AEG Electrolux FM 6520K-an User manual

FM 6520K-an
949 601 802325 88-8480 rev. 4-343GB
INSTRUCTION BOOK

2
Your New Appliance
Thank you for purchasing an AEG appliance.
To enable you to use your new appliance efficiently and safely, please read this
instruction book carefully before installing or using the appliance, and retain for
future reference. Should the appliance be transferred to a new owner please
ensure this instruction book is left with the appliance in order that the new owner
can get to know the functions of the appliance and the relevant warnings.
If you require further assistance or advice, please contact our Customer Care
Department either by letter or telephone:
Customer Care Department
AEG Domestic Appliances
55-77 High Street
Slough
SL1 1DZ
Tel: [phone]*
* calls to this number may be recorded for training purposes
35

34
3
Contents Page no.
For the User
Your New Appliance ........................................................................................ 2
Safety Information .......................................................................................... 5
Product Description ........................................................................................ 6
Ceramic Hob .......................................................................................... 7
Cooking Zones ........................................................................................ 7
Electronic Control .................................................................................. 7
Before use ........................................................................................................ 8
Protect the ceramic Hob.......................................................................... 8
How to Use the Hob ........................................................................................ 9
Ceramic Hob .......................................................................................... 9
Finger Touch .......................................................................................... 10
Cooking Zones ........................................................................................ 10
Double Cooking Zones .......................................................................... 11
Residual Heat Indicator .......................................................................... 11
AUTOMAX ............................................................................................ 12
Safety Turn-off ........................................................................................ 14
Autostop .................................................................................................. 14
Activating the Child Safety Device ........................................................ 15
Minute Minder ........................................................................................ 17
Timer ...................................................................................................... 18
Choice of Pans ........................................................................................ 20
Advice and Tips for Using the Cooking Zones ...................................... 21
Cleaning and Maintenance of ........................................................................ 22
Aluminium .............................................................................................. 22
Ceramic Hob .......................................................................................... 22
What to do if .................................................................................................... 31
Service and Spare Parts.................................................................................. 33
Guarantee conditions ...................................................................................... 34

4
Contents Page no.
For the Installer
Unpacking ........................................................................................................ 23
Technical Data.................................................................................................. 24
Installation........................................................................................................ 25
Mounting .......................................................................................................... 26
1... 2... Step by step
Safety information
Hints and tips
Environmental information
How to read the operating instructions
The products are continuously being developed and it may occur that some product specifications
are changed after this instruction book was printed. We therefore have to make reservation for any
changes or printing errors.
33

32
Exclusions
This guarantee does not cover:
· Damage or calls resulting from transportation, improper use or neglect, the
replacement of any light bulbs or removable parts of glass or plastic.
· Costs incurred for calls to put right an appliance which is improperly
installed or calls to appliances outside the United Kingdom.
· Appliances found to be in use within a commercial environment, plus those
which are subject to rental agreements.
· Products of AEG manufacture which are not marketed by AEG.
European Guarantee
If you should move to another country within Europe then your guarantee moves
with you to your new home subject to the following qualifications:
· The guarantee starts from the date you first purchased your product.
· The guarantee is for the same period and to the same extent for labour and
parts as exists in the new country of use for this brand or range of products.
· This guarantee relates to you and cannot be transferred to another user.
· Your new home is within the European Community (EC) or European Free
Trade Area.
· The product is installed and used in accordance with our instructions and is
only used domestically, i.e. a normal household.
· The product is installed taking into account regulations in your new country.
Before you move please contact your nearest Customer Care centre, listed below,
to give them details of your new home. They will then ensure that the local
Service Organisation is aware of your move and able to look after you and your
appliances.
France Senlis [phone]
Germany Nürnberg [phone]
Italy Pordenone [phone]
Sweden Stockholm [phone]
UK Slough [phone]
5
Safety Information
Keep an eye on children when the
hob is in use. Pans get very hot
when used and remain warm for
some time after the hob has been
turned off. Never let children touch
or play with the controls.
Never leave the hob unattended
when deep fat frying, or heating fats
and oils. In the event of fire turn off
all controls and if you have a cooker
hood this must be turned off as well.
Never leave paper, dish cloths, alu-
minium foil or any other easily ignit-
ed materials close to the
hob. A hot hob can cause foil, plastic
or paper to melt or burn.
Put out flames with a lid, and
never use water.
Check that the hob is turned off
when not in use.
The hob is intended for domestic use
only. If it is used in any other way
there is a risk of accidents.
Children
Use
For reasons of hygiene and safety
the cooking zones must be kept
clean. Grease and spilt food liberate
smoke when heated and may at
worst cause fire.
Service and repair must be per-
formed by our service organisation
or an organisation approved by us.
Only spare parts supplied by our
service organisation may be used.
Make sure the packaging is disposed
of in such a manner that children
cannot access the used packaging.
The product may only be installed
by an authorised electrician or a per-
son authorised by the manufacturer.
Work performed by an unauthorised
person may lead to injuries or build-
ing damages and deteriorate the
functionality of the product. When
installing make sure the cord does
not get jammed.
Cleaning and Maintenance
Service
Unpacking
Installation
Help prevent accidents when dispos-
ing of the product. Remove the cable
from the wall plug and cut off the
cable close to the product.
Disposal

