Atmos InterSystem HE26 User manual

Atmos InterSystem
Installation & Servicing Instructions for HE26 & HE40C
(GC 41 249 05 & GC 41 249 07)
Atmos Heating Systems
West March
Daventry
Northants, NN11 4SA
Tel: [phone]
Fax: [phone]
e mail: [email protected]
internet: www.atmos.co.uk
Issue 01.11.11 (Main revision)

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© 2011 Atmos Heating Systems
The information provided applies to the product in the standard model. Atmos Heating
Systems can therefore not be held liable for any damage resulting from the product
specifications that deviate from the standard model.
The information provided has been compiled with the utmost care. However Atmos Heating
Systems cannot be held liable for any faults in the information nor for the consequences
thereof.
Atmos Heating Systems cannot be held liable for any damage resulting from the activities
carried out by third parties.
To be changed without prior notice
Building Regulations and the Benchmark Checklist
Building Regulations (England & Wales) require notification of the installation of a heating appliance in
a dwelling to the relevant Local Authority Building Control Dept. This can be achieved via a
Competent Persons Self Certification Scheme as an option to notifying the Local Authority directly.
Similar arrangements apply in Scotland and Northern Ireland.
Atmos Heating Systems is a member of the Benchmark Scheme and the Benchmark Checklist is
included at the back of these Instructions. The Benchmark Checklist provides a Commissioning
Checklist and Service Record to be completed by the Installer/ Service Engineer.
Benchmark places responsibilities on both manufacturers and installers.
The purpose is to ensure that customers are provided with the correct
equipment for their needs, that it is installed, commissioned and serviced in
accordance with the manufacturer’s instructions by competent persons and
that it meets the requirements of the appropriate Building Regulations. The
Benchmark Checklist can be used to demonstrate compliance with Building
Regulations and should be provided to the customer for future reference.
nstallers are required to carry out installation, commissioning and servicing
work in accordance with the Benchmark Code of Practice which is available
from the Heating and Hotwater ndustry Council who manage and promote
the Scheme. Refer to www.centralheating.co.uk for more information.

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TABL OF CONT NTS
1. Safety Regulations 7
1.1 General ....................................................................................................................................................................... 7
1.2 CH system................................................................................................................................................................... 7
1.3 Gas system ................................................................................................................................................................. 7
1.4 Electrical system ......................................................................................................................................................... 7
1.5 Domestic water system ............................................................................................................................................... 7
1.6 Flue discharge and air supply ..................................................................................................................................... 7
2. Description of the Appliance 8
2.1 General ....................................................................................................................................................................... 8
2.2 Operation .................................................................................................................................................................... 8
2.3 Operating conditions ................................................................................................................................................... 8
2.4 PC interface .............................................................................................................................................................. 10
2.5 Test programmes ...................................................................................................................................................... 10
3. Main Components 11
3.1 Accessories ............................................................................................................................................................... 12
4. Installation 13
4.1 Overall dimensions HE26 .......................................................................................................................................... 13
4.2 Overall dimensions HE40C ....................................................................................................................................... 14
4.3 Unpacking the appliance ........................................................................................................................................... 15
4.4 Additional dimensions ............................................................................................................................................... 15
4.5 Boiler location............................................................................................................................................................ 16
4.6 Mounting ................................................................................................................................................................... 17
4.7 Mount the appliance .................................................................................................................................................. 18
4.8 Fit the pipework cover (optional only for HE26) ........................................................................................................ 18
4.9 Condensate disposal ................................................................................................................................................. 19
5. Connections 20
5.1 Connect the CH system ............................................................................................................................................ 20
5.2 Connecting the gas supply ........................................................................................................................................ 21
5.3 Electrical connection ................................................................................................................................................. 22
5.4 General Flue Requirements ...................................................................................................................................... 25
5.5 Flue discharge and air supply ................................................................................................................................... 26
5.6 Roof outlet prefabricated chimney ............................................................................................................................ 32
5.7 Atmos MS System ..................................................................................................................................................... 33
5.8 Atmos Communal Flue System (CFS) ...................................................................................................................... 34
6. Commissioning 35
6.1 Fill and de-aerate the appliance and the system ...................................................................................................... 35
6.2 Commissioning of the appliance ............................................................................................................................... 36
6.3 System Shutdown ..................................................................................................................................................... 37
7. Setting and Adjustment 38
7.1 Directly via operating panel ....................................................................................................................................... 38
7.2 Settings through the service code ............................................................................................................................. 38
7.3 Parameters................................................................................................................................................................ 39
7.4 Setting maximum CH power ..................................................................................................................................... 40
7.5 Setting pump position ................................................................................................................................................ 40
7.6 Weather-dependent control ....................................................................................................................................... 41
7.7 Conversion to other gas type .................................................................................................................................... 41
7.8 Gas-air control........................................................................................................................................................... 41
7.9 Setting gas-air control ............................................................................................................................................... 42
7.10 Carbon monoxide : carbon dioxide ratio (CO/CO
2
ratio) ........................................................................................... 43
8. Faults 44
8.1 Display last fault code. .............................................................................................................................................. 44
8.2 Burner does not ignite ............................................................................................................................................... 45
8.3 Burner ignites with much noise ................................................................................................................................. 45
8.4 Burner resonates ....................................................................................................................................................... 46

