Atmos Multi Series Release note

ATMOS MULTI version 2002 Page 1

ATMOS MULTI version 2002 Page 2

ATMOS MULTI version 2002 Page 3
Table of Contents
Section Page
Introduction 1
1. Installation Regulation 2
2. General Information 2
3. Technical Data 3
4. Schematic of Boiler 4
5. Operation and
Construction
6
qAppliance construction 6
qOperating principle 7
qControls and function 8
qUser's programme 9
6. Installation Requirements 9
§Gas supply 9
§Electrical supply 9
§Terminal location 10
§Flue system 10
§Condensate disposal 11
§Discharge pipes 12
§Existing systems 14
7. Boiler Installation 14
§Unpacking the boiler 14
§Minimum clearances 15
§Boiler location 15
§Wall mounting the boiler 16
§Connecting the flue system 17
§Connecting the c/heating 18
§Connecting the mains water 19
§Connecting the discharge pipes 20
§Connecting the domestic hot
water
21
§Connecting the gas supply 21
§Connecting the condensate
siphon
22
§Connecting the electrical supply 22
Section Page
8. Commissioning 25
§Filling the heating system 25
§Filling the domestic hot water 26
§Appliance operation 26
§System balancing 27
9. System Shutdown 28
§Central heating circuit 28
§Domestic hot water 28
§Draining the boiler 28
§Disposal of appliance 28
10. Inspection & Servicing 28
§Boiler pre-service inspection 29
§Auxiliary equipment 30
§Servicing the boiler 30
§Completion 32
11. Component Replacement 33
12. Malfunctions 37
Appendices.
1. Spare part list
2. Combined safety & condensate discharge
3. Fault finding
4. Guarantee stipulations

ATMOS MULTI version 2002 Page 4
Introduction
The Atmos Multi gas fired storage combination boiler
that meets the requirements of Statutory Instrument
'The Boiler (Efficiency) Regulations' and is deemed to
meet the requirements of:
qGas Appliance Directive 90/396 EEC
qEfficiency Directive 92/42/ EEC
qLow Tension Directive 73/23 EEC (modified from
93/68) and;
qElectromagnetic Compatibility Directive 89/396 EEC
(modified from 93/68)
Atmos Heating Systems declare that the materials used
in the manufacturer of this appliance are non-hazardous
and that no substances harmful to health are contained
within the appliance.
The Atmos Multi must be installed in accordance with
these instructions and the regulations currently in
force. Please read these instructions fully before
installation and leave with the boiler for future
reference.
Atmos Heating Systems accepts no responsibility for
unsatisfactory performance of the appliance or flue
arising from the failure to comply with these installation
instructions.
On completion of installation the appliance must be
commissioned and the following explained to the user:
qThe operating principle of the appliance
qThe appliance controls and display
qStarting up, filling and de-aerating the appliance
qShutting down and draining
qAnnual inspection and maintenance
Atmos Heating Systems have a policy of continuing
improvement in the design and performance of its s
products. The right is therefore reserved to vary
specifications without notice.
For advice or information contact Atmos Heating
Systems by telephone or e-mail.
Atmos Heating Systems is part of the Benchmark
scheme. All our boilers include the Benchmark
Logbook and we advise all our installations to be
carried out to Benchmark standards.

