Bosch Professional GAC 250 Original Instructions Manual page 22

22 | English
Working with the Power Tool
Before Cutting
The following checks must be performed before starting op-
eration and regularly during sawing:
– Is the power tool in a safe state?
– Is the saw chain tensioned and sharpened correctly? Dur-
ing sawing, check the chain tension regularly every ten
minutes. Particularly when using new saw chains, in-
creased extension should be expected initially. The state
of the saw chain greatly influences the sawing perform-
ance. Only sharp saw chains protect against overload.
– Is the front brake released and its function ensured?
– Are you wearing the required protective equipment? Use
safety goggles, a dust mask and hearing protection. It is
recommended that you wear additional protective equip-
ment for your head, hands, legs and feet. Wearing suit-
able protective clothing reduces the risk of injury from fly-
ing cut material and the saw chain accidentally coming
into contact with an object.
Saw Kickback (see figure E)
A saw kickback is the sudden uncontrolled movement and
kickback of the running power tool, which can occur if the tip
of the chain bar comes into contact with the material to be
sawn or if the chain jams.
If a kickback occurs, the power tool may respond unpredict-
ably and cause severe injuries to the operator or bystanders
in the cutting area.
Particular care must be taken for lateral, bevel and rip cuts
because the stop (10) cannot be applied.
To prevent saw kickbacks:
– Position the power tool so that it is as flat as possible.
– Never work with a loose, extended or heavily worn saw
chain.
– Never saw above shoulder height.
– Never saw using the tip of the chain bar.
– Always hold the power tool firmly with both hands.
– Always use a Bosch saw chain for autoclaved aerated con-
crete (accessory).
– Use the stop (10) as a lever.
– Make sure that the chain tension is correct.
General Behaviour (see figures E–H)
Always hold the power tool firmly with both hands, with your
left hand on the front handle and your right hand on the rear
Troubleshooting
The following table shows fault symptoms and how you can remedy the problem if your power tool does not work properly. If
this does not enable you to locate and rectify the problem, contact your service workshop.
Important: Before troubleshooting, switch off the
u
power tool and pull out the mains plug.
1 609 92A 6BF | (25.10.2022)
handle. Always grasp the handles with your thumb and fin-
ger. Always guide the mains cable to the rear and keep it out-
side the area of the saw chain and material to be sawn.
Ensure you always have a secure footing when operating the
power tool.Hold the power tool slightly to the right of your
body.
The saw chain must be running at full speed before coming
into contact with the autoclaved aerated concrete. To do
this, use the stop (10) to support the power tool on the auto-
claved aerated concrete. During sawing, use the stop as a
lever.
When sawing heavier autoclaved aerated concrete blocks,
reposition the stop at a lower point. To do this, pull the
power tool back to release the stop and reposition it at a
lower point. Do not remove the power tool from the cut.
Do not press on the saw chain with force, let it run by using
the stop (10) to create a slight leverage pressure.
Never operate the power tool with extended arms. Do not at-
tempt to operate the saw in hard-to-reach places or when
standing on a ladder. Never saw above shoulder height.
The best sawing results are achieved when the chain speed
is not reduced due to overload.
Be careful at the end of the saw cut. As soon as the power
tool has cut through, the weight force will change unexpec-
tedly. There is a risk of injury to legs and feet.
Only remove the power tool from the cut with the saw chain
running.
Sawing Autoclaved Aerated Concrete (see
figures G–H)
When sawing autoclaved aerated concrete, refer to the fol-
lowing safety regulations:
Set down the autoclaved aerated concrete as shown in the
figure and support it such that the cut does not close and the
saw chain jams.
Before sawing, set up shorter autoclaved aerated concrete
structures and secure them in place.
Only saw objects made of autoclaved aerated concrete.
Avoid coming into contact with stones and nails because
they may be hurled upwards and damage the saw chain or
cause serious injuries to the user or bystanders.
Do not bring the running power tool into contact with wire
fencing or the ground.
Exercise particular caution when making rip cuts because
the stop (10) cannot be used. Guide the power tool at a shal-
low angle in order to avoid saw kickbacks.
Bosch Power Tools