Ariston microGENUS 23 MI User manual

User’s
Manual

2
Dear Customer,
Thank you for choosing an ARISTON
boiler.
We guarantee that your boiler is a reliable
and technically sound product.
This User's Manual provides detailed
instructions and recommendations for
proper installation, use and maintenance.
Remember to keep this manual in a safe
place for future reference i.e. by the gas
meter.
Your local MTS Servicing Centre is at your
complete disposal for all requirements.
The guarantee on this appliance is
valid for 24 months from the first
day of installation.
Repairs to the electric, hydraulic
or gas circuits may be carried out
only by your local authorised MTS
Servicing Centre.
Every attempt has been made to avoid
errors of any kind
in this User's Manual, the Management
invites customers to inform
of any inaccuracies which they may find.
This will help to improve our service
GROUP

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TABLE OF CONTENTS
1. GENERAL INFORMATION page 4
Technical Information page 5
Control Panel page 6
2. OPERATING INSTRUCTIONS page 8
3. USEFUL INFORMATION
AND TROUBLESHOOTING page 14
4. MAINTENANCE page 16
5. CHANGE OF GAS TYPE page 16
6. TIME CLOCK page 17
IMPORTANT!
Please read this manual carefully.
For additional information, please consult the “Installation and Servicing
Instructions.”
Make sure to keep the manuals provided with the appliance so that they
can be used by the end-user, installer or our authorised engineer.

4
1.GENERALINFORMATION
MTS (GB) Limited support the
initiative.Your installer will give you, and
show you how to use, a logbook which will
give you important information about your
boiler, and heating system.Please have
this logbook to hand whenever you
contact a service engineer or us.
All CORGI Registered Installers carry a
CORGI ID card,and have a registration
number.Both should be recorded in
your boiler logbook.You can check
your installer is CORGI registered by
calling CORGI direct on :- (01256)
372300.
This is a combined appliance for the
production of central heating (C.H.) and
domestic hot water (D.H.W.).This
appliance must be used onlyfor the
purpose for which it is designed.The
manufacturer declines all liability for
damage caused by improper or negligent
use.
Do not allowchildren or inexperienced
persons to use the appliance without
supervision.
If you smell gas in the room, do not turn
onlight switches, use the telephone or
any other object which might cause
sparks.
Open doors and windows immediately to
ventilate the room.
Shut the gas mains tap (on the gas meter)
or the valve of the gas cylinder and call
your Gas Supplier immediately.
If you are going away for a long period of
time, remember to shut the mains gas tap
or the gas cylinder valve.
Before any intervention within the
boiler it is first necessary to cut off the
electrical power supply by turning the
external switch to “OFF”.
This manual may be kept in the front
panel of the boiler.

TECHNICAL INFORMATION
5
GENERAL DATA
Heating input max-min
Heating output max-min
Efficiency at Maximum Thermal Capacity (see
installation instructions)
CENTRAL HEATING
Operating Temperature max-min
Maximum-Minimum Heating Pressure
Built-in expansion vessel - Total capacity
DOMESTIC HOT WATER
Maximum-Minimum Temperature of
Water for Domestic Use
Working pressure max-min
Flow rate ∆T 25°C
Flow rate ∆T 35°C
Minimum flow rate
ELECTRICAL DATA
Electrical Supply/ Frequency
Power Consumption
Protection of Electrical System
CATEGORY
Nominal Pressure/Methane Gas (G20-G25)
Nominal Pressure/Liquid Gas (G30-G31)
kW
kW
%
°C
bar
litres
°C
bar
l/min
l/min
l/min
V/Hz
W
IP
mbar
mbar
25.6-11.0
23.8-9.7
92.9
82-42
3-0.7
6
56-36
8-0.2
13.6
9.7
2.6
230/50
140
X4D
20-25
30-37
23 kW 29.8-12.0
27.8-10.5
93.5
82-42
3-0.7
6
56-36
8-0.2
?
?
2.6
230/50
155
X4D
20-25
30-37
27 kW

