Bosch GAC 250 Professional Concrete Saw: Manual, Safety, and Specifications

Safety Instructions

General Safety for Electric Tools

Read all safety warnings, instructions, illustrations, and specifications provided with this power tool. Failure to follow instructions may result in electric shock, fire, and/or serious injury. Keep all warnings and instructions for future reference.

The term "power tool" refers to your mains-operated (corded) power tool or battery-operated (cordless) power tool.

Work Area Safety

• Keep work area clean and well-lit. Cluttered or dark areas can lead to accidents.
• Do not operate in explosive atmospheres (e.g., presence of flammable liquids, gases, or dust). Sparks from the tool can ignite dust or vapors.
• Keep children and bystanders away from the power tool while in use. Distractions can lead to loss of control.

Electrical Safety

• Tool plugs must match the outlets. Never modify the plug. Do not use adapter plugs with earthed tools. Unmodified plugs and compatible outlets reduce the risk of electric shock.
• Avoid body contact with earthed surfaces (e.g., pipes, heaters, stoves, refrigerators). There is an increased risk of electric shock if your body is earthed.
• Keep power tools away from rain or moisture. Water entering a power tool increases the risk of electric shock.
• Do not misuse the cord. Never use the cord for carrying, pulling, or unplugging the power tool. Keep the cord away from heat, oil, sharp edges, and moving parts. Damaged or tangled cords increase the risk of electric shock.
• When operating outdoors, use an extension cord suitable for outdoor use. This reduces the risk of electric shock.
• If operating in damp locations is unavoidable, use a power supply protected by a residual current device (RCD). Using an RCD reduces the risk of electric shock.

Personal Safety

• Stay alert, pay attention to what you are doing, and use common sense when operating a power tool. Do not use if tired, or under the influence of drugs, alcohol, or medication. A moment of inattention can result in serious personal injury.
• Use personal protective equipment (PPE). Always wear eye protection. PPE such as a dust mask, non-slip safety shoes, safety helmet, or hearing protection, used under appropriate conditions, will reduce the risk of personal injury.
• Avoid unintentional starting. Ensure the switch is in the OFF position before plugging into the power source and/or battery pack, picking up, or carrying the tool. Carrying power tools with your finger on the switch or energizing power tools that have the switch on invites accidents.
• Remove any adjusting key or wrench before turning the power tool on. A wrench or key left attached to a rotating part of the power tool may result in personal injury.
• Avoid abnormal body position. Maintain a firm footing and balance at all times. This enables better control of the power tool in unexpected situations.
• Wear appropriate clothing. Do not wear loose clothing or jewelry. Keep your hair and clothing away from moving parts. Loose clothing, jewelry, or long hair can be caught by moving parts.
• If devices for the connection of dust extraction and collection facilities are provided, ensure these are connected and properly used. Use of dust collection can reduce dust-related hazards.
• Do not let familiarity gained from frequent use of tools make you complacent and ignore tool safety principles. A careless action can cause serious injury in a fraction of a second.

General Handling and Use

• Do not overload the power tool. Use the correct power tool for your application. It is better and safer to work with the power tool appropriately in the power range for which it was designed.
• Do not use the power tool if the switch does not turn it on or off. Any power tool that cannot be controlled with the switch is dangerous and must be repaired.
• Disconnect the plug from the power source and/or remove the battery pack, if it is removable, from the power tool before making any adjustments, changing accessories, or storing the power tool. These preventive safety measures reduce the risk of accidentally starting the power tool.
• Store idle power tools out of reach of children and do not allow persons unfamiliar with the power tool or these instructions to operate the power tool. Power tools are dangerous in the hands of untrained users.
• Handle power tools and accessories with care. Check for misalignment or binding of moving parts, breakage of parts, and any other condition that may affect the operation of the power tool. If damaged, have the power tool repaired before use. Many accidents are caused by improperly maintained power tools.
• Keep cutting tools sharp and clean. Carefully maintained cutting tools with sharp cutting edges are easier to control and less likely to bind.
• Use the power tool, accessories, bits, etc., in accordance with these instructions, taking into account the working conditions and the work to be performed. Use of the power tool for operations different from those intended may result in a hazardous situation.
• Keep handles and gripping surfaces dry, clean, and free from oil and grease. Slippery handles and gripping surfaces do not allow for safe handling and control of the power tool in unexpected situations.

Service

• Have your power tool repaired only by qualified personnel using original spare parts. This ensures that the safety of the power tool is maintained.