ATMOS MULTI version 2002 Page 5
1. Installation Regulations.
1.1 A qualified registered installer in accordance with
the Gas Safety (Installation and Use) Regulations;
October 1994 must only install this appliance. Failure to
install appliances correctly could lead to prosecution.
1.2.The manufacturer instructions must not be taken as
overriding statutory requirements.
1.3 The installation of this appliance must be in
accordance with the relevant requirements of the Gas
Safety (Installation and Use) Regulations 1984 as
amended, Building Regulations, Building Standards
(Scotland), lEE Wiring Regulations (BS 7671), Health
and Safety Document No.635 (Electricity at Work
Regulations) and local Water Authority bye laws.
1.4 Installation should also be in accordance with the
relevant recommendations contained within the current
versions of the following British Standards.
qBS 6798 Specification for installation of gas fired
hot water boilers of rated input not exceeding 60
kW.
qBS 5449 Central Heating for Domestic Premises.
qBS 5546 Installation of gas hot water supplies for
domestic purposes.
qBS 5440 Flues and Ventilation for gas appliances of
rated input not exceeding 60 kW. (Part 1 Flues).
qBS 5440 Flues and Ventilation for gas appliances of
rated input not exceeding 60kw (Part 2 Air Supply).
qBS 6891 Installation of low pressure gas pipework
installations up to 28mm (R1).
Reference should also be made to British Gas Guidance
Notes for the Installation of Domestic Gas Boilers.
1.5. To ensure that the installation will perform to the
highest standards, the system and components should
conform to any other relevant British Standards in
addition to those mentioned in these instructions.
1.6. For Installation in Ireland the appliance must be
installed in compliance with I.S.813 ‘Installation of gas
appliances’.
1.7. Asbestos and CFC’s are not used in the
manufacture of these products.
2. General Information.
2.1 The Atmos Multi is a wall mounted, fully automatic gas
fired condensing combination boiler designed to provide
'unvented' domestic hot water at mains pressure via an
integral hot water storage cylinder.
2.2 Classified as an 'Unvented hot water system' the
installation of the Atmos Multi falls within the scope of the
Building Regulations 1995 (Part G.). These require that a
competent person as defined in the Approved Document G3
must only undertake the installation of an unvented system.
2.3 For central heating applications the Atmos Multi is
suitable only for use on a fully pumped, pressurised, sealed
primary system with a design (cold)pressure of between 0.5
and 2.5 bar.
2.4 The boiler may be installed in any room or internal space
without the need for purpose made ventilation, although
attention is drawn to the current IEE Wiring Regulations with
respect to installation in a room containing a bath or shower.
In such installations, it must not be possible for a person
using the bath or shower to touch any mains electricity fed
switch or boiler control.
2.5 In areas where the temporary hardness of the supplied
water exceeds 200mg/litre, a proprietary in-line scale control
device such as the 'Hydroflow' (available from Atmos
Heating Systems) should be fitted in the cold feed to the
boiler.
2.6 Although fitted with an automatic air release valve it
should be ensured that the boiler's heat exchanger is not a
natural collecting point for air. Air vents must be fitted at the
highest positions of the heating flow and return pipes and at
any other point in the system where air is likely to collect.
2.7 The Atmos Multi is suitable to acceptpre-heated water
such as that supplied from solar panel installations.
2.8 To ensure economic use of domestic hot water, it is
recommended that pipe runs between the boiler and taps be
in 15mm copper, as short as possible and, where practical, be
insulated to reduce heat loss.
2.9 Where the boiler is intended for use on Propane gas the
boiler must not be installed in a room or internal space below
ground level.