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8.5 No heating (CH) ........................................................................................................................................................ 46
8.6 Reduced output ......................................................................................................................................................... 47
8.7 CH does not reach the correct temperature .............................................................................................................. 47
9. S RVICING TH BOIL R AND COMPON NT R PLAC M NT 48
9.1 SERVICING THE BOILER ........................................................................................................................................ 48
9.2 COMPONENT REPLACEMENT ............................................................................................................................... 49
10. Technical Specifications 52
10.1 Electrical diagram HE26 ............................................................................................................................................ 53
10.2 Electrical diagram HE40C ......................................................................................................................................... 54
11. C Declaration 55
NOTE The Benchmark Checklist & Service Record are included at the back of the Manual.

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This manual
Using this manual you can safely install and maintain this appliance.
Carefully follow the instructions.
In case of doubt contact Atmos Heating Systems.
Keep these instructions near the appliance.
Abbreviations and names used
Description
To be referred
to as
High Efficiency
HE
Atmos InterSystem wall
-
mounted gas heater
Appliance
Appliance with piping for central heating
CH system
Icons
The following symbols are used in this manual:-
CAUTION
Procedures that, when not carried out with due care,
may result in damage to the product or the
environment or in personal injury.
Service and technical support
For information about specific adjustments installation maintenance and
repair activities please contact:
Atmos Heating Systems
West March
DAVENTRY
Northants NNII 4SA
Tel: [phone]; fax: [phone]
Email: [e-mail]; internet: www.atmos.co.uk
nvironment
When the appliance needs replacement your installer
may
arrange for disposal. Should this not be possible then
make enquiries with your local council about the
possibilities for re-use or environmental-friendly processing
of the materials used or contact a scrap dealer about
disposal.
Various plastics and metals have been used in producing
the appliance. Also the appliance contains electronic
components that are electronic waste.
Intended use
The appliance as described in this documentation is intended for heating rooms
with a central heating system and if required heating hot water via an indirect
hot water tank. Any other use is outside the scope of intended use for this
appliance. Any liability for damage resulting from improper use shall not be
accepted.