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CONTROL PANEL
23 MI
23/27 MFFI

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LEGEND:
A - On/Off knob
B - Domestic hot water temperature
adjustment knob
C - Central heating selection
(winter) and temperature
adjustment knob
D - On/Off L.E.D. (green)
E - Fume sensor L.E.D. (yellow)
F - Ignition failure (lockout)
L.E.D. (red)
G - “Economy/Comfort”mode
selection knob
H - Ignition failure (lockout) and/or
overheat reset button
I - Overheat L.E.D. (red)
J - Low system water level
L.E.D. (red)
K - Central heating temperature
L.E.D (yellow)
L - Time clock
M - Heating system pressure gauge

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2. OPERATING INSTRUCTIONS
CAUTION
Installation, start-up, adjustments
and maintenance must be performed
by a competent person only, in
accordance with the current Gas
Safety (Installation & Use)
Regulations and the instructions
provided. Improper installation may
cause damage or injury to
individuals, animals and personal
property, for which the manufacturer
will not be held liable.
To ensure efficient and safe
operation it is recommended that
the boiler is serviced annually by a
competent person.
If it is known or suspected that a
fault exists on the appliance, it must
not be used until the fault has been
corrected by a competent person.
HELPFUL SUGGESTIONS
To get the most out of your boiler, we
have provided you with some useful
advice on proper use and
maintenance:
- Periodically check the system
pressure using the pressure gauge
“M”, make sure that the pressure is
between 1.0 and 1.5 bar (the blue
part on the gauge) when the system
is off and cool. The warning L.E.D.
“L”will indicate if the pressure is
below the minimum recommended
M

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value. Consult your installer for
checking and refilling the system.
- The outer panels of the unit's case
must only be cleaned with a damp
cloth. Do not use abrasive cleaners.
The control panel can be wiped with
either a damp or dry cloth. Spray
polishes must not be used on the
control panel surface or knobs. Care
must be taken in preventing any
liquid entering the appliance.
PRACTICAL TIPS
- If the water is very hard, it is
recommended that a water softener
be added to the system so as to
reduce the formation of limescale in
the boiler exchangers. This will
ensure that the efficiency of the unit
remains the same over time,
reducing gas consumption and
maintenance costs.
- If the boiler should be out of use for
a prolonged period, it is
recommended that the electrical
power supply be disconnected and
that the external gas cock be closed.
If low temperatures are expected,
the boiler and system pipe work
should be drained in order to prevent
frost damage.
- To improve comfort and take full
advantage of the heat produced by
the boiler, it is recommended that an
external (room) thermostat be
installed.
- It is good practice to clean and
service the appliance and central
heating system every year.
Call an Authorised Service Centre.

IGNITION PROCEDURE
Turn the selector knob “A”to the “J”
position. The green L.E.D. “D”will
illuminate indicating that the boiler is
ready to operate. The centralised
electronic control unit will ignite the
burner, without any manual intervention
but in response to the request for
domestic hot water or heating. If, after
approximately 10 seconds, the burner
has not ignited, the boiler safety
devices will shut off the gas and the red
L.E.D. “F”illuminates. To reset the
ignition system, the reset “H”must be
pressed and released. Should the
boiler fail to ignite a second time, check
that the external gas cock is open.If the
problem persists, contact an
Authorised Service Centre.
WINTER AND SUMMER
OPERATING MODES
In the ‘winter operating mode’, the
boiler will produce both central heating
and domestic hot water. In the ‘summer
operating mode’, the boiler will produce
only domestic hot water.
Using the knobs on the control panel,
10
F
DAH

the user can select winter or summer
operating mode. Keeping the knob “C”
at the “0”position selects the summer
operating mode. Winter operating
mode may be selected by positioning
the knob “C”between the min. and
max. settings.
ADJUSTING THE HEATING
It is possible to set the temperature of
the heating system by adjusting the
knob “C”. By positioning the indicator
somewhere between min. and max., a
temperature may be obtained which
varies from approximately 45˚C to
about 80˚C.
The water
temperature in
the primary circuit
may be checked by
means of the yellow L.E.D.s
“K”.
EXTERNAL (ROOM) THERMOSTAT
CONTROL
If an external (room) thermostat is
installed, it is recommended that the
temperature of the heating system be
set by means of the “C”knob, leaving
11
C
summer
C
winter
K