ATMOS MULTI version 2002 Page 7
Natural Gas & Propane Natural Gas Propane
3.Technical Data
24/80
24 /
80 Plus
32 / 80 Plus
32 / 80 Plus
CONDENSING MODE (Return < 55°C)
Heat Output to radiators kW min
-
max
7·3
-
22·5
7·3
-
22·5
9·8
-
29
9·8
-
29·9
Maximum heat to radiators Btu/hr
76,800
76,800
99,000
102,000
Gross efficiency ma
x
-
min
98
-
91%
98
-
91%
98
-
91 %
98
-
91%
NON
-
CONDENSING MODE (80/60°C flow/return)
Heat Output to radiators kW min
-
max
6·9
-
21·5
6·9
-
21·5
9·3
-
27·6
9·3
-
28·5
Maximum heat to radiators Btu/hr
73,400
73,400
94,200
97,300
Gross efficiency max
-
min
93
-
87%
93
-
87%
93
-
86%
93
-
86%
Seasonal efficiency (Sedbuk certified) %
91 3
91·3
91
91
Gas flow rate m3/hr natural gas min/max
0 8
-
2·6
0·8
-
3·3
1·1
-
3·5
0.4
–
1.25
Flue gas temperature min/max
°
C
35/
100°C
35/100°C
40/110°C
40/110°C
HOT WATER SYSTEM
Maximum heat to hot water kW
17·4
26·4
27·6
28·5
Hot water flow rate maximum litres/min at 2bar
25
25
25
25
Reheat time from 10 to 60°C minutes
20
12
11
10
70% reheat time m
inutes
17
10
9
9
Hot water at 40°C instantaneously (litres)
133
133
133
133
Hot water per hour at 40°C (litres)
450
700
725
750
Hot water per hour at 40°C (gallons)
100
150
160
165
EMISSIONS
NOx (average) emission ppm
18
18
19
19
CO (average) emission ppm
10
10
20
20
GC Number
41
-
249
-
02
41
-
249
-
03
41
-
249
-
04
41
-
249
-
04
COMMON DATA
Hot water temperature setting range
60 to 70°C
Central heating setting range
60 to 90°C
Hot water tank capacity
80 litres
Primary water capacity
2 2 litres
Hot water expansion vessel capacity
5 litres
C/ heating expansion vessel capacity
8 to18 litres
Maximum supply pressure
12 bar
Electrical Connection
220/240V
Outlet pressure hot and cold water
3·5 bar
C
ONNECTIONS
Air supply pipe diameter
80 mm
Flue pipe diameter
80 mm
Heating flow and return
22 mm
Hot water outlet
15 mm
Cold water supply
22 mm
Gas pipe connection
½" BSPM
Safety Valve discharge connection
22 mm
Condensate discharge
drain connection
32 mm
Underfloor heating flow connection
½" BSPF
DIMENSIONS AND WEIGHT
Height
1080 mm
Width
525 mm
Depth
495 mm
Minimum distance above floor
600 mm
Weight empty
70 kg
Weight full
150kg

ATMOS MULTI version 2002 Page 8

ATMOS MULTI version 2002 Page 9

ATMOS MULTI version 2002 Page 10
5. Operation and construction
The Atmos Multi is a fully automatic, gas fired, high
efficiency central heating boiler providing unvented
domestic hot water at mains pressure via an integral 80
litre copper hot water storage tank.
5.1 Construction of the appliance
A heat exchanger consisting of three concentric
channels is positioned in the centre of the boiler's
integral hot water tank. (Fig.1).
qHot flue gas released from a fully modulating, pre-
mix burner positionedat the top of the heat
exchanger, is driven downwards through the heat
exchanger's middle channel.
qThe second surrounding channel is divided into
eight smaller central heating water channels, which
together promote the transfer of heat from the heat
exchanger to water within the boiler's primary
circuit.
qThe third surrounding channel is divided into
small air channels. These together with the
inner copper wall of the hot water tank forms a
double partition between the central heating and
stored hot water.
While the hot water tank is completelyinsulated by
means of insulation shell sections, the hot water tank
itself along with the boiler's other components is
housed behind a removable outer steel appliance
casing, constructed in such a manner to ensure the
enclosed appliance space is ventilated.
Operation of the Atmos Multi boiler is controlled and
monitored by an electronic control unit that sends and
processes information to and from the boiler's various
temperature and control components. Along with
controlling the boiler's operation the control unit also
provides a diagnostic programme that simplifies fault
finding by automatically sending a fault code to a
'Status/error code display ' window located on the
control unit's fascia.
Central heating & Hot water circuit
When there is a demand for domestic hot water or
central heating, the water within the boiler primary
circuit is pumped through the heat exchanger from the
bottom to top via the central heating water channels to
a three way valve.
If there is a demand for hot water only, water within the
primary circuit circulates through the heat exchanger
only.
If there is a demand for central heating only, the three-
way valve changes position allowing the heated
primary water to flow from the heat exchanger to the
central heating system.
Where there is a demand for both domestic hot water
and central heating the three-way valve stays in a mid-
position, supplying heated water to both systems.
Flue gas circuit
The burners combustion air fan drives hot flue gases
produced by the combustion process from the top to
the bottom of the heat exchanger. Cooling of the flue
gases occur as they flow through the flue gas channels
towards their point of exit. On cooling the water vapour
suspended within the flue gas condenses, transferring
its latent heat as sensible heat to the cooler water
within the heat exchanger. The resultant condensate