Special Safety Instructions for AAC Block Cutter

• With the saw running, keep all body parts away from the saw chain. Before starting the saw, ensure the saw chain does not touch anything. When working with a power tool, a moment of inattention can cause clothing or body parts to become caught in the saw chain.
• Always hold the power tool firmly with both hands, the right hand on the rear handle and the left hand on the front handle. Holding the power tool in an inverted working position increases the risk of injury and should not be used.
• Hold the power tool only by the insulated gripping surfaces, as the saw chain may contact hidden electrical wires or its own power cord. Contact between the saw chain and an energized wire can make exposed metal parts of the tool "live" and cause an electric shock.
• Use eye protection and a dust mask. Additional protective equipment for hearing, head, hands, legs, and feet is recommended. Appropriate protective clothing reduces the risk of injury from flying chips and accidental contact with the saw chain.
• Do not operate the power tool from a ladder, roof, or unstable support. Operating the power tool in this manner can cause serious injury.
• Always ensure a firm footing and use the power tool only when on solid, secure, and level ground. Slippery surfaces or unstable bases can lead to loss of balance or loss of control of the power tool.
• Transport the power tool by the front handle when switched off, with the saw chain pointing forward. Always place the protective cover on the bar when transporting or storing the power tool. Careful handling of the power tool reduces the probability of accidental contact with the moving saw chain.
• Follow the instructions for chain tensioning and for replacing the bar and chain. An incorrectly tensioned chain can break or increase the risk of kickback.
• Saw only porous concrete. Do not use the power tool for tasks for which it is not intended. Example: Do not use the power tool to saw metal, plastic, masonry, soil, ice, or wood. Using the power tool for unintended tasks can lead to hazardous situations.
• Follow all instructions for removing accumulated material, storage, or maintenance of the power tool. Ensure the on/off switch is off and the plug is removed from the power outlet. Accidental activation of the power tool when removing accumulated material or during maintenance can cause serious injury.

Causes and Prevention of Kickback:

Kickback can occur if the tip of the guide bar touches an object. Contact with the bar tip can, in some cases, cause an unexpected reaction backward, where the guide bar is thrown upward and toward the operator. The saw chain jamming on the upper edge of the guide bar can suddenly push the guide bar back toward the operator. Any of these reactions can cause you to lose control of the power tool and possibly suffer serious injury. Do not rely solely on the safety devices integrated into the power tool. As a power tool user, you must take various measures to work without risk of accidents and injuries.

Kickback is the result of incorrect or improper use of the power tool. It can be avoided through appropriate precautionary measures, as described below:

• Always hold the power tool firmly with both hands, gripping the handles with thumbs and fingers. Position your body and arms so you can support kickback forces. With adequate measures, the operator can control kickback forces. Never let go of the power tool.
• Avoid abnormal body posture and never saw above shoulder height. This prevents accidental contact with the bar tip and allows for better control of the power tool in unexpected situations.
• Always use replacement bars, saw chains, and sprockets recommended by the manufacturer. Incorrect replacement bars, saw chains, and sprockets can cause chain breakage or kickback.
• Follow the manufacturer's instructions for saw chain maintenance. Depth limiters that are too low increase the tendency for kickback.

Product Overview and Specifications

Read all safety indications and instructions thoroughly. Failure to observe the safety indications and instructions may cause electric shock, fire, and/or serious injuries. Please observe the illustrations at the beginning of the instruction manual.

Intended Use

The power tool is intended exclusively for cutting porous concrete.

Main Components

The numbering of the illustrated components refers to the representation of the power tool on the diagram page.

• (1) Rear handle
• (2) On/Off switch
• (3) Front handle
• (4) Hand guard/lever for front brake activation
• (5) Serial number
• (6) Bar with sprocket nose
• (7) Chain guard
• (8) TCT saw chain
• (9) Bar
• (10) Depth gauge
• (11) Rotary knob for cover
• (12) Cover
• (13) Tensioning roller
• (14) Lock-off button
• (15) Suction nozzle
• (16) Symbol for direction of movement and cutting direction
• (17) Sprocket
• (18) Fixing pin
• (19) Guide for the blade
• (20) Suction hose
• (21) Pin

a) Not all accessories listed are included with the power tool. Please note the scope of delivery in the product packaging.

Technical Data

Connection processes cause brief voltage drops. If mains conditions are unfavorable, this may affect other appliances. With mains impedances below 0.25 Ohm, disturbances are unlikely.

The specifications are valid for the nominal voltages indicated. These may vary for different voltages and country-specific versions.

Values may vary depending on the product and are subject to application and environmental conditions. More information at www.bosch-professional.com/wac.

Noise/Vibration Information

Noise emission values determined according to EN 62841-1.

A-weighted sound pressure level: typically 95 dB(A); sound power level: 103 dB(A). Uncertainty K = 3 dB.

