Ariston MicroCombi User Manual

Users
Manual

2

Dear Customer,

Thank you for choosing an ARISTON
boiler.
We guarantee that your boiler is a reliable
and technically sound product.
This Users 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 12 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 Users Manual, the Management

invites customers to inform

of any inaccuracies which they may find.

This will help to improve our service

3

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 12

4. MAINTENANCE page 15

5. CHANGE OF GAS TYPE page 15

6. TIME CLOCK page 15

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. GENERAL INFORMATION

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 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
on light 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 T emper ature max-min

Maximum-Minimum Heating Pressure

Built-in expansion vessel - Total capacity

DOMESTIC HOTWATER

Maximum-Minimum Temperature of
Water for Domestic Use
Working pressure max-min
Flow rate ∆T 35°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)
Nominal Pressure/Liquid Gas (G30-G31)

kW
kW

%

°C

bar

litres

°C

bar

l/min

gal/min

l/min

V/Hz

W
IP

mbar
mbar

25.6-11.0

23.7-9.6

92.5

82-42

3-0.7

6

54-36

8-0.2

9.7

2.2

2.5

230/50

135

X4D

20-25
30-37

23 kW

6

CONTROL PANEL

23 MFFI

FR019A

7

LEGEND:

A - On/Off button
B - Central heating temperature adjustment
C - Domestic hot water temperature adjustment
D - Heating system pressure gauge
E - Time clock
F - Central heating selector
G - Central heating L.E.D.(green)
H - Fume sensor L.E.D.(yellow)
I - Overheat and/or ignition failure (lockout) L.E.D. (red)
J - Ignition failure (lockout) and/or overheat reset button
K - ON/OFF L.E.D. (green)

8

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
“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.
Consult your installer for checking
and refilling the system.

D

UT013Af

9

- The outer panels of the units 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 heat exchanger.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

Press button “A”. The green L.E.D.
“K” 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.
“I” illuminates. To reset
the ignition system, the
reset “J” 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.
Press “F” button to
select winter mode. The
green L.E.D. “G” will
illuminate.

10

K

A

G

F

UT002A

UT003A

J

I

UT006A

ADJUSTING THE HEATING

It is possible to set the temperature of
the heating system by adjusting the
knob “B”.
By positioning the
indicator somewhere
between 1 and 9, a
temperature may be
obtained which varies
from approximately
40˚C to about 80˚C.

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 “B” knob, leaving

it at 7-8 position 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
“C” 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 1
and 9 settings.

11

B

C

UT004A

UT005A

12

TURNING OFF CENTRAL HEATING

To turn off the central
heating, press the “F”
button; the respective
green L.E.D. “G” will go
off. The boiler will stay in
summer mode, only
providing domestic water
on request.

TURNING OFF THE BOILER

T o turn the boiler off, press the button “A”;
the respective green L.E.D .
“K” 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.

3. USEFUL INFORMATION
AND TROUBLESHOOTING

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.
“I” will illuminate. In order to reset the
ignition, the button “J” must be
pressed and released. Should the
boiler fail to ignite a second time, check

G

F

K

A

UT003A

UT002A

13

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 boilers exchanger, the
thermostat shuts off the
boiler and the red L.E.D.
“I” illuminates.
To remedy this situation,
wait a few minutes to
allow the exchanger to
cool down, then press
and release the reset

button “J”.
If this situation occurs frequently,
contact an Authorised Service Centre.

SHUTDOWN DUE TO INSUFFICIENT

WATER CIRCULATION

If 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 “D” and if it is less
than 0.5 bar, consult your installer for
checking and refilling
the system.
If the boiler does not
start up again, contact
an Authorised Service
Centre.
If there are frequent drops in pressure
within the system, have a plumber

J

I

D

UT006A

J

I

UT006A

UT001A

14

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. “H” 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.

IMPORTANT!

If this situation occurs frequently,
contact an Authorised Service Centre.
so that they may check that the e xhaust
fumes are being expelled correctly and
that the area is ventilated properly.

ANTI-FROST DEVICE

If the water temperature goes below
3°C, the burner turns on at minimum
power in CH mode until the water in the
boiler has reached a temperature of
about 33°C. This function is only
activated when the boiler is operating
perfectly and

- the system pressure is sufficient;

- the boiler is powered electrically;

- gas is being distributed.

H

UT006A

15

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.

6. TIME CLOCK

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

UT011Ap

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 interval 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

16

UT014A

request of the room thermostat (if
installed) or the heating thermostat;

2. Position “O”
HEATING OFF: in
this position, the
clock circuit is
always open
(switch off) and the
boiler will therefore
never ignite for
heating;

3. “Central” Position
PROGRAMMING
ACTIVE: in this
position, the
programming set
by the user is
active.

17

UT014A

UT014A

TECHNICAL DATA

Ambient
temperature: - 10°C to + 55°C
Running
reserve: 150 h

(not for 1.5 VDC)

Shortest
switching time: 15 minutes
Programmable: Every 15 minutes

18

19

Cod. 2399841567000 Stampa: Bieffe Recanati

Manufacturer: Merloni TermoSanitari SpA - Italy
Commercial subsidiary: MTS (GB) LIMITED

MTS Building
Hughenden Avenue
High Wycombe
Bucks HP13 5FT

Telephone: [phone]
Fax:[phone]
Internet: http://www.mtsgb.ltd.uk
E-mail: [e-mail]

Technical Service Hot Line: [phone]