6
Product Description
1. Double cooking zone Ø 120 / 180
mm, 700 / 1700 W.
2. Single cooking zone 140 mm,
1200 W.
3. Single cooking zone 140 mm,
1200 W.
4. Double cooking zone Ø 210 / 140
mm, 2200 / 1000 W.
5. Control panel.
1 3
2 4
5
3221
54
6
66 6
22 22 22333
4
Control Panel
1. On / off
2. Setting of steps
3. AUTOMAX
4. Double cooking zone
5. Child safety
6. Display for setting cooking zones
31
Customer Care
For general enquires concerning your AEG appliance or for further information
on AEG products, please contact our Customer Care Department at the address
below or visit our website at www.aeg.co.uk
Customer Care Department
AEG Domestic Appliances
55-77 High Street
Slough, Berkshire
SL1 1DZ
Tel [phone]*
*calls to this number may be recorded for training purposes
GUARANTEE CONDITIONS
Standard guarantee conditions
We, AEG, undertake that if within 12 months of the date of the purchase this
AEG appliance or any part thereof is proved to be defective by reason only of
faulty workmanship or materials, we will, at our discretion repair or replace the
same FREE OF CHARGE for labour, materials or carriage on condition that:
· The appliance has been correctly installed and used only on the electricity or
gas supply stated on the rating plate.
· The appliance has been used for normal domestic purposes only, and in
accordance with the manufacturer’s operating and maintenance instructions.
· The appliance has not been serviced, maintained, repaired, taken apart or
tampered with by any person not authorised by us.
· All service work under this guarantee must be undertaken by a Service Force
Centre. Any appliance or defective part replaced shall become the
Company’s property.
· This guarantee is in addition to your statutory and other legal rights.
· Home visits are made between 8.30am and 5.30pm Monday to Friday. Visits
may be available outside these hours in which case a premium will be
charged.

30
In the event of your appliance requiring service, or if you wish to purchase spare
parts, contact your local AEG Service Force Centre by telephoning:
08705 929 929
Your call will automatically be routed to the Service Centre covering your post
code area.
For the address of your local Service Force Centre and further information about
Service Force, please visit the website at www.serviceforce.co.uk
In-guarantee customers should ensure that the recommended checks under the
heading “What to do if..” have been made as the engineer will make a charge if
the fault is not a mechanical or electrical breakdown.
Please note that proof of purchase is required for in-guarantee service calls.
Help us to help you
Please determine your type of enquiry before writing or telephoning. When you
contact us we need to know:
1. Your name, address, post code and telephone number
2. Clear and concise details of the fault.
3. Date of purchase
4. The model and serial number
This information can be found on the rating plate.
Service and Spare Parts
7
Ceramic glass is insensitive to tem-
perature shock and very robust:
however it is not unbreakable.
Especially sharp and hard
objects that fall on the cooking sur-
face can damage it.
Ceramic hob
The vitroceramic hob has two single
and two double cooking zones.
When a zone is turned on it lights up
at different intervals depending on
which setting has been chosen. Even
at the highest setting the zone will
turn off occasionally to ensure that
the surface is not overheated.
The hob is equipped with an elec-
tronic control which secures that you
get a precise heat control of the
cooking zones.
The electronics have the following
functions:
- Setting of the double zones
- AUTOMAX, automatic parboil-
ing
- Safety turn-off
- Autostop. Automatic turn-off of
the cooking zones
- Child safety.
Cooking Zones
Electronic Control