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Atmos Warranty – Short version
1. Atmos Warranty covers any material construction or operation faults that are
found to be of original manufacturing origin. A full statement of the Atmos
Warranty can be found on www.atmos.co.uk.
2. Atmos boiler warranty is two years from date of invoice or 12 months from
date of installation whichever is the later. This warranty covers the cost of
replacement parts and associated labour. However the ignition & ionisation
probe and the glass fuse are excluded from this warranty. The warranty for
the heat exchanger is 10 years in total but this covers the cost of associated
labour only for the first two years from date of invoice.
3. There is no carriage charge for the delivery of replacement parts covered by
the warranty. Any alleged faulty part must be returned to Atmos carriage
prepaid. Carriage will be credited if the fault is found to be a manufacturer’s
fault.
4. The serial number of the boiler must be supplied with any warranty claim.
5. All products must be used in an appropriate application and manner. This
includes but is not limited to correct boiler sizing system design system
cleansing and use of corrosion inhibitors. If the boiler installed is a combi
boiler an approved water conditioner device must be fitted in areas where the
water hardness exceeds 200ppm as required by Building Regulations.
6. The Benchmark Checklist & Service Record found in the back of the
installation Instructions must be filled in. Failure to install and commission
according to the manufacturer’s instructions and complete the Benchmark
Commissioning Checklist invalidates the warranty.
7. The Warranty card must be completed and the signed Atmos copy must be
received within 14 days of installation together with a copy of the Benchmark
Commissioning Checklist completed by the installer. By signing the Warranty
card the buyer agrees that the goods have been delivered in a satisfactory
condition.
xceptions
8. In the event of full payment for a product not being received Atmos shall be
discharged from all further contractual or warranty obligations.
9. Surface and/or transport damage are outside the scope of this warranty.
10. Any warranty provision shall not apply if Atmos determines that the fault is
due to improper application use neglect accidental damage or injudicious
treatment non-observance of instructions contained in Atmos Manuals or due
to improper repair adjustment installation or maintenance or due to work
carried out by unqualified engineers. The warranty also lapses if the Atmos
boiler has not had a yearly service in accordance with instructions.
11. This warranty shall not apply if the fault is caused by scale failure or
abnormality of gas or water supply or impact of any external influence that
adversely affects the normal operation of the product. This shall include but
not be restricted to dehydration abnormal or high voltage and hard water.
12. Excluded parts are the ignition & ionisation probe and the glass fuse as these
are subject to wear and tear in normal use.

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1. SAF TY R GULATIONS
The appliance must be installed by a Gas Safe registered person in accordance with
the current Gas Safety (Installation and Use) Regulations. Failure to install
appliances correctly could lead to prosecution.
Atmos Heating Systems does not accept any liability for damage or injury
caused by not (strictly) observing the current safety regulations and instructions
nor by negligence while installing the Atmos InterSystem wall-mounted gas
heater and any accompanying accessories.
The manufacturer’s instructions must NOT be taken as overriding statutory
requirements.
The regulations are mentioned separately for the different disciplines.
1.1 General
The entire system should comply with the valid (safety) regulations as
mentioned in:-
• This installation manual.
• Gas Safety (Installation and Use) Regulations
• The appropriate Building Regulations.
• Health and Safety Document No 635 (Electricity at Work Regulations)
• The Water Fittings Regulations or local Water byelaws.
1.2 CH system
The entire system should comply with the valid (safety) regulations as
mentioned in:-
• BS 5449 Central Heating for Domestic Premises.
1.3 Gas system
The entire system should comply with the valid (safety) regulations as
mentioned in:-
• BS 6798 Specification for installation of gas fired hot water boilers of rated input not
exceeding 60 kW .
• BS 6891 Installation of low pressure gas pipework installations up to 28mm (R1).
• I.S.813 Installation of Gas Appliances (for installations in Ireland).
• British Gas Guidance Notes for the Installation of Domestic Gas Boilers.
1.4 lectrical system
The entire system should comply with the valid (safety) regulations as
mentioned in:-
• BS 7671 The IEE Wiring Regulations.
1.5 Domestic water system
The entire system should comply with the valid (safety) regulations as mentioned in:-
• BS 5546 Installation of gas hot water supplies for domestic purposes.
1.6 Flue discharge and air supply
The flue discharge and the air supply system should comply with:-
• BS 5440 Flues and Ventilation for gas appliances of rated input not exceeding 60 kW.
(Part 1 Flues and Part 2 Ventilation).