ATMOS MULTI version 2002 Page 11
then falls to the bottom of the heat exchanger where it
is automatically discharged via the boiler's condense
drain point.
5.2 Operating principle of the appliance
qNo heat demand
The appliance will carry out a self-test every 24
hours when the connected to an available
electrical supply. For this test the boiler's
integral central heating pump will run for 3
minutes and the three-way valve will switch to
central heating in order to prevent the pump
from seizing.
qMeeting the heat demand (continuous
comfort mode)
If there is demand for heating and domestic hot
water at the same time, the hot water demand
has priority over the heating demand. This is
achieved by constant regulation of the three-
way valve from the control unit. The
'continuous comfort' mode may be switched off
if not required.
The central heating is controlled using a
standard 24V room thermostat or modulating
room thermostat. The domestic hot water
temperature is controlled by a 'user' setting,
which is adjusted via the control unit.
qHeat supply
When there is a demand for central heating, the
boiler's integral central heating pump and
combustion fan are automatically switched on.
Burner ignition occurs on the combustion fan
reaching its regulated speed. If no flame signal
is detected after 5 seconds, three more attempts
for burner ignition will be made within a 15-
second period, after which the appliance will
shut down.
On a loss of flame the appliance will carry out
four restart attempts, after which the appliance
will shut down. If the temperature of the central
heating water reaches 90°C, the burner will
automatically be extinguished. The appliance
has an anti-cycling time of 3 minutes during
which the burner will not re-ignite. The anti-
cycling period may be changed via the control
panel to 6 minutes or alternatively, switched
off.
On reaching the heating demand the burner will shut
down and the central heating pump continues to run
for a further one-minute period after which, the three-
way valve will switch to domestic hot water heating.
The pump will then run in hot water heating mode for
20 minutes (Factory setting). The pump running
times may be adjusted to suit individual system
requirements (see separately available Atoms Multi
Service Manual).
An insufficient heating water flow rate will be
detected by the high limit thermostat, which on
activation will cause the appliance to shut down.
qCombustion
The appliance is equipped with a continuously
modulating burner. The burner's heat input may be
manually set to suit individual system requirements
by adjustment of the fan pressure via a mechanical
gas-air connection. The appliance heat input
automatically reduces as the central heating flow
temperature reaches 80°C or higher.
qMost Efficient Start
Most Efficient Start is a comfortable energy saver,
which ensures that the home is heated as efficiently
as possible. When there is a central heating demand
the appliance always starts heating the home on a
low burner heat input. The amount of time at which
the burner continues to operate at low input
depends upon the heating demand of the heating
system.
After either first connecting the appliance to the
power supply, resetting followingshut down or
following a 180 minute period with no heat demand,
the burner will operate on a low heat input for 3
minutes, thereafter it is self adjusting.

