Ariston microGENUS II 24 MFFI, microGENUS II 28 MFFI, microGENUS II 31 MFFI User Manual

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End User
Manual

microGENUS II 24 MFFI
microGENUS II 28 MFFI
microGENUS II 31 MFFI

Country of destination: GB/IE

Dear Customer,
Thank you for choosing an ARISTON boiler.

We guarantee that your boiler is a reliable and technically sound product.
This 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 manual, the Management invites customers to inform

of any inaccuracies which they may find.

This will help to improve our service

TABLE OF CONTENTS

1. GENERAL INFORMATION

1. GENERAL INFORMATION page 2

Control Panel page 3

2. OPERA TING INSTRUCTIONS page 3

3. USEFUL INFORMATION AND TROUBLESHOOTING page 5

4. MAINTENANCE page 6

5. CHANGE OF GAS TYPE page 6

6. MECHANICAL TIME CLOCK page 6

7. Digital Programmer page 7

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.

MTS (GB) Limited support the
you how to use, a Log Book which will give you important information about your boiler,
and heating system. Please have this Log Book 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 :- [phone].

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 only for the purpose for which it is
designed. The manufacturer declines all liability for damage caused by improper or
negligent use.
Do not allow children or inexperienced persons to use the appliance without supervision.
If you smell gas in the room, do not turn light switches on or off, 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.

initiative. Your installer will give you, and show

Before any intervention within the boiler it is first necessary to isolate the electrical
supply by turning the external switch to “OFF”.

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CONTROL PANEL

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IJK

LEGEND:

A - On/Off Switch
B - Domestic Hot Water Temperature Adjustment
C - Central Heating Temperature Adjustment
D - Reset Button
E - Comfort Mode Selector
F - Hot Water (Summer Mode LED - Green)
G - Ignition/Overheat Lockout LED (Red)
H - Central Heating (Winter Mode) LED (Green)
I - Digital Display (Fault Code/Water Temperature)
J - Time Clock
K-Central Heating System Pressure Gauge

2. OPERATING INSTRUCTIONS

K

CAUTION

In the United Kingdom installation, start-up, adjustments and maintenance m ust be
performed by a CORGI Registered Installer in accordance with the installation
standards currently in effect, as well as with any and all local health and safety
standards i.e.. CORGI.

In the Republic of Ireland the installation and initial start up of the appliance must
be carried out by a Competent Person in accordance with the current edition of
I.S.813 “Domestic Gas Installations”, the current Building Regulations, reference
should also be made to the current ETCI rules for electrical installation.

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 “D”, make sure that
the pressure is at 1.5 bar when the system is off and cool. If the pressure is below the
minimum recommended value (1 bar). To refill the system, open the two black handles
connected to the silver flexible hose, once the pressure gauge “K” reads 1.5 bar close
the valves again.

NOTE:DO NOT UNDER ANY CIRCUMSTANCES USE THE APPLIANCE WITH THE PRESSURE GAUGE

READING ZERO.

- 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 to prevent any liquid from 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

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PL00 4D

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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 “M” and “N”
be closed. If lo w temperatures are e xpected, the boiler and system pipe w ork 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 Ser vice Centre.

IGNITION PROCEDURE

Tur n the selector knob “A” to the “I” position. After a short delay the display will indicate

n

o

” indicating that the boiler is ready to operate. The electronic control unit will ignite the

“

burner, without any manual intervention but in response to the request for Domestic Hot
Water or Central heating. If, after approximately 10 seconds, the burner has not ignited,
the boiler safety devices will shut off the gas and the display will

A

01

indicate the fault code
button “D” must be pressed and released. Should the boiler fail to
ignite a second time, check that the external gas cock is open “N”.
If the problem persists, contact an Authorised Service Centre.

. To reset the ignition system, the reset

A

PL00 7D

summer

PL00 9D

winter

PL00 9D

PL00 8D

PL00 8D

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

PL00 4D

D

PL00 6C

boiler will produce only Domestic Hot Water.
Using the knobs on the control panel, the user can select ‘winter’ or ‘summer’ operating
mode.
Keeping the knob “C” at the “

” position selects the ‘summer’

summer

operating mode, the symbol “ “ will illuminate. ‘Winter’ operating
mode may be selected by positioning the knob “C” between the
min. and max. settings. The symbol “

ADJUSTING THE HEATING

“ will illuminate.

C

winter

It is possible to set the temperature of the Central Heating system
by adjusting the knob “C”. By positioning the indicator some where
between min. and max., a temperature may be obtained which
varies from approximately 42˚C to about 82˚C.
The water temperature in the Central Heating circuit may be

C

PL00 7C

checked on the display.