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2. D SCRIPTION OF TH APPLIANC
2.1 General
The Atmos InterSystem wall-mounted gas boiler is designed for delivering
heat to the water of a CH system and if required heating hot water via an
indirect hot water tank.
The air supply and flue discharge can be connected to the appliance by
means of two separate pipes or a concentric connection.
The appliance has its own wall mounting strip but can also be fitted to an
optional wall mounting frame that allows top connections. An optional pipe
mounting bracket for use with the wall mounting strip is available. These are
supplied separately.
The Atmos InterSystem wall-mounted gas boiler has the CE quality mark
and IP44 Protection class.
The appliance as delivered is suitable for natural gas (G20). A conversion kit
for propane (G31) can be supplied upon request.
2.2 Operation
The Atmos InterSystem wall-mounted gas heater is a modulating high
efficiency boiler. This implies that the power is adjusted to the heat demand.
In the aluminium heat exchanger is an integrated copper circuit.
The appliance has been provided with an electronic controller that controls
the fan with the heat demand from the heating system or the hot water tank
opens the gas valve and ignites the burner continuously monitors the flame
and controls it dependent on the power required.
2.3 Operating conditions
A code indicates the operating condition of the appliance on the service
display of the operating panel.
- Off
The appliance is not operating but there is electrical power. There is no
response to any demand for CH (heating or hot water tank). The frost
protection is active though. This means that the pump starts running and the
heat exchanger is heated when the temperature of the heat exchanger
drops to 5°C.
When the frost protection is activated code 7 appears (heating of the
heat exchanger).
Waiting position
The LED of the on/off button is on. The appliance is ready for responding
to the demand for CH (heating or hot water tank).

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0 Pump overrun
After CH operation the pump has an overrun. This overrun time is set to the
value according to parameter 8 (see §7.3; factory setting is 1 min). This setting
can be changed. Also the controller will automatically run the pump for 10
seconds once every 24 hours to prevent it from getting stuck. This activation of
the pump takes place at the time of the last heat demand 24hrs later. In order to
change this time set the room thermostat higher for a while at the desired time.
1 Required temperature reached
The controller can temporarily block the heat demand and stop the burner. This
blocking takes place because the required temperature has been reached.
When the temperature has dropped sufficiently the blocking is cancelled.
2 Self-test
The controller regularly checks the connected sensors. During the check the
controller does not carry out any other tasks.
3 Ventilate (Fan)
On starting the fan is first brought to the starting speed. When the starting
speed has been reached the burner is ignited. Code 3 is also visible after
stopping the burner when post-purge takes place.
4 Ignite
When the fan has reached the ignition speed the burner is ignited by means of
electric spark ignition. During ignition the code 4 appears. If the burner is
not ignited another ignition attempt is made after about 5 seconds. If the burner
has still not fired after the fourth ignition attempt the controller indicates a fault.
See §8.
5 CH operation
An on/off thermostat can be connected to the controller if necessary in
combination with an outside sensor. See the Electrical diagram §10.1 and
§10.2. When heat is demanded by a thermostat signal the fan runs (code 3 )
and the burner is ignited (code 4 ) followed by the CH operating condition
(code 5 ).
During CH operation the fan speed and hence the power of the appliance is
adjusted. This is done in such a way that the temperature of the CH water is
controlled towards the set CH supply temperature. In the case of an on/off
thermostat the CH supply temperature is set at the operating panel. In the
case of an outside sensor the CH supply temperature is determined by the
weather dependent control programmed in the controller.
During CH operation the demanded CH supply temperature is displayed on the
operating panel.
During CH operation the actual CH supply temperature can be read by
pressing the service button.
Note: Instead of an on/off thermostat an OpenTherm thermostat can be
connected to the controller as described in §5.3.1. In this case the desired CH
temperature is set by the thermostat. The minimum temperature and the
operation mode can be set with parameters [E] and [E.] (refer to §7.3).