8
Before Use
Protect the ceramic hob
Before using the hob for the first
time it must be cleaned for manufac-
turing residues such as dust, dirt etc.
Apply a protective coating on the
ceramic hob before you use it. This
way it becomes easier to clean the
glass and you prevent any spillage
from burning.
This is what you do:
1. Pour a few drops of the cleaning
agent supplied with the hob on
paper towel and rub it on to the
entire surface.
2. Polish the surface with a clean
cloth until it is dry.
29
Problem
The cooking zones do not heat suffi-
ciently….
The cooking zone will not turn on,
in the display is shown:
The cooking zone will not turn on,
in the display is shown:
Remedy
The pans must match the size of the
cooking zone. Check that the pans
have a plane bottom, e.g. by holding
a ruler to the bottom. Bring one litre
of water to the boil in a pot with lid.
Set the cooking zone at maximum
level.
The boiling time on a 12 cm cooking
zone is 25 minutes.
The boiling time on a 14 cm cooking
zone is approx. 13 min.
The boiling time on an 18 cm cook-
ing zone is approx. 10 min.
Child safety is activated. You can
either push jand another setting
simultaneously or you can de-acti-
vate the child safety, see section
“How to use….Child Safety”.
Autostop is activated. Push the k
key. The hob is now ready for use.
In-guarantee customers should ensure that the above checks have been made as
the engineer will make a charge if the fault is not a mecanicas or electrical brake-
down.
Please note that it will be necessary to provide proof of purchase for any in-guar-
antee service calls.

28
What to do if...
If the appliance is not working correctly, please carry out the following checks
before contacting your local AEG Service Force Centre.
IMPORTANT: If you call out an engineer to a fault caused by incorrect use or
installation, a charge will be made even if the aookuabce is under guarantee.
Problem
The hob does not work……..
The top plate gets hot……
The fuses keep blowing……
Remedy
Check that the hob is switched on.
Check the fault circuit-breaker in
the house. Check the fuse in the
hob and replace if necessary.
The top plate reaches a tempera-
ture of approx. 80°C. It may even
get hotter if you use pans which
do not have a plane bottom or do
not match the size of the cooking
zone.
Too many electric appliances may
be in use at the same time. If the
hob is connected to a 10 Amp fuse
group the risk of overloading is
considerable.
9
How to use
Ceramic hob
Never use a cracked ceramic
hob. On spillage liquid may
penetrate into live parts. Cut
the power to the devise and
contact our Service Centre
(see section “Service and
Spare Parts” for contact
phone number)
Never leave aluminium foil,
paper, plastic or the like on
the ceramic hob. A cooking
zone may cause the
foil/paper/plastic to
burn/melt.
Never leave frying, melting
of fat, paraffin or other
inflammables unattended. In
the event of fire all knobs
are to be set at 0 and if you
have a cooker hood this
must be turned off.
Smother the fire with a lid,
never use water.
Immediately scrape off
spillages using a glass
ceramics scraper. Spillage of
sugar or any foodstuff con-
taining sugar (jam, juice
etc.), melted plastics and
aluminium foil can damage
the ceramic hob.
Never place wet cooking utensils on
the ceramic hob. Make sure there is
no sand, sugar or salt on the utensil.
Sand may cause scratches, sugar and
salt may damage the ceramic hob.
Always dry off pans before placing
them on the ceramic hob.
The colour decoration on the
ceramic hob may wear off or be
scratched depending on the use.
Do not use the ceramic hob without
the aluminium list in place.
If you wish to use the ceramic hob
for setting down objects it must be
cold. If one or more of the cooking
zones are turned on while the
ceramic hob is used for setting down
objects there is a potential risk of
fire or melting. If a cooking zone is
used for setting down objects it may
cause damage to the ceramic hob.
Objects set down on the ceramic hob
must have a plane bottom/surface as
they otherwise may cause the
ceramic hob to be abnormally loaded
and thereby cause cracks / fractures
in the plate.