ATMOS MULTI version 2002 Page 12
5.3 Controls and function.
The function mode of the appliance and the
central heating water pressure are indicated on
the electronic control unit's front fascia (fig 2),
located at the bottom left of the appliance
qDiagnostic display (fig 2 (1))
The boiler's operating status is indicated on the
diagnostic display. The various status codes are
explained in table 1. A flashing display or letter
symbol indicates that a boiler malfunction or
appliance lockout has occurred. The procedure to
follow is given in Section 12 of these instructions.
qCentral Heating Display (fig 2 (4))
The central heatingdisplay may be set to indicate
either the central heating water pressure (factory
setting) or central heating water temperature. (See
'User's programme' page 9)
If the central heating water pressure is too low or
too high, a warning symbol ‘C’ is shown onthe
diagnostic display. Further information is given in
Section 12 of these instructions
qHot water button (fig 2 (6))
If required the heating of domestic hot water may be
switched off using the hot water button. Pressing
the button once will turn off the indicator light and
curtail the hot water demand.
qSet button (fig 2 (2))
The set button is used to initiate an integral
programme to allow changes to be made to the
boiler's factory settings and other installation and
service activities. To protect against accidental use
the set button has to be depressed for a period of 5
seconds before activation occurs. Further
information on this subject can be found in the
separately available Atmos Multi Service Manual.

ATMOS MULTI version 2002 Page 13
qReset button. (fig 2 (3))
A lockout situation following a malfunction is
cancelled using the reset button. The button is
also used to exit the 'User's programme'.
5.4 User's programme
Along with giving operation and fault status
codes down to component level the electronic
control also permitsthe manual setting of the
boilers operational perimeters.
While the factory set parameters are suitable
for 90% of installations, in some cases such as
the elderly, infirm or very young for example, a
lower radiator surface temperature or domestic
hot water temperature may be desirable.
The Atmos Multi in-built user's programme
allows the user or installer to tailor suit certain
operational perimeters such as the domestic
hot water temperature, to the end users
requirements.
Access to the user's programme is gained by
pressing the control unit's 'Set' button for a
period of 5 seconds until a letter 'b' appears in
the diagnostic display window. Incremental
scrolling through the operational perimeters is
then obtained by re-pressing the 'Set' button.
The current setting for the selected operational
perimeter appears in the central heating water
display window. Pressing the 'Hot water'
button enables the setting to be changed to the
required value.
The user programme is terminated
automatically after five minutes from when the
last input action was carried out. Alternatively,
exit from the programme is achieved by
pressing the 'Reset' button.
Operational perimeters accessible via the users'
programme are given in Table 2, the factory settings
being underlined.
Further information on setting operation perimeters
is given in the Atmos Multi Service Manual.
6. Installation Requirements.
6.1 Gas supply
The gas meter and supply pipe must be capable of
delivering the required quantity of gas to the boiler
(refer to Technical Data page 3) in addition to the
demand from any other appliances within the
property. On final connection of the gas supply to
the boiler, the properties complete gas installation,
including the meter, must be tested for gas
soundness and purged as described in BS6891.
6.2 Electrical supply
The boiler requires a 230/240 V~50 Hz mains supply
fused at 3amp
The Atmos Multi is supplied factory wired complete
with 1·2m of mains cable. All electrical connections
to the mains supplymust be made in full accordance
with the current I.E.E. regulations.
The boiler must be earthed and connected via a
double pole isolating switch fused to 3 amp or
alternatively, by the use of a 3 amp fused three pin
plug and unswitched shuttered socket outlet. The
point of connection must be readily accessible,
adjacent to the appliance and provide complete
electrical isolation for the boiler and control
system.