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2.4 PC interface
The controller has an interface for a PC. With a special cable and
accompanying software a PC can be connected. This provision makes it
possible to follow the behaviour of the controller the appliance and the
heating system during a long period.
2.5 Test programmes
In the controller there is provision for putting the appliance into a test status.
By activating a test programme the appliance will become active with a
fixed fan speed without intervention of the control functions. The safety
functions remain active though.
Simultaneously press + and – to switch off the test programme.
Test programmes
Description of programme
Button
combinations
Display
reading
Burner on with minimum CH
power
"service" and "
-
"
“L”
Burner on with maximum
CH power
"service" and “+” (1x)
“h”
Burner on with maximum
power (set by parameter 4)
"service" and “+” (2x)
“H”
Switch off test programme
"+" and "
-
"
Current
operating
condition
2.5.1 Frost protection
The boiler has provision for protecting its heat exchanger as described
below.
NOT ! However to avoid the condensate freezing the boiler must be
installed in a FROST-FREE room.
•
In order to avoid freezing of the appliance (heat
exchanger) it has an appliance frost protection.
When the temperature of the heat exchanger drops
to 5ºC the burner will be activated and the pump
will start running until the temperature of the heat
exchanger reaches 10ºC.
Code 7 is given when the appliance frost
protection intervenes (heating heat exchanger).
• When the system (or a part thereof) can freeze a
frost thermostat should be installed in the area to
be protected. Connect this according to the wiring
diagram. See §10.1 and §10.2.
Remark
When the appliance is out of action ( - on the service display) the
appliance frost protection is still active. However there will be no response
to heat demand from an (external) frost thermostat.

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3. MAIN COMPON NTS
A
CH pump
M
Flue discharge (or concentric connection)
B
Gas valve
N
Connect
ing block / terminal list X
C
Clamping plate
O
Condensate discharge
D
Supply sensor S1
Q
Codensate trap
E
Return sensor S2
R
Heat exchanger
F
Fan
S
Controller o
perating panel and display
H
Pressure gauge
T
Ionisation/ignition probe
I
1m connecting ca
ble 230 V ~
U
Position type plate
J
Manual air vent
V
Expansion vessel (shown in broken lines
HE26 only
)
The HE40C does not have an expansion vessel
K
Sight glass and mirror
W
Pressure relief safety valve 3 bar
L
Air supply (left or right)
Additional Components supplied :-
Valve set (supplied separately with boiler)

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3.1 Accessories
Description
Part Ref
Pipe mounting bracket
• Connection supply and return 22 mm diameter
• Connection gas ½" female thread
• Mounting strip boiler
• Bag with fixings
092537
Rear
mounting frame for top pipe connection
092507
Bottom Pipework cover
(
H 26 only)
092527
Outside sensor for weather compensation
203
207
Conversion set to Propane (G31)
for H 26
075537
Conversion set to Propane (G31) for H 40C
075737
Intergas diagnostic
software incl. USB interface cable (for Installers)
090407

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4. INSTALLATION
4.1 Overall dimensions H 26
A=
CH flow
22 mm diameter
h=
670mm
InterSystem HE 26
B=
CH return
22 mm diameter
C=
Gas
15 mm diameter
H=
810mm
InterSystem HE 26
Z=
Flue gas outlet
80 mm diameter
F=
Condensate
32 mm dia (after
trap
25 mm dia flexible)
Y=
Air supply inlet
80
mm diameter

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4.2 Overall dimensions H 40C
A=
CH flow
22 mm diameter
h=
670mm
B=
CH return
22 mm diameter
C=
Gas
15 mm diameter
H=
810mm
Z=
Flue gas outlet
80 mm diameter
F=
Condensate
32 mm dia (after trap 25 mm dia flexible)
Y=
Air supply inlet
80
mm diameter