EXTERNAL (ROOM) THERMOSTAT CONTROL

C

If an external (room) thermostat is installed, it is recommended that the temperature of
the Central Heating system be set by means of the “C” knob, leaving 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

C

B

Both in the winter and summer mode, the temperature of the Domestic Hot Water may be
adjusted by using the “B” knob. A deliver y 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.
The water temperature in the primary circuit may be checked on the display.

NOTE: Should the hot water temperature be insufficientm turn the thermostat

knob to maximum and reduce the flow rate at the tap. ( A high flow rate will
reduce the temperature.

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economy

ECONOMY/COMFORT MODE

The selector knob “E” 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.

confort

PL00 6D

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 pre-heated condition,
thereby allowing a quicker delivery of Domestic Hot Water when required.

C

TURNING OFF THE CENTRAL HEATING

PL00 8D

A

PL00 4D

3. USEFUL INFORMATION
AND TROUBLESHOOTING

To tur n off the Central Heating, rotate the “C” knob to the “

” position.

The boiler will stay in ‘summer’ mode, providing Domestic Hot Water on request.

TURNING OFF THE BOILER

To tur n the boiler off, rotate the selector knob “A” to the “0” position (OFF); the display
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.

BOILER SHUTDOWN SITUATIONS

The boiler is equipped with safety devices that intervene in certain situations and shut it
off. Most of these situations are signalled by means of the L.E.D.s and in some
circumstances the user may be able to remedy them.

SHUTDOWN DUE TO IGNITION FAILURE

This anomaly is indicated by “A 0 1 ” on the display. To reset the boiler, press and then
release button “D”.
At this point, the electronic ignition system will attempt to light the burner again.

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.

PL00 7D

PL05 5D

PL01 2D

SHUTDOWN DUE TO OVERHEATING

This anomaly is indicated by “A 0 3 ” on the display. The boiler has shutdown because
the safety thermostat detected that the boiler temperature has e

xceeded the maximum
limit.
To reset, wait until the boiler has cooled and press button

“D”.
If the safety thermostat operates on a frequent basis, contact one of our Authorised
Service Centres.

SHUTDOWN DUE TO INSUFFICIENT WATER CIRCULATION

This anomaly is indicated by “E 02” on the display.
One of the possible causes of this shutdown situation could be the lack of water in the
boiler or water circulation failure in the primary heating circuit.
Check the system pressure on the pressure gauge “K” and, if it

K

is less than 0.5 bar, try bringing the system pressure up to a
mean value of 1.0 bar by opening the water inlet valve as
instructed on page 3. Then reset by pressing button “D”.

OTHER SHUTDOWN SITUATIONS

Should a shutdown situation indicated on the display by the following letters and figures
occur, E04, E05, E06, E07, E08, E09, E20, E33, E34 contact one of our Authorised
Service Centres.

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If instead the display shows one of the shutdown situations indicated by the following
letters and figures, A64, A97, A98, A99, try resetting the boiler by pressing the reset
button “D”. If the boiler shuts off again, contact one of our Authorised Service Centres.

ANTI-FROST DEVICE

The boiler is fitted with a device which, in the event that the water temperature falls below
8

˚C the pump activates and runs until a temperature of 18˚C is attained. In the event that
the water temperature falls below 3˚C, the diverter valve switches to Domestic Hot Water
and the burner fires and runs on minimum power until a temperature of 33˚C is attained.
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

5. CHANGE OF GAS TYPE

6. MECHANICAL TIME CLOCK

UT011Ap

Schedule an annual maintenance check-up for the boiler with a CORGI registered
Service Engineer.
Correct maintenance always results in savings in the cost of running the system.

Our boilers are designed to function either with Natural Gas (methane) or L.P.G. gas. If
you need to changeover from one gas to the other, one of our Authorised Service Centres
should be contacted.

NOTE: the time clock is for central heating control only.

The time clock is provided with 96 switches, called riders, each of which covers a time
interval of 15 minutes (four per hour).
When a rider is switched from the inside (off setting) to the outside of the clock border (on
setting), the circuit is closed (switch on) for a period of 15 minutes and then the boiler
starts if the room thermostat (if installed) or the heating thermostat require heat (heating
function on).

EXAMPLE

To set the heating of your home in the time inter val from 7.00 am to 9.30 am and from

7.00 pm to 10.00 pm every day:

- rotate the outer ring of the clock in a clockwise direction until the correct time of day

(24h) lines up with the arrow on the clock (at approx. 2 o’clock position);

- under no circumstances should the minute hand be moved manually;

- make sure all the switches, i.e. the riders, are placed on the inside of the clock border;

- pull outward the riders for 7.00 am and 9.30 am, and then all riders between these two;

- repeat this for 7.00 pm and 10.00 pm.