Wear hearing protection!

Total vibration values ah (vector sum of three directions) and uncertainty K determined according to EN 62841-1:

ah = 3.9 m/s², K = 1.5 m/s².

The vibration levels and noise emission values indicated in these instructions have been determined according to a standardized measurement method and can be used for comparison with other power tools. They are also suitable for a preliminary assessment of vibration and noise emissions.

The indicated vibration levels and noise emission values represent the main applications of the power tool. However, if the power tool is used for other applications, with different attachments, or with insufficient maintenance, vibration and noise emission levels may differ. This can significantly increase vibration and noise emissions during the entire working period.

For an accurate estimate of vibration and noise emissions, periods when the tool is switched off or running but not actually in use should also be considered. This can significantly reduce vibration and noise emissions during the entire working period.

Additional safety measures should be implemented to protect the operator from the effects of vibration, such as: maintenance of the power tool and accessories, wearing gloves, and organizing work processes.

Assembly

For Your Safety

• ⚠️ ATTENTION! Disconnect the power tool before any maintenance or repair work and pull the mains plug. This also applies if the power cord is damaged, cut, or tangled.
• CAUTION! Do not touch the running saw chain.
• Never operate the power tool near people, children, or animals, or after consuming alcohol, drugs, or narcotic medications.

Mounting and Tensioning the Saw Chain

• Connect the power tool to the mains only after complete assembly.
• Always wear protective gloves when handling the saw chain.

Mounting the Bar and Saw Chain (See Figures A-C)

1. Carefully unpack all parts.
2. Place the power tool on a flat surface.
3. Insert the saw chain (8) into the peripheral groove of the bar (9). Pay attention to the correct direction of movement; compare the saw chain with the direction of movement symbol (16).
4. Ensure the tensioning roller (13) is in the ⊝ position.
5. Place the chain links around the sprocket (17) and place the bar (9) onto the fixing pin (18).
6. Note: For initial assembly, the pin (21) must engage in the mounting hole on the bar (9) furthest from the sprocket (17) (see Figure A).
7. Check that all parts are correctly positioned and hold the bar with the chain in this position.
8. Turn the tensioning roller (13) in the ➕ direction until the saw chain is partially tensioned and remains mounted on the bar.
9. Replace the cover (12).
10. Slightly tighten the cover (12) with the rotary knob (11).
11. The saw chain is not yet fully tensioned. Chain tensioning is described in the section "Tensioning the Saw Chain".

Tensioning the Saw Chain (See Figure D)

Check chain tension at regular intervals of 10 minutes before starting work, after the first cuts, and while sawing. New chains may require more frequent adjustment initially. Proper chain tension significantly affects chain life. Incorrect tension can lead to premature wear or kickback.

Do not tension the chain when it is very hot, as it will contract when cooling and become too tight on the bar.

1. Place the power tool on a flat surface.
2. Turn the rotary knob (11) in the ⊝ direction to release the bar lock.
3. Check that the chain links are correctly seated in the guide groove of the bar (9) and on the sprocket (17).
4. Turn the tensioning roller (13) in the ➕ direction until the correct chain tension is achieved. The locking mechanism prevents the chain tension from loosening. If the tensioning roller (13) is difficult to turn, loosen the rotary knob (11) further in the ⊝ direction. The rotary knob (11) may turn along when adjusting the tensioning roller (13). Two hands may be needed to hold the rotary knob (11) in position while adjusting the tensioning roller (13).
5. The saw chain (8) is correctly tensioned if it can be lifted about 3-4 mm in the center. This should be done with one hand, pulling the saw chain upwards against the tool's own weight.
6. If the saw chain (8) is tensioned too tightly, turn the tensioning roller (13) in the ➖ direction.
7. With the saw chain (8) tensioned, secure the bar (9) by turning the rotary knob (11) in the ⊝ direction. Do not use any tools for this.

Operation

Starting Up

Observe the supply voltage! The voltage of the power source must match the specifications on the tool's rating plate. Tools marked 230 V can also be operated at 220 V.

Connecting and Disconnecting

1. Pull the hand guard/lever for front brake activation (4) from the ⊝ position to the ⊞ position towards the front handle (3) (see Figure E). If the hand guard/lever (4) is not activated, the front brake has not been disengaged, and the tool will not start.
2. Remove the chain guard (7).
3. Hold the power tool as described in the "Working with the Power Tool" section.
4. To start the power tool, first push the lock-off button (14) and then press and hold the on/off switch (2).
5. Once the power tool is running, you can release the lock-off button.
6. To switch off the power tool, release the on/off switch (2).