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it at max in order to
obtain the best
performance from
the boiler and to
allow the regulation
of the external
temperature to
function efficiently.
SETTING THE HOT WATER FOR
DOMESTIC USE
Both in the winter and summer mode,
the temperature of
the domestic hot
water may be
adjusted by using
the “B”knob. A
delivery
temperature for the water may be
chosen in a range from 36˚C to about
56˚C, depending on the flow rate of the
water and the position of the knob
between the min. and max. settings.
ECONOMY/COMFORT MODE
The selector knob
“G”allows the user
to choose the
economy mode
(position “E”) or the
comfort mode
(position “C”).
The economy mode
is the normal state
for the operation of
the boiler, since the domestic water is
heated up only when a tap is turned on.
C
B
G
economy
comfort

13
The comfort mode is a special
operating state, because the water
contained in the secondary exchanger
and in the primary exchanger is kept in
a preheated condition, thereby allowing
a quicker delivery of domestic water
when required. The latter is therefore
the more convenient choice.
TURNING OFF CENTRAL HEATING
To turn off the central heating, rotate
the “C”knob to the “0”position.
The boiler will
stay in summer
mode, just
providing
domestic water
on request.
TURNING OFF THE BOILER
To turn the boiler off, rotate the selector
knob “A”to the “0”position (OFF); the
respective green L.E.D. “D”will go off.
Close the gas cock located under the
boiler and turn the electricity supply
switch (located outside the boiler) to
the OFF position.
C
AD

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3. USEFUL INFORMATION
ANDTROUBLESHOOTING
BOILER SHUTDOWN SITUATIONS
The boiler is equipped with safety
devices that intervene in certain
situations and shut it off. Most of these
situations are communicated by means
of the L.E.D.s and at times the user
may be able to remedy them.
SHUTDOWN DUE TO IGNITION
FAILURE
In the event that
the automatic
ignition of the
burner has
failed, the red
L.E.D. “F”will
illuminate. In order to reset the ignition,
the button “H”must be pressed and
released. Should the boiler fail to ignite
a second time, check that the external
gas cock is open. If the problem
persists, contact an Authorised Service
Centre.
SHUTDOWN DUE TO OVERHEATING
In the event that the safety limit is
exceeded for the temperature of the
water in the boiler’s primary exchanger,
the thermostat shuts off the boiler and
the red L.E.D. “J”illuminates.
To remedy this situation, wait a few
minutes to allow the exchanger to cool
down, then press and release the reset
button “H”.
If this situation occurs frequently,
contact an Authorised Service Centre.
F
J
H

15
SHUTDOWN DUE TO INSUFFICIENT
WATER CIRCULATION
If the red L.E.D. “L”is
illuminated and the
boiler is off, one
possible cause for this
state is an insufficient
pressure of water in the system.
Check the system pressure on the
pressure gauge “M”and if it is less
than 0.5 bar, consult your installer for
checking and refilling the system.
Then turn off and turn back on the
boiler by means of the selector knob
“A”. If the boiler does not start up
again and the L.E.D. “L”remains
illuminated, contact an Authorised
Service Centre.
If there are frequent drops in pressure
within the system, have a plumber
check the heating system for possible
water leaks.
TEMPORARY SHUTDOWN DUE TO
DEFECTIVE DISCHARGE OF
EXHAUST FUMES
The boiler is fitted with safety devices,
which in the event of a defective
discharge of exhaust fumes,
automatically interrupts the gas supply,
thereby shutting off the boiler.
The shut-off of the boiler is temporary
and is indicated by the illumination of
the yellow L.E.D. “E”for a period of
about 15 minutes.
Once this time period has passed and
the discharge state of exhaust fumes
has returned to normal, the boiler
automatically turns back on.
L

