HTC 420 VS User manual

MANUAL
HTC 420 VS
GB

Contact Information
HTC Sweden AB
Box 69
SE-614 22 Söderköping - Sweden
Tel: [phone]
Fax: [phone]
You can find addresses for our retailers and service partners on our
website:
www.htc-sweden.com
Always specify the model and serial number when asking questions
about your product.
Trademarks
HTC is a trademark owned by HTC Sweden AB. Other names and
products mentioned in this manual may be registered trademarks
owned by the relevant companies.
© 2007 HTC Sweden AB. All rights reserved.

Declaration of conformity
In accordance with EMC 2004/108/EC, LVD 2006/95/EC, MD
2006/42/EC
Type of equipment Grinder
Make HTC
Trademark HTC 420 VS
Manufacturer HTC Sweden AB
Box 69
614 22 Söderköping
The product was CE marked in 2004.
As the manufacturer, we hereby declare under sole responsibility
that the product conforms with the terms of the directives listed
above.
Sten Jeansson, CEO

HTC 420 VS Table of contents
Table of contents
1. Introduction.........................................................1
1.1 General......................................................................... 1
1.2 Liability.......................................................................... 1
1.3 Manual.......................................................................... 1
1.3.1 Safety instructions – explanation of symbols........1
1.4 Transportation............................................................... 2
1.5 On delivery....................................................................2
1.6 Unpacking the machine................................................ 3
1.7 Machine name plate..................................................... 3
1.8 Handling and storage................................................... 3
1.9 Vibrations and noise..................................................... 3
2. Safety...................................................................4
2.1 General......................................................................... 4
2.2 Warnings....................................................................... 4
2.3 Observations.................................................................5
3. Machine description.......................................... 7
3.1 General machine description........................................7
3.2 Description of controls – Control panel........................ 9
4. Operation...........................................................11
4.1 General....................................................................... 11
4.2 Handle settings........................................................... 13
4.3 Access to grinding tools............................................. 13
4.4 Fitting and replacing grinding tools.............................14
4.4.1 Fitting grinding tools........................................... 14
4.4.2 Changing grinding tools......................................15
4.5 Preparations for dry grinding...................................... 16
4.6 Preparations for wet grinding..................................... 17
4.7 Control........................................................................ 18
4.7.1 Standby ............................................................. 18
4.7.2 Emergency stop switch...................................... 18
4.7.3 Starting the machine.......................................... 18
4.7.4 Overload............................................................. 19
4.8 Making operation easier............................................. 20

Table of contents HTC 420 VS
5. Maintenance and repairs.................................21
5.1 General....................................................................... 21
5.2 Cleaning......................................................................21
5.3 Daily............................................................................ 21
5.4 Every week................................................................. 21
5.5 Every month (or 100 hours)....................................... 22
5.6 Repairs........................................................................22
6. Troubleshooting............................................... 23
6.1 General ......................................................................23
6.1.1 The machine will not start.................................. 23
6.1.2 The machine vibrates or wears the tool
unevenly.......................................................................23
6.1.3 The machine is grinding unevenly......................23
6.1.4 The machine stops immediately after
starting......................................................................... 24
6.1.5 The fuses trip frequently.....................................24
6.1.6 The machine cannot cope.................................. 24
7. Electronic error codes.....................................25
7.1 General....................................................................... 25
7.2 Resetting the frequency converter..............................27
7.3 Checking the last error code...................................... 27
8. Spare parts....................................................... 28
8.1 Chassis....................................................................... 28
8.2 Handle.........................................................................30
8.3 Grinding head 1..........................................................32
8.4 Grinding head 2..........................................................34
8.5 Grinding holder........................................................... 36
9. Technical data.................................................. 38
10. Environment................................................... 40
11. Warranty and CE Marking............................. 41
11.1 Warranty ...................................................................41
11.2 CE marking............................................................... 41