10
The keys are to be touched for mini-
mum 1 sec. before activation.
Finger Touch
Cooking Zones
The cooking zones can be adjusted
from 0-9, where 9 is the highest set-
ting.
1. Push the kkey.
2. Push lor mkey to adjust the
zone you wish to use.
The zones must be adjusted within
10 seconds or the hob turns off
again.
By pushing the mkey the cooking
zone is adjusted in steps from 0-9.
By pushing the lkey the cooking
zone is adjusted in steps from 9-0.
By continuously pushing the lor
mkey the adjustment goes faster -
the steps from 1-9 are run through.
Turn off a single zone by pushing
the l m keys simultaneously
until the display shows “0”.
Turn off all zones by pushing the k
key.
27
Overview of the outside
width of the units
180 mm
Downdraft
360 mm
Glass ceramic hob with 2 cooking
zones
Gas hob with 2 burners
Induction hob with 2 cooking zones
Grill
Grill / Fryer
Wok
580 mm
Glass ceramic hob with 4 cooking
zones
Gas hob with 4 burners
720 mm
Glass ceramic hob with 4 cooking
zones
Gas hob with 4 burners
Induction hob with 4 cooking zones

26
To optimise joints between the installed hobs, the gap between the ceramic hob
may be grouted with silicone:
1. Remove the aluminium panels from the hobs.
2. Apply a stripe of silicone to the gap between the two ceramic hob. Use only
the silicone supplied, as it is designed to tolerate the appliance’s high temper-
ature. (Fig. 1)
3. Splash a little soapy water (washing-up liquid) on the silicone stripe
4. Press the rubber block hard against the ceramic hob and pull it slowly from
back to front (Fig. 2)
5. Leave the silicone to harden until the next day.
6. Remove surplus silicone coating from the ceramic hob with the razorblade
supplied. Be careful not to damage the silicone in the gap. Run tools only
along the joint, never across it.
7. Polish the ceramic hob with the supplied cleaning product for ceramic hobs.
1
2
11
Double Cooking Zone
Residual Heat Indicator
In order to activate the double cook-
ing zone you have to do the follow-
ing:
1. Turn on the hob, push k.
2 Adjust the cooking zone, push
lor m.
3. Push 1.
To deactivate the double cooking
zone push 1.
Each cooking zone has a residual
heat indicator. When the cooking
zone is turned off the “H” is lit up in
the display until the cooking zone
has cooled. “H” is a warning that the
cooking zone is still hot.

12
Automax
With AUTOMAX you do not need
to turn down the temperature. When
using AUTOMAX the zone gets full
heat for a certain amount of time
where after the cooking zone auto-
matically adjusts to the setting you
have chosen.
To adjust AUTOMAX you have to
do the following:
1. Turn on the hob, push k.
2. Adjust the desired cooking zone
at the setting you wish to use.
3. Push N.
When AUTOMAX is coded the con-
trol lamp for “A” will light up.
To turn off AUTOMAX, you have to
push N.
The “AUTOMAX” chart on the fol-
lowing page gives guidelines for
suitable heat settings for
different types of cooking.
25
Silicone
Mounting:
When mounting several hobs together you must use a reinforcement beam
between each hob as well as the silicone supplied with the hobs (see fig.)
1. Cut a hole of the calculated size in the table top
2. Place the individual hobs upside down on a mat. Take care that the top side is
not scratched.
3. Mount the clamping fittings in the holes in the side of the base panels (see
fig.)
4. Place the first hob in the hole.
5. Apply silicone to the two corners joining the next hob (see fig.)
Use only the silicone supplied with the hobs as this is intended to tolerate the
high temperatures of the appliance.
6. Push a reinforcement beam up against the hob. Apply silicone on the rein-
forcement beam (see fig.)
7. Tighten the clamping fittings to the table top using a screwdriver.
8. Repeat the process for the other hobs.

24
Mounting more than one hob
Cutting out
The measurement of the selected combination is calculated in the following way:
Depth: 490 mm
Width:
1. Calculate the sum of all units’ width.
2. Subtract 20 mm from the total width.
Example:
A hob of 720 mm + a downdraft of 180 mm + a gas hob of 360 mm.
1. 720+180+360= 1260 mm
2. Width of the hole: 1260-20=1240 mm
Distance to Wall:
Min. 150 mm to flammable material.
Min. 50 mm to non-flammable material
4
9
0
m
m
Reinforcement beam
Distance to wall:
Min. 50 mm
( non-flammable material )
Distance to wall:
Min. 150 mm
(flammable material)
13
Settings
0
1
2
3-4
4
5-6
6-7
7
7-8
8
Type of cooking
Keep warm
Melting
Heating
Simmering
Low boiling
Boiling, brazing
Browning
Browning, frying
Browning
Examples
Keeping small portions warm.
Gelatine, chocolate, butter
.
Heating, hollandaise sauce etc.
Rice, dishes made from milk
.
Boiling of stock etc.
Continued boiling of vegetables
and potatoes
.
Liver, sausages, croutons, continued
frying of steaks
.
Fried eggs, pork chops, meatballs,
vegetables, potatoes
.
Pancakes, fries, steaks.
AUTOMAX Settings