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4.3 Unpacking the appliance
1. Unpack the appliance.
2. Check the content of the packaging. This consists of:-
• Appliance (A)
• Mounting strip (B)
• Condensate trap (C)
• Installation Instructions
• User Operating Instructions
• Warranty card
3. Valve set (supplied separately with boiler) comprising 2 x 22mm
isolation valves 1 x gas valve.
4. Check the appliance for any damage: report damage to the Supplier
immediately.
CAUTION: This appliance should be lifted and handled by 2 people.
(Weight: 39 kg)
4.4 Additional dimensions
The diagram shown below gives additional dimensions primarily for the
mounting arrangement using the OPTIONAL mounting bracket.
Note: The centre line of the hexagonal notch in the mounting bracket is also the
centre line of the flue hole.

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4.5 Boiler location
Keep 50 mm free space above the front panel in order to be able to
remove the front panel from the casing. Allow 140 mm on the left side for
swinging out the expansion vessel during commissioning/service.
The appliance can be fitted to a mounting frame. The assembly or just
the appliance should be mounted to a wall with sufficient bearing
strength. In case of light wall constructions resonance sounds may
occur.
The appliance is suitable for mounting on a combustible wall (eg stud
wall).
There must be an earthed electrical supply within a distance of 1 m from
the appliance.
In order to avoid freezing of the condensate discharge the appliance
should be installed in a frost-free room.
4.5.1 Installation in a kitchen cupboard
Make sure there is sufficient ventilation above and below the appliance.
When the appliance is placed in a small cupboard ventilation openings
of at least 50 cm
2
must be made.
4.5.2 Installation in an airing cupboard
Compartment ventilation is not required for a standard airing cupboard
(eg 0.6 x 0.6 x 2.3m high).
4.5.3 Remove front panel
Remove the optional pipework cover and the front panel for carrying out
work on the appliance as follows:-
1. Remove the pipework cover (A) if used forwards.
2. Unscrew both recessed crosshead screws (B) at the bottom of the
appliance.
3. Lift the front panel (C) vertically upwards and remove it forwards.
Clearances
Above casing 200mm min
Below casing 230mm min (HE26)
340mm min (HE40C)
RH 30mm min
LH 30mm min (in operation)
LH 140mm min (servicing HE26)
Front 30mm min (in operation)
Front 450mm min (servicing)

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4.6 Mounting
Depending on the mounting option ordered the following mounting
methods are available:-
Mounting strip (A) alone
OR mounting strip (A) and optional pipe mounting bracket (B)
OR rear mounting frame (C) and pipe mounting bracket (B) which are
both optional items. This arrangement allows for vertical pipework behind
the boiler.
Note that when the pipe mounting bracket is used, the pipes can be
connected before installing the appliance.
4.6.1 Fitting the mounting strip
1. Fasten the mounting strip horizontally to the wall using the screws
and plugs supplied.
2. Mount the appliance.
4.6.2 Fitting the mounting strip and the mounting bracket
1. Fasten the mounting strip and the pipe mounting bracket
horizontally to the wall according to the drilling pattern using the
screws and plugs supplied.
4.6.3 Fitting the rear mounting frame
1. Fasten the frame vertically to the wall using screws and plugs.
2. Fasten the optional pipe mounting bracket to the frame using the
fixings supplied.
Caution
The appliance is wider than the frame by 20mm.
A
C
B
A
B