HTC 420 VS Introduction
2.0 1
1. Introduction
1.1. General
HTC 420 VS is a grinder that can be used to grind, strip, clean and
polish concrete, unhewn stone and terrazzo floors. The areas of
application for the machine depend on the choice of tool.
Read through this manual carefully so that you know how to use
and maintain the machine before using it. Contact your retailer for
more information. For contact information, see Contact Information
at the start of the manual.
1.2. Liability
Although every effort has been made to ensure that the information
in this manual is correct and complete, we accept no responsibility
for errors or omissions. HTC reserves the right to change the
descriptions contained in this manual without prior notice.
This manual is protected by copyright law and no part of it may be
copied or used in any way without the written approval of HTC.
1.3. Manual
In addition to general functions, this manual deals with areas of
application and maintenance of the grinder.
1.3.1. Safety instructions – explanation of symbols
In order to clearly mark particularly important sections, there are
a number of symbols in the manual – see below. In order to avoid
both personal injury and material damage as much as possible, it is
extremely important to read and understand the text next to these
symbols particularly carefully. Practical tips are also marked with a
symbol. These tips are to make it easier to use the machine and to
get maximum benefit from it.
The following symbols are used in the document to highlight for
the reader when to be observant.
This symbol means Warning! and indicates a risk of personal
injury or material damage in the event of incorrect use of the
machine or associated equipment. If you see this symbol next to

Introduction HTC 420 VS
2 2.0
a section of text, you must pay particular attention when reading
through the text and not carry out any operations of which you are
unsure. This is for your own and other users’ safety and to avoid
damage to machinery or other equipment.
This symbol means Note! and indicates a potential risk of material
damage in the event of incorrect use of the machine or associated
equipment. If you see this symbol next to a section of text, you
must pay particular attention when reading through the text and not
carry out any operations of which you are unsure. This is to avoid
damage to the machinery or other equipment.
This symbol means Tip! You can get tips and advice on ways
to make operating your machine or associated equipment easier,
and to avoid wear. If you see this symbol next to a section of text,
you should read through the text to make your work easier and to
extend the service life of the machine.
1.4. Transportation
The machine is best transported secured to a load pallet.
1.5. On delivery
The following items are included on delivery. Contact your retailer
if anything is missing.
• Grinder
• Manual
• Locking key for control cabinet
• Hammer EZ system
• Splash guard
• Electrical cable with contact
• EZ Grinding holders
• Upper belt (spare part)

HTC 420 VS Introduction
2.0 3
1.6. Unpacking the machine
Warning!
Read through the safety instructions and the manual carefully
before use.
• Check carefully to see if the packaging or machine has
been damaged during delivery. If there are signs of damage,
contact your retailer and report the damage. Report any
external damage to the transport company as well.
• Check that the delivery matches your order. If you have any
questions, contact your retailer.
1.7. Machine name plate
The model number and serial number are shown on the machine
name plate. This information is required when ordering spare parts
for the machine. Use the space below to make a note of the model
number and serial number for future reference.
MODEL NUMBER _________________________________
SERIAL NUMBER__________________________________
1.8. Handling and storage
The machine should be stored in a heated, dry area when not in use.
Otherwise the machine may be damaged by condensation and cold.
1.9. Vibrations and noise
Warning!
Always wear hearing protection when using the machine.
The machine is tested in accordance with ISO 8662-4 and ISO
11202 with regard to vibrations and noise. The average value
is 0.65 m/s² for vibrations in connection with acceleration. The
average value for the sound level when rough grinding concrete is
97dB. This value varies depending on the choice of tool and the
type of floor.

Safety HTC 420 VS
4 2.0
2. Safety
2.1. General
This chapter contains all the warnings and observations that should
be taken into consideration for HTC 420 VS.
2.2. Warnings
Warning!
The machine may only be operated or repaired by personnel who
have completed the required practical and theoretical training
and who have read this manual thoroughly.
Warning!
Always use the machine in an environment where there is no risk
of explosion and fire. Find out and follow the relevant fire safety
regulations when grinding.
Warning!
Secure the area around the machine. No unauthorised persons
should be within a 15-metre radius of the machine. If loose objects
get under the grinding head, these may be flung out and cause
personal injury.
Warning!
Use safety equipment such as shoes with steel toecaps, goggles,
protective gloves, a mask and hearing protection.
Warning!
The machine may only be started with the grinding head lowered.
The rotating disc must be touching the floor and the right tool
must be fitted.

HTC 420 VS Safety
2.0 5
Warning!
After grinding, the tools will be very hot. Tip the machine back
and allow it to stand for a short while. Use protective gloves when
removing the tools.
Warning!
When changing tools or making repairs, the power to the machine
must be disconnected.
Warning!
The machine may only be used and moved over flat surfaces.
There may be a risk of crushing if the machine begins to roll.
Warning!
The machine must be connected to a residual current device.
Warning!
The machine may only be used when the splash guard is fitted.
2.3. Observations
Note!
The machine may only be used for grinding and polishing unhewn
stone, terrazzo, concrete, other materials specified in this manual
or material recommended by HTC.
Note!
Only original tools and spare parts from HTC may be used for the
machine, otherwise the CE mark and warranty will be invalid.