Note: For safety reasons, the on/off switch (2) cannot be locked; it must be continuously pressed during operation.

Note: Do not brake the power tool by activating the front brake (4).

Inertia Brake/Front Brake (See Figure E)

The power tool is equipped with two protective devices:

• The inertia brake stops the saw chain after the on/off switch (2) is released.
• The front brake is a protective mechanism that is activated by the front brake activation lever (4) in case of kickback or switch failure. The saw chain stops immediately.

Perform a function test periodically. Push the front brake activation lever (4) forward (⊞ position) and briefly switch on the power tool. The saw chain must not start. To release the front brake again, pull the front brake activation lever (4) back (⊝ position).

Do not carry the power tool by the front brake activation lever.

Working with the Power Tool

Before Sawing

Before commissioning and regularly during sawing, the following checks must be performed:

• Is the power tool in a safe condition?
• Is the saw chain correctly tensioned and sharp? Check chain tension regularly every 10 minutes of use. New chains may require more frequent adjustment initially. Chain condition significantly affects saw performance. Only sharp chains protect against overload.
• Is the front brake released and functioning correctly?
• Are you using the necessary protective equipment? Use safety glasses, dust mask, and hearing protection. Additional protection for head, hands, legs, and feet is recommended. Appropriate protective clothing reduces the risk of injury from flying chips and accidental contact with the saw chain.

Saw Kickback (See Figure E)

Saw kickback is the sudden upward and backward movement of the running power tool, which can occur if the guide bar tip contacts the material being cut or if the chain jams. When kickback occurs, the power tool reacts unpredictably and can cause serious injury to the operator or bystanders. Side, oblique, or longitudinal cuts must be initiated carefully, as the depth gauge (10) cannot be applied. To avoid saw kickback:

• Support the power tool as flatly as possible.
• Never work with a loose, stretched, or excessively worn saw chain.
• Never saw above shoulder height.
• Never saw with the guide bar tip.
• Always hold the power tool firmly with both hands.
• Always use a Bosch saw chain for porous concrete (accessory).
• Use the depth gauge (10) as a lever.
• Pay attention to correct chain tension.

General Handling (See Figures E-H)

Always hold the power tool firmly with both hands, left hand on the front handle and right hand on the rear handle. Always grip the handles with your thumbs and fingers. Always guide the power cord backwards and keep it away from the saw chain and the material being cut.

Operate the power tool only with secure footing. Hold the power tool slightly to the right of your body.

The saw chain must be running at full speed before contacting the porous concrete. Use the depth gauge (10) to support the power tool on the porous concrete. Use the depth gauge as a lever when sawing.

When sawing thicker porous concrete blocks, reposition the depth gauge lower. To do this, pull the power tool backward to release the depth gauge and reposition it lower. Do not remove the power tool from the cut while doing this.

When sawing, do not apply excessive force to the saw chain; let it work by applying light leverage pressure via the depth gauge (10).

Never operate the power tool with outstretched arms. Do not attempt to saw in hard-to-reach areas or while standing on a ladder. Never saw above shoulder height.

The best sawing results are achieved when the chain speed does not decrease due to overload.

Be careful at the end of the cut. As soon as the power tool is released, the weight force changes unexpectedly. There is a risk of injury to legs and feet.

Remove the power tool from the cut only with the saw chain running.

Sawing Porous Concrete (See Figures G-H)

Observe the following safety rules when sawing porous concrete:

• Position the porous concrete as shown in the figure and support it so that the cut does not close and jam the saw chain.
• Align and secure shorter pieces of porous concrete before sawing.
• Only saw porous concrete objects. Avoid hitting stones and nails, as these can be ejected, damage the saw chain, or cause serious injury to the user or bystanders.
• Do not touch wire fences or the ground with the power tool running.
• Perform longitudinal cuts with particular care, as the depth gauge (10) cannot be used. Guide the power tool at a shallow angle to prevent saw kickback.

Maintenance and Service

Maintenance and Cleaning

• Before any work on the power tool, disconnect the mains plug.
• Keep the power tool and ventilation slots clean for efficient and safe operation.
• For extreme use conditions, always use a dust extraction system if possible. Frequently clear ventilation slots by blowing air into them and connect the appliance via a residual current device (RCD).
• If the power cord needs replacement, it must be done by Bosch or an authorized Bosch service center to avoid safety risks.

Note: Perform the following maintenance tasks regularly to ensure long-lasting and reliable use.

• Check that covers and protective devices are undamaged and correctly fitted. Perform any necessary maintenance or repair work before use.
• Periodically inspect the power tool for obvious defects, such as a loose, slack, or damaged saw chain, loose fastenings, and worn or damaged components.