14
Autostop
If by mistake one or more cooking
zones have not been turned off
Autostop will automatically turn off
the hob after a certain amount of
time. The time depends on the set-
ting. See below table. When
Autostop has been in function the
control lamp for kflashes.
Push kto reset Autostop.
Setting Max hours before auto
turn-off
6
5
4
1,5
1-2
3-4
5
6-9
Safety Turn-off
If one of the keys are activated for
more than 10 seconds (e.g. by a
child, pot spillage etc.) the hob is
automatically turned off.
23
Mounting
The unit may be mounted in any
type of kitchen worktop with a
thickness of 28 to 40 mm.
Cutting Out
When mounting the hob: Read the
instructions on this page. When
mounting this unit together with
other units: Read the instructions on
the next page.
For mounting this hob you need a
Philips screwdriver and the 4 clamp-
ing fittings supplied with this prod-
uct (see fig.).
Distance to Wall:
Minimum 150 mm to flammable
material. Minimum 50 mm to non-
flamable material.
1. Cut a hole in the table top
according to the measures stated.
See “Technical data”, “built-in
measurement”.
2. Place the unit upside down on a
mat. Take care that the top side is
not scratched.
3. Mount the clamping fittings in
the holes in the side of the base
panel (see fig.)
4. Place the unit in the hole and
tighten the clamping fittings to
the table top using a screwdriver.
Clamping fittings
Mounted clamping fittings

22
Installation
Electrical Installation
Connecting the Appliance
Installation may only be per-
formed by a qualified elec-
trician or a person autho-
rised by the manufacturer.
Work performed by an
unqualified person may
cause injury or damages to
property and deteriorate the
hob.
1-phase - Neutral - Earth
Cable type: 4 mm² HO5 RR-F
Installation must comply with any
special requirements laid down by
the local energy provider. The prod-
uct must be connected via an exter-
nal switch with a contact gap of at
least 3 mm. in all poles (May be the
main switch).
L
L1
N
3G4
L = 40 mm.
Cabel ties for min. 60°C
Min. Powersupply Cord:
HO5 RR-F 3G4 HAR
PE
If the power supply is dam-
aged or has to be changed, it
must only be changed by
Electrolux Service or an
organisation approved by
us.
15
Activating the Child Safety
Device
With the child safety function chil-
dren can be prevented from turning
on the hob unintentionally.
When the child safety is activated
you can still use the kkey and the
minute minder.
Activating the Child Safety Device
1. Turn on the hob, push the k
key
2. Push the
jkey for 3 seconds.
The control lamp for child safety
lights up.
If you try to turn on the hob when
the child safety is activated the con-
trol lamps for kand jwill light
up.
Push again on kto turn off.
To use the hob when the child safety
is activated do the following:
1. Push the kkey.
2. Push the jkey and the key you
wish to use simultaneously.
The child safety is disengaged while
the hob is in use. When the hob is
turned off the child safety is auto-
matically activated.

16
De-activating the Child Safety
1. Push the kkey.
2. Push the
jkey for 3 seconds.
The control lamp for child safety
turns off.
21
Technical Data
Model FM 6520K-an:
Product measurements:
Width: 580 mm
Depth: 520 mm
Height: 49 mm
Total power: 6300 W
Build-in measurements:
Width: 560 mm
Depth: 490 mm
Height: 38 mm
Measurements / power
Front left 140 mm 1200 W
Front right 140/210 mm 1000/2200 W
Rear left 120/180 mm 700/1700 W
Rear right 140 mm 1200 W
This unit is labelled to indicate conformity with the lowvoltage directive
(73/23/EEC) and the EMC directive (89/336/EEC).

