2 38 47 83
Robert Bosch Ltd., P. O. Box 2054
Bangkok 10501, Thailand
Bosch Service – Training Centre
2869-2869/1 Soi Ban Kluay
Rama IV Road (near old Paknam Railway)
Prakanong District
10110 Bangkok
Thailand
Tel.: +66 (2) 6 71 78 00 – 4
Fax: +66 (2) 2 49 42 96
Fax: +66 (2) 2 49 52 99

Singapore
Robert Bosch (SEA) Pte. Ltd.
11 Bishan Street 21
Singapore 573943
Tel.: +65 6571 2772
Fax: +65 6350 5315
leongheng.leow@sg.bosch.com
Toll-Free: 1800 333 8333
www.bosch-pt.com.sg

Vietnam
Robert Bosch Vietnam Co. Ltd
10/F, 194 Golden Building
473 Dien Bien Phu Street
Ward 25, Binh Thanh District
84 Ho Chi Minh City
Vietnam
Tel.: +84 (8) 6258 3690 ext. 413
Fax: +84 (8) 6258 3692
hieu.lagia@vn.bosch.com
www.bosch-pt.com

Disposal

Measuring tools, accessories and packaging should be sorted for environmental- friendly recycling.

Only for EC countries

Do not dispose of measuring tools into household waste! According the European Guideline 2002/96/EC for Waste Electrical and Electronic Equipment and its implementation into national right, measuring tools that are no longer usable must be collected separately and disposed of in an environmentally correct manner.

Battery packs/batteries

Do not dispose of battery packs/batteries into household waste, fire or water. Battery packs/ batteries should, if possible, be discharged, collected, recycled or disposed of in an environmental-friendly manner.

Only for EC countries

Defective or dead out battery packs/batteries must be recycled according the guideline 2006/66/EC.
Batteries no longer suitable for use can be directly returned at:

Great Britain

Robert Bosch Ltd. (B.S.C.)
P.O. Box 98
Broadwater Park
North Orbital Road
Denham
Uxbridge
UB 9 5HJ
Tel. Service: +44 (0844) 736 0109
Fax: +44 (0844) 736 0146
E-Mail: boschservicecentre@bosch.com

Declaration of Conformity

We declare under our sole responsibility that the product described under „Technical Data“ is in conformity with the following standards or standardization documents:

EN 61010-1:2001-03,
EN 61326-1:2006-05,
EN 301489-3:2002-08,
EN 301489-1:2008-04,
EN 300330-1:2010-02,
EN 300330-2:2010-02
according to the provisions of the directives 2004/108/EC, 1999/5/EC.

Dr. Egbert Schneider Senior Vice President Engineering