Safety HTC 420 VS
6 2.0
Note!
The instructions in this manual must be followed in order for the
CE mark to be valid.
Note!
The machine may only be lifted using the intended lifting eye.
Note!
The machine is best stored in a warm (above zero), dry area when
not in use.
Note!
If the machine is stored in a cold area (below zero), it must be
stored in a warm area (above zero) for at least two hours before
use.
Note!
When dry grinding, a suitable dust extractor should be used.
Contact HTC for model recommendations.
Note!
After removing glue and wet grinding, always lift up the grinding
heads so that they do not stick to the floor and damage machine
components and the floor when restarting.
Note!
When wet grinding, the water tank must be filled with water. Only
cold water with no chemical additives may be used.

HTC 420 VS Machine description
2.0 7
3. Machine description
3.1. General machine description
The machine is built around a number of main components - see
Figure 3-1 on page 7 and Figure 3-2 on page 8. It has
three motor options: 230 V 1-phase (EU), 400 V 3-phase (EU) and
115 V 1-phase (US).
The machine is built around a chassis with wheels. The motor with
a rotating grinding unit is attached to the bottom of the chassis,
so that there is some movement between the chassis and motor
package.
The handle can be set in a number of different tilt positions. Choose
a position that best suits you.
The grinding cover has a connection for an external suction hose
used for dry grinding.
The machine can easily be equipped with a large number of tools,
depending on the material to be ground. For the different tools, see
HTC’s Product Catalogue under the Grinding Guide tab.
7
6
5
4
3
1
2
8
9
Figure 3-1 Machine front
1. Suction hose

Machine description HTC 420 VS
8 2.0
2. Wheels
3. Splash guard
4. Grinding cover
5. Lifting handle for grinding head
6. Motor
7. Lifting eye for machine
8. Water tank
9. Adjustable handle
4
3
2
1
Figure 3-2 Machine rear
1. Control panel
2. Electrical connection
3. Extraction connection
4. Control cabinet

HTC 420 VS Machine description
2.0 9
3.2. Description of controls – Control
panel
The picture below shows the machines control panel:
Figure 3-3 Control panel
1. Power - Standby indicator: Indicates that the
machines functions have been activated. Lit
when the Power knob (7) is turned to “I”.
2. Overload - Overload indicator: Lights up to
indicate that the machine is using too much
power. If this is ignored, the power supply to
the motor will be interrupted and an error code
generated.
3. Reset - Resetting the electronics: If the
machine experiences an error, it may be
necessary to reset it. Turn the Grinding knob
(5) to “Reset” to reset all electronics. The
knob automatically returns to the central
position once it is released. Any error code is
shown on the display in the control cabinet.
4. FWD - Forward: Turn the Grinding knob (5)
to “FWD” to start the machines grinding discs.
5. Grinding - “Reset” (3) and “FWD” (4) knob.
6. Speed - Rotation speed: Regulates the rotation
speed of the machine’s grinding discs.

Machine description HTC 420 VS
10 2.0
7. Power - Start/stop the machines functions:
Turn the knob to “I” to activate the machines
functions and prepare for start. Turn the knob
to “O” to switch off the machines functions.
8. EM-Stop - Emergency stop switch: Press the
switch in an emergency to turn off the power
to the machine.

HTC 420 VS Operation
2.0 11
4. Operation
4.1. General
The following section describes how to change tools and how to
operate the grinder. This section does not deal with the technical
aspects of grinding, such as selection of grinding tools, etc. For
choice of tools, see HTC’s Product Catalogue under the Grinding
Guide tab.
Warning!
The machine may only be operated or repaired by personnel who
have completed the required practical and theoretical training
and who have read this manual thoroughly.
Warning!
Always use the machine in an environment where there is no risk
of explosion and fire. Find out and follow the relevant fire safety
regulations when grinding.
Warning!
Secure the area around the machine. No unauthorised persons
should be within a 15-metre radius of the machine. If loose objects
get under the grinding head, these may be flung out and cause
personal injury.
Warning!
Use safety equipment such as shoes with steel toecaps, goggles,
protective gloves, a mask and hearing protection.
Warning!
The machine may only be started with the grinding head lowered.
The rotating disc must be touching the floor and the right tool
must be fitted.

Operation HTC 420 VS
12 2.0
Warning!
The machine may only be used and moved over flat surfaces.
There may be a risk of crushing if the machine begins to roll.
Tip!
Check the minimum recommended cable area before using an
extension cord. You will find the recommended cable area under
Technical data on page 38.