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4.6.4 Installation connections
1. Make the various connections to the valves (see diagram).
2. Ensure a filling loop (between a domestic water pipe and the CH
system) is installed for filling the central heating system.
3. For most installations the flexible tube for the safety discharge will
be long enough to fit into the condensate discharge waste pipe (see
below). In cases where this does not apply install a 15 mm copper
safety discharge pipe to fit into the waste pipe (as shown in the
diagram §5.1) or run separately to a safe discharge position on the
outside wall of the building.
4.7 Mount the appliance
1. Check whether the compression rings of the optional mounting
bracket are straight in the connectors.
2. Place the appliance: slide it top-down over the mounting strip. Make
sure that the pipes simultaneously slide into the compression
fittings of the optional mounting bracket.
3. The flexible tube from the condensate trap should be inserted into
an open waste pipe of not less than 32 mm diameter. If connected
to a soil pipe or waste system the waste pipe must include a trap
(similar to arrangement for washing machine). For more information
on condensate disposal please refer to §4.9.
4. The flexible tube from the pressure relief safety valve should be
inserted into the waste pipe or pushed over the 15 mm copper
discharge pipe if provided.
5. Tighten the compression fittings to the optional mounting bracket.
6. Mount the air supply and the flue discharge.
7. Close the air supply opening that is not used with the plug supplied.
4.8 Fit the pipe work cover (option only for H 26)
1. Insert the four hooks of the pipe work cover in the slots of the
appliance.
2. Slide the cover backwards sliding the hooks into the slots and
locking the cover.

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4.9 Condensate disposal
The appliance is provided with a 25 mm flexible pipe from its
condensate trap. As given in §4.7 this should be inserted into an open
waste pipe of not less than 32 mm diameter together with the safety
discharge pipe. The condensate is slightly acidic (pH between 3 and
6) and should be disposed of in the following ways using suitable
plastic waste pipe (Note: copper or steel must not be used):-
• internal stack pipe (see diagram)
• waste pipe (see diagrams)
• external drain or gulley
• purpose made soak-away
The pipe work must incorporate a minimum fall of 2.5 degrees (or
44mm/metre) towards its point of termination. Condensate pipe work
external to the property or in an unheated space (eg a garage) must
be protected against freezing through the use of pipe insulation and
trace heating. Atmos can supply trace heating.
If an external drain or gulley is used then the open end of the pipe
should be terminated below the grid level but above the water level.
If a proprietary soak-away is used install at least 1 metre away from
the external wall and clear of foundations and services. The soak-
away is buried in the ground and surrounded by limestone chippings
to neutralise the condensate.

20
5. CONN CTIONS
5.1 Connect the CH system
1. Flush the CH system thoroughly.
2. Connect the flow and return pipes using the 22mm isolation valves.
All pipes must be mounted tension-free in order to avoid ticking of
the pipes.
Existing connections must not be twisted in order to avoid leaks at
the connections with the external pipes.
The CH system should be provided with:-
• A filling loop in the return pipe directly below the appliance.
• A drain tap at the lowest point of the system.
• An expansion tank. The HE26 comes complete with 6 litre
expansion tank. It may be necessary to fit an additional
expansion tank.
5.1.1 xpansion vessel
The HE26 appliance is fitted with a 6 litre expansion vessel which is
adequate for a system with a water volume not exceeding 100 litres
typically 8 radiators. For larger volume systems an additional expansion
vessel must be fitted. Atmos can supply a 12 litre or 18 litre Robokit.
The HE40C appliance is not fitted with an expansion vessel.
5.1.2 Thermostatic radiator valves
Building regulations require a room thermostat to be fitted on all
installations. Do not fit a thermostatic valve on the radiators in the room
where the thermostat is situated otherwise the controls will not function
correctly.
5.1.3 System bypass
A by-pass is not required for safe operation of the boiler. For heating
systems where there are thermostatic valves on all radiators or where
there are other system flow restrictions such as zone valves a by-pass
should be fitted to reduce system noise and to protect the pump. The by-
pass should comprise a proprietary by-pass valve with adjustable flow
regulation not a fixed setting valve. Atmos can supply this valve.
Note
The flexible tube from the pressure relief safety
valve can be inserted directly into the waste pipe if
suitably located. The flexible tube must be installed
so that there are no sharp bends that kink the pipe
and cause a restriction in the flow.