Saw Chain and Sprocket Replacement

Replace the saw chain and sprocket with original Bosch spare parts or have them replaced by an authorized Bosch power tool service center.

After Work/Storage

• Place the chain guard (7) over the bar (9) to prevent injuries.
• The saw chain (8) can become dull due to impacts or unwanted scratches.
• Clean the molded plastic housing of the power tool with a soft brush and a clean cloth. Do not use water, solvents, or polishing agents. Remove all dirt, especially from the motor ventilation slots.
• After 1-3 hours of use, remove the cover (12), bar (9), and saw chain (8) and clean them with a brush.
• If the power tool is to be stored for a longer period, clean the saw chain (8) and bar (9).
• Store the power tool in a safe, dry place out of reach of children.
• Do not place other objects on the power tool.
• Do not make any modifications to the power tool. Unauthorized modifications can compromise its safety and increase noise and vibration.

Troubleshooting

The following table shows error symptoms and how to resolve them if your power tool stops working. If you cannot locate and eliminate the problem this way, contact your service workshop.

⚠️ Attention: Before troubleshooting, disconnect the power tool and unplug it from the mains.

Service and Support

Service and Cleaning

• Before any work on the power tool, disconnect the mains plug.
• Keep the power tool and ventilation slots clean for efficient and safe operation.
• For extreme use conditions, always use a dust extraction system if possible. Frequently clear ventilation slots by blowing air into them and connect the appliance via a residual current device (RCD).
• If the power cord needs replacement, it must be done by Bosch or an authorized Bosch service center to avoid safety risks.

Note: Perform the following maintenance tasks regularly to ensure long-lasting and reliable use.

• Check that covers and protective devices are undamaged and correctly fitted. Perform any necessary maintenance or repair work before use.
• Periodically inspect the power tool for obvious defects, such as a loose, slack, or damaged saw chain, loose fastenings, and worn or damaged components.

Saw Chain and Sprocket Replacement

Replace the saw chain and sprocket with original Bosch spare parts or have them replaced by an authorized Bosch power tool service center.

After Work/Storage

• Place the chain guard (7) over the bar (9) to prevent injuries.
• The saw chain (8) can become dull due to impacts or unwanted scratches.
• Clean the molded plastic housing of the power tool with a soft brush and a clean cloth. Do not use water, solvents, or polishing agents. Remove all dirt, especially from the motor ventilation slots.
• After 1-3 hours of use, remove the cover (12), bar (9), and saw chain (8) and clean them with a brush.
• If the power tool is to be stored for a longer period, clean the saw chain (8) and bar (9).
• Store the power tool in a safe, dry place out of reach of children.
• Do not place other objects on the power tool.
• Do not make any modifications to the power tool. Unauthorized modifications can compromise its safety and increase noise and vibration.

Service and Contact

The technical service will advise you on queries concerning repair and maintenance of your product, as well as on spare parts. Three-dimensional graphic representations and spare part information can also be found at: www.bosch-pt.com

The Bosch application advisory team will gladly assist you with questions about our products and accessories.

For any query or spare part order, it is essential to state the 10-digit article number found on the product's rating plate.

Mexico

Robert Bosch S. de R.L. de C.V.
Calle Robert Bosch No. 405
C.P. 50071 Zona Industrial, Toluca - Estado de México
Tel.: (52) 55 528430-62
Tel.: 800 6271286
www.boschherramientas.com.mx

Additional service addresses can be found at:

www.bosch-pt.com/serviceaddresses

Disposal

We recommend that power tools, accessories, and packaging be subjected to an environmentally compatible recycling process.

Do not throw power tools into household waste!

The NOM symbol is only valid if it is also found on the product/manufacturer's rating plate.

Spare Parts

The following are common spare parts for the GAC 250 Professional:

• Saw Chain TCT (2 604 730 027)
• Sprocket (2 604 730 028)
• Bar (2 602 317 081)
• Suction Hose Adapter (2 608 000 808)

Related Accessories (Vacuum Cleaners)

The GAC 250 Professional can be connected to the following Bosch vacuum cleaners for dust extraction:

• GAS 35 M AFC
• GAS 55 M AFC

Hoses available:

• Ø 22 mm: 2 608 000 572 (3 m), 2 608 000 568 (5 m)
• Ø 35 mm: 2 608 000 570 (3 m), 2 608 000 566 (5 m)

Antistatic hoses also available:

• Ø 22 mm: 2 608 000 571 (3 m), 2 608 000 567 (5 m)
• Ø 35 mm: 2 608 000 569 (3 m), 2 608 000 565 (5 m)