IMPORTANT!
If this situation occurs frequently,
contact an Authorised Service Centre.
so that they may check that the exhaust
fumes are being expelled correctly and
that the area is ventilated properly.
ANTI-FROST DEVICE
The boiler is fitted with a device which,
in the event that the water temperature
goes below 5°C, the three-way diverter
valve switches to domestic hot water
and the burner turns on at minimum
power until the water in the boiler has
reached a temperature of about 50°C.
This device is only activated when the
boiler is operating perfectly and
- the system pressure is sufficient;
- the boiler is powered electrically;
- gas is being distributed.
4. MAINTENANCE
Schedule an annual maintenance
check-up for the boiler with a
competent person.
Correct maintenance always results in
savings in the cost of running the
system.
5. CHANGE OF GAS TYPE
Our boilers are designed to function
either with Natural Gas (methane) or
LPG gas. If you need to changeover
from one gas to the other, one of our
Authorised Service Centres should be
contacted.
16

Do this:
- every time you wish to “Reset”time
switch;
- to erase all switching times and the
current time of day.
Input time Enter minutes
Manual switch
Enter weekdays
Enter the hour
Weekdays blinks
Reset
Enter
switching time Summer and
winter time
setting
6. TIME CLOCK
The steps marked with the symbol 
are necessary to carry out a switching
program.
PREPARING FOR OPERATION
Activate the “Reset”
switch to reset the time
switch to it’s default
setting (activate using
a pencil or similar
pointed instrument).
17

18
ENTER CURRENT TIME AND
WEEKDAY
Keep the “”key pressed down.
During the summer time period press
the +/-1h key once.
Enter the hour using the “h”key.
Enter the minutes using the “m”key.
Enter the day using the “Day”key.
1 = Mon ....... 7 = Sun
Release the “”key.
The colon now blinks once a second.
.AM/PM TIME DISPLAY
If you press the “+/-h”and “h”keys at
the same time, the time display
switches into the AM/PM mode.
NOTE:If you keep the “h”and “m”keys
pressed down for more than 2 seconds,
the display will enter fast forward scroll
mode.
ENTERING THE SWITCHING TIMES
If your entry is incomplete, the
segments not yet selected will blink in
the display.
You have 20 memory locations
available. Each switching time takes up
one memory location.
Keep pressing the “Prog”key until a
free memory location is shown in the
display “-- : --”.

19
Program ON or OFF with the “”key:
“”= ON - “”= OFF.
Enter the hour using “h”; enter the
minutes using “m”.
If a switching command is to be carried
out every day (1 2 3 4 5 6 7) then store
using the “”key, otherwise select
the days it is to be carried out on by
using the “Day”key.
When the day selection is left blank, the
programmed switching instruction
operates at the same time every day.
1 2 3 4 5 6 7 Monday..... Sunday
1 2 3 4 5 6 Monday..... Saturday
1 2 3 4 5 Monday ..... Friday
1 2 6 7 Saturday ..... Sunday
1 Monday
..... (selection of single days)
7 Sunday
Store using the “”key or push
“Prog”key if you are going to continue
programming. The time switch enters
the automatic operating mode and
displays the current time of day. Begin
any further entry of a switching time
with the “Prog”switch.
If necessary, once you have finished
programming and have returned to the
current time display, by pressing

20
the “”button, the timer will not
automatically switch to the current
programmed status until the next timed
setting. You can put the timer into the
correct mode with the “”key.
= ON
= OFF
AUTOMATIC
OPERATION
The switching times
correspond to the
program entered.
= OFF
= ON
MANUAL
OPERATION
If the current switching
mode is changed manually,
the next switching time will
be carried out automatically
again according to the
entered switching program.
= ON
= OFF
CONTINUOUS
OPERATION
[ ]
You can only return to
automatic mode from
the continuously ON and
continuously OFF
switching modes by
pressing the “”key.
ADDITIONAL FUNCTIONS
Switching from summer time to winter
and vice versa.
Press the “+/-1h”key once.