ATMOS MULTI version 2002 Page 14
6.3 Flue terminal clearances.
The flue terminal must be sited
with minimum clearance distances
as specified in figure 3.
Aterminal guard (available from
Atmos Heating Systems) must be
fitted if the terminal is sited less
than 2m above ground level.
Where the flue terminates within
1m of a plastic or painted gutter or
within 500mm of painted eaves
then protection should be
provided in the form of an
aluminium shield at least 1m in
length, fitted to the underside of
the gutter or painted surface.
Please note !
Due to the low flue gas
temperature, 'pluming' will occur
at the flue terminal. Care should
be taken to ensure that the
discharge plume will not cause
annoyance to the customer or
neighbours. It is generally
recommended that flues should
discharge vertically at roof level,
where pluming is not normally a
problem
6.4 Flue system.
The flue system must be installed
in accordance with BS5440:1.
Horizontal flue gas discharge pipe
runs must always be installed
with a minimum 0·5% incline
towards the point of termination.
This incline will prevent
condensation from gathering in
the flue gas discharge pipe, and
will also reduce the chance of
icicles forming over horizontal
pipe ends in extreme weather
conditions. On horizontal
terminations the air supply pipe
must be led to outside with a
minimum 0·3% angle to prevent
the ingress of rainwater. Similarly,
provisions should be made to
prevent the ingress of rainwater
into the air supply pipe on
vertical terminations.
Figure 3: Flue terminal locations
Depending upon the boiler location and flue configuration required, two
different flue systems are available for use with the Atmos Multi boiler:
q125/80mm concentric system for use on vertical roof systems up to
a maximum equivalent length of 64m, and;
q80/80 twin pipe system which enables separate air intake and flue
gas discharge pipes to be fitted to the appliance, allowing a
combined total equivalent flue length of 64m
The maximum equivalent flue length of the flue system must not be
exceeded. If exceeded the boiler will not malfunction but its heat-output
capacity will be reduced. The connected gas/air regulator will however,
always ensure optimum combustion is maintained.
Examples of various flueing options and configurations are given in
figure 4.

ATMOS MULTI version 2002 Page 15
Figure 4: Examples of flueing options.
The equivalent length of the required flue system's
configuration can be calculated from the resistance
factors given for the individual flue components in
table 3. In the worked example (fig 5) the maximum
permitted combined length for a 80mm dia. twin flue
is 64metres at a pressure of 100 Pa. Account has
already been taken of the resistance of the balanced
flue terminal. This can therefore be ignored in the
calculation.
Table 3. Flue resistance factors
Figure 5: Worked flue length example.
6.5 Condensate disposal.
Provisions must be made for the safe disposal of
condensate produced when the Atmos Multi is in
operation. The condensate drainage pipework must
be run in an acid resistant material such as plastic
waste pipe. Copper or steel pipe must not be used.
The pipework must incorporate a minimum 1:20
downward slope towards its point of termination,
which ideally should be an internal soil or waste pipe
to avoid the possible risk of freezing. Alternatively,
where this not possible the condensate may be
discharged into an external gulley or purpose-built
soakaway.
The condensate pipework must be protected against
freezing and any pipework external to the property
must be encased in waterproof insulation and be
restricted to a maximum length of 3m.