Other heating intervals may be set in the same way.
The timer has approximately 150 hours of battery back up for power failure.

The clock is provided with a selector switch with three positions (see figure):

1. Position “I” CONSTANT: in this position, the clock circuit is always

closed (switch on), therefore the boiler will constantly be on and will only
shut off upon the request of the room thermostat (if installed) or the
heating thermostat;

2.

Position “O” HEATING OFF: in this position, the clock circuit is always

UT014A

open (switch off) and the boiler will therefore never ignite for heating;

UT014A

3.

“Central” Position

PROGRAMMING ACTIVE:

in this position, the

programming set by the user is active.

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7. DIGITAL PROGRAMMER

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h

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Day

Manual switch

Summer and
winter time
setting

Reset

Enter

weekday/s

Enter
the hours

Week-
days
flash

Enter
minutes

Enter

switching

times

Imput

time

Automatic Manual Continuous
Operation Operation Operation

The switching If the current You can only
times corres- switching mode is return to automatic
pond to the changed manually, mode from the
program the next switching continuously-ON
entered. time will be and continuously-
 carried out auto- OFF switching
 matically again modes by
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 entered switching key.
 program.

= ON = ON = Continuously ON

= OFF = OFF = Continuously OFF

Operating the time switch

The step marked with the symbol “

” are necessary to carry out a

switching program.

Preparing for Operation

Activate the “Res” switch (=RESET) to reset the time switch to its
default setting (activate using a pencil or similar pointed instrument). Do
this:

- every time you wish to “reset” the time switch

- to erase all switching times and the current time of day.
After approximately two seconds the following display appears:

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 = “Monday”..............7 = Sunday

- Release the “

” key.

Entering the switching times

You have 20 memory Iocations available. Each switching time takes up
one memory location.
Keep pressing the “Prog” key until a free memory location is shown in
the display “– –:– –”.
Programme ON or OFF with the “

” key:
“ ”= OFF; “ ”= ON
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 day(s) it is to be
carried out by using the “Day” key.
When the day seIection is left bIank, the programmed switching
instruction operates at the same time every day
1 2 3 4 5 6 = Monday – Saturday
1 2 3 4 5 = Monday – Friday
6 7 =Saturday – Sunday

Selection of single days: 1 = Mon. .............. 2 =Tues.

.

Save the switching time with the “

” key
The time switch enters the automatic operating mode and displays the
current time of day.

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Begin any further entry of a switching time with the “Prog” switch. If your
entry is incomplete, the segments not yet selected will blink in the
display. After programming is completed, and you return the time clock
to the current time display with the “ ” key, the time clock will not
activate any switching instruction required for the current time. You may
need to manually select the desired switching state with the “ ” key.
Thereafter, as the unit encounters further switching instructions in the
memory in real time, it will correctly activate all subsequent switching
instructions.

Manual Override Switch “

With the “ ” you can change the current setting at any time . The switching
program already entered is not altered.

Reading the programmed switching times

Pressing the “Prog” key displays the programmed switching times until the
first free memory location appears in the display “– – : – –”.

If you now press the “Prog” key once again, the number of free memory
Iocations will be displayed, e.g. “18”. If all memory locations are occupied,
the display “00” appears.

Changing the programmed switching times

Press the “Prog” key repeatedly until the switching time you want to change
is displayed. You can now enter the new data. See point “Entering the

switching times”.

”

Notes on storing switching times:

If you end your entry of the switching times by pressing the “Prog” key, then
the switching time you have entered will be stored and the next memory
location displayed.

In addition, a complete switching command is stored automatically after
around 90 seconds provided no other key is pressed. The time switch then
enters the automatic operating mode and displays the current time again.

Deleting individual switching times

Press the “Prog” key repeatedly until the switching time you wish to delete
is shown in the display. Then set to “– –” using the “h” or “m” key and keep
the “ ” key pressed down for around 3 seconds. The switching time is now
erased and the current time is displayed.

AM / PM time display

If you press the “+/-1h” and “h” keys at the same time, the time display
switches into the AM/PM mode.

Manufacturer: Merloni TermoSanitari SpA - Italy
Commercial subsidiaries: MTS (GB) Limited MTS Heating Limited

MTS Building Damastown Industrial Park
Hughenden Avenue Damastown Avenue
High Wycombe Mulhuddart
Bucks HP13 5FT Dublin 15

Telephone: [phone] Telephone: [phone]
Fax: [phone] Fax: [phone]
Internet: www.mtsgroup.com/uk Internet: www.mtsgroup.com/ie
E-mail: [e-mail] E-mail: [e-mail]

Technical Advice: 0870 241 8180 Technical Advice: [phone]
Customer Service: 0870 600 9888 Customer Service: [phone]

Cod. 099841853000