20
Unpacking
Any damages resulting from a trans-
port which you have not performed
yourself must be communicated to
the dealer within one week of receipt
of the product.
On the rating plate which is placed
on the back of the product you will
find the CE marking and the prod-
uct’s serial number. Write the serial
number on the front of present
instruction book so it is easily acces-
sible in the event of service.
All packaging can be recycled.
Contact your local authority if you
do not know where to dispose of the
packaging.
Check that the appliance has no
faults and is undamaged on delivery.
Transport Damages
Removal of Packaging
17
Choice of Pans
Pans used on the glass ceramics
must:
- Completely cover the cooking
zone, and may be slightly larger
than the cooking zone
- Have a plane bottom or at most
curve slightly inward (max. 1
mm) as the bottom on heating up
will curve outwards
- Be thick-bottomed
- Aluminium pans must minimum
have a 3,5 mm thick bottom
- Steel pans and frying pans must
minimum have a 5 mm thick bot-
tom
- Have a completely smooth or
finely patterned bottom
Check that the planeness of the pans
by placing it upside down on a table
top and holding a ruler on the bot-
tom of the pan. A concave as well as
a convex bottom prolong the cook-
ing time and increases the energy
consumption. If the diameter of the
bottom is too small the energy con-
sumption will increase and food
which boils over will burn and stick
to the cooking zone.
Pans with very shiny / light coloured
bottoms may result in a slightly
longer cooking time than Pans with
a lustreless / dark bottom.

18
Advise and Tips for Using the Cooking Zones
!The pans must cover the full
cooking zone. It is OK if it is
slightly larger. Remember small
portions also fit in a large pan.
!The bottom of the pan must be
plane - it is OK if it curves slight-
ly inwards. If the bottom is con-
vex the cooking time is pro-
longed considerably. A lopsided
bottom can increase the energy
consumption by 50%.
!Use tight-fitting lids on the pan.
Without a lid on the pan you use
3 times as much power.
!Save water: Use as little as pos-
sible water when boiling. Boil
potatoes and vegetables with 1, 2
or 3 decilitre of water.
Use 1 decilitre of water on the 14
cm cooking zones
Use 2 decilitre of water on the 18
cm cooking zone
Use 3 decilitre of water on the 21
cm cooking zone
!Put a tight-fitting lid on the
pan. Bring to the boil at the high-
est setting and turn down to the
lowest possible setting when
there is heavy steaming at the lid.
Calculate the cooking time from
when you turn down. Do not
check the potatoes/vegetables till
the cooking time has expired.
!Turn down immediately when
the liquid boils.
Chose the correct setting.
Start at the highest setting and
turn down as much as possible
without the foodstuff going off
the boil.
!Use the residual heat: Turn off
the cooking zone 5 minutes
before the cooking time expires.
!Use the hot cooking zone for the
next boiling.
!Defrost the food in the fridge
before cooking.
!Save energy by preparing food in
a pot on a cooking zone instead
of preparing the food in the oven.
By using below advise you
can save energy and ease
cleaning.
19
Cleaning and Maintenance
Carry out daily cleaning with a well
wrung-out cloth. For more stubborn
soiling, use a cloth or a soft plastic
sponge together with washing-up
liquid or all-purpose cleaner.
Never use metal cleaning pads,
metal wool, hard plastic sponges,
scouring powder, soft soap or other
abrasive or caustic cleaning agents.
Aluminium
Immediately scrape off any sugar or
sugary food stains (jam, juice etc.),
melted plastic and aluminium foil
from the hot plate. If the plate cools
before these materials have been
removed it may become damaged. A
stained plate reduces the heat trans-
fer between cooking zone and pan.
Dry off cooking zones with a damp
cloth with washing-up liquid. When
heavily stained you can do the fol-
lowing:
1. Remove stains etc. using the
ceramic hob scraper.
2. Make sure the ceramic hob has
cooled down. Use the cleaning
liquid supplied with the hob.
Follow the instructions on the
cleaning liquid.
Ceramic hob
3. Wipe the plate with a damp cloth
or kitchen paper. Stubborn stains
are removed by rubbing hard on
the stain with a cleaning liquid on
paper towel.
4. Using a damp cloth wipe off any
excess cleaning liquid
5. Wipe with a dry cloth.
Make sure that the ceramic hob is
dry when heated. A damp surface
can develop rainbow-like stripes
when heated.