ATMOS MULTI version 2002 Page 16
6.5 Discharge pipes.
It is a requirement of Building Regulation G3 that any
discharge from an unvented system should be
visible at both the tundish and final point of
discharge. Where this is not possible or practical
however, the discharge must be clearly visible at one
of these locations.
The discharge pipe from the tundish should
terminate in a safe place where there is no risk to
persons in the vicinity of the discharge.
While it is permissible to combine the discharge
pipes from the Atmos Multi temperature & pressure
relief valve and expansion pressure relief valve, the
tundish and Atmos Multi boiler must be located in
the same space. The tundish must also be within
500mm of the combined temperature & pressure relief
valve and installed in a vertical position.
While a minimum 300mm of vertical discharge pipe
must exist below the tundish, the discharge pipe
itself should be of metal construction and, unless its
total equivalent lengthexceeds 9m, be one pipe size
larger than the nominal outlet of the combined
temperature & pressure relief valve.
Where the total equivalent length of the discharge
pipe exceeds 9m the pipe must be increased by one
pipe size for each additional 9m length. For example a
discharge pipe having an equivalent length of
between 9 and 18m must be two pipe sizes larger
than the nominal outlet of the combined temperature
& pressure relief valve, between 18 and 27m three
pipe sizes larger, and so on. Bends must be taken
into account when calculating the flow resistance.
See Figure 6 and Table 4 for a typical discharge
arrangement and worked example.
Note. An alternative approach for sizing discharge
pipes would be to follow BS 8700: 1987 Specification
for design installation, testing and maintenance of
services supplying water for domestic use within
buildings and their curtilages. Appendix E, section
E2 and tables 21.
The discharge pipe must be installed with a
continuous fall towards its point of termination,
which ideally should be below a fixed grating and
above the water seal in a trapped gully. Where this is
not possible or practical then the discharge pipe may
terminate either:
qAt low level discharge above external surfaces
such as car parks, hard standings, grassed areas
and so on, providing that termination is a
maximum of 100mm above the surface and a wire
cage or similar guard is fitted to prevent contact
with any discharge, while still maintaining
visibility, or;
qAt high level into a metal hopper and metal
down pipe with the end of the discharge pipe
being clearly visible or alternatively, onto a flat
roof capable of withstanding high temperature
discharges of water. Such termination however,
must not be within 3m of any plastic guttering
and the tundish must be clearly visible in order
to detect any occurrence of discharge.
In cases where a single common discharge pipe
serves a number of units, such as in a block of flats,
the number of units served should be limited to a
maximum of six. The common discharge pipe should
be at least one pipe size larger than the largest
individual discharge pipe to be connected.
Where the Atmos Multi is installed in a property
where discharge from the unit may not be apparent,
such as in the case of blind, infirm or disabled
people, then consideration should be given to the
installation of an audible electronically operated
device to warn when discharge takes place.
Combined Safety discharge and condensate pipe
Subject to the approval of the Local Building
Inspector, the Safety discharge pipe and condensate
discharge pipe may be combined into a single
common discharge pipe. A schematic layout for such
an arrangement is given in Appendix 2 of these
instructions.

ATMOS MULTI version 2002 Page 17
Worked example:
The example belowis for a G ½ temperature relief
valve with a discharge pipe (D2) having 4 No. 22mm
elbows and length of 7m from the
tundish to the point of discharge.
From Table 1
Maximum resistance allowed for a straight length of
22mm copper discharge pipe (D2) from a G ½
temperature relief valve is: 9.0m
Subtract the resistance for 4 No. 22mm elbows at
0.8m each =3.2m
Therefore the maximum permitted length equates
to 5.8mwhich is less than the actual length of 7m.
Therefore calculate the next largest size (28mm) .
Maximum resistance allowed for a straight length of
28mm-pipe (D2) from a G ½ temperature relief valve
is: 18m
Subtract the resistance for 4 No. 28mm elbows at 1.0
m each = 4m Therefore the maximum permitted
length equates to 14m.As the actual length is 7m a
28mm (D2) copper pipe will be satisfactory.

ATMOS MULTI version 2002 Page 18
6.6 Existing systems.
All re-circulatory water systems are subject to
corrosion unless an appropriate water treatment is
applied. To prevent the risk of corrosion sludge
accumulates within an existing system causing
boiler noise and circulation problems along with
possible pump and valve damage, existing heating
systems must be thoroughly flushed to ensure that
all sludge and debris is removed prior to installing
the boiler.
Where a cleaning agent is used for this purpose
only Sentinel X400 is recommended. Atmos Heating
Systems do not recommend the any other cleaning
agent. The use of non-recommended cleaning
agents will invalidate the boiler's guarantee.
Note. When after flushing and cleaning of the
system has taken place there is any possibility of
any debris remaining in the system, it is
recommended that a 'Y' strainer is fitted on the boiler
Return pipe.
7. Boiler Installation.
7.1 Unpacking
Due to the boilers dry weight of 75kg it is
recommend that either a sack barrow or two men are
employed to carry the boiler to its chosen position.
The boiler must be carried and stored horizontally
on the wooden pallet provided. Under no
circumstances must it be stored vertically.
The appliance is protected by a cardboard box and
delivered as standard with:
qMounting bracket
qFixing pack consisting of 2 wall plugs, 2 bolts
and 2 washers
qBurner inspection window
qAutomatic de-aerator
qSiphon
qTemplate
qGuarantee registration card, Operating
instructions and Installation instructions
In addition the boiler is supplied with;
qWRAC mains water kit including UV3 cold
water inlet manifold, an 8 litre blue expansion
vessel, safety valve and pipe connections and;
qRobokit sealed system expansion vessel
including wall bracket and safety valve.
Using a knife, cut open the bottom tray of the box
and remove the top box from the bottom tray (fig. 7).
Figure 7: Unpacking boiler
Check the appliance immediately after unpacking.
Any damage must be reported immediately to your
supplier.
The packaging consists of corrugated cardboard,
wood and cellulose oil, and can therefore be
recycled as waste paper. Do not throw away the
packaging, but ask the local refuse collection
service where it can be taken.
Remove the appliance casing to prevent accidental
damaged during installation as follows (fig. 8):
i) Remove the two screws 'a' of the control panel.
ii) Unclick the catches 'b' at the top and bottom of
the appliance and remove case by lifting upwards.

ATMOS MULTI version 2002 Page 19
Figure 8: Removing the appliance case.
7.2. Minimum clearances.
For servicing and maintenance purposes, a minimum
clearance of 600mm to the front, 150mm above,
750mm below and 100mm to either side of the boiler
case is required. (fig. 9 & fig 10)
Figure 9: Dimensions & minimum clearances
Figure 10: Dimensions & minimum clearances
7.3 Boiler location.
The Atmos Multi is not suitable for external
installations.
While the appliance itself is provided with integral
frost protection it must however, be installed in a
room that stays free of frost even in extremely cold
conditions. This is to prevent pipes or the safety
valves from freezing. If the selected room does not

ATMOS MULTI version 2002 Page 20
meet this requirement, measures must be taken to
protect the safety valves and pipes against freezing.
The appliance must be installed on a flat vertical
wall that is capable of taking the weight of the
boiler. Do not fix directly onto low load bearing or
plasterboard walls.
For low load bearing and plasterboard walls a
special designed mounting frame incorporating
support legs should be employed. Contact Atmos
Heating Systems for this optional item.
On a lightweight block wall, heavy duty Rawplugs
must be used in place of the supplied wall plugs and
bolts.
The boiler may be fitted on or adjacent to a wall
comprising of a combustible material without the
need for a special thermal insulation barrier.
Due to the appliance being self-ventilating, it
remains relatively cool during operation. Generally
there is no requirement to provide purpose made
ventilation to an airing cupboard or compartment in
which the appliance is installed
A cupboard or compartment used to enclose the
appliance must however, be designed and
constructed specifically for the purpose and comply
with Building Regulations. The cupboard or
compartment must also be of sufficient size to
permit access for inspection and servicing or
removal of the boiler.
7.4. Wall mounting the boiler
Taking into account the clearances required for
servicing and maintenance, tape the provided
template onto the chosen wall position, ensuring it
is level and the correct way up.
Mark the position of the fixing holes for the boiler
mounting bracket. Drill the fixing holes using a
16mm drill bit and fit the mounting bracket using the
supplied fixing plugs and bolts.
Fit the appliance onto the mounting bracket as
follows (fig. 11):
a. Place the mounting indication point level with
the top side of the mounting bracket and
position the corners of the back of the casing
level with each end of the mounting bracket.
b. Put the bottom of the boiler against the wall.
c. Carefully lower the appliance onto the wall
bracket.
Note!
A lifting handle with red plastic covers on each
end is provided for lifting the boiler onto the
mounting bracket. Do not lift with other parts of
the boiler, as it may cause damage. To comply with
Health & Safety Regulations, Atmos Heating
Systems recommend that the boiler be lifted into
position by the use of two men.
Figure 11: Mounting the boiler
Warning : The fixings supplied are suitable
only for brick or solid block walls. When full
the Atmos Multi weighs 150kg and must not
be fitted directly onto walls with low load
bearing capacities.