Radiant RKA 25 User manual

SEDBUK BAND A
GAS COUNCIL NUMBER: 47-651-21
Installation, operating, commissioning and maintenance instructions.
CE 0694 TG05A095.A0306
Documentazione Tecnica RADIANT BRUCIATORI S.p.A. Montelabbate (PU) ITALY ENGLISH
Instruction Manual
for models
RKA 25
Premix condensing boiler
with storage cylinder

CONTENTS
1. General information
1.1 General Installation Information page 1
1.2 Product conformity page 3
2. Technical characteristics
2.1 Technical data page 4
2.2 Dimensions page 5
2.3 Internal parts of the boiler page 6
2.4 Water circuit page 7
2.5 Circulation pump head graph page 8
2.6 Printed circuit board page 9
2.7 Control panel page 10
3. Installing the appliance (authorised personnel)
3.1 Reference standard page 11
3.2 Unpacking page 12
3.3 Installing the boiler page 13
3.4 Water connections page 14
3.5 Central heating circuit page 15
3.6 Condensate drain page 16
3.7 Discharge piping page 17
3.8 D.H.W circulating loop page 18
3.9 Gas connection page 19
3.10 Electrical connections page 19
3.11 Room thermostat - outdoor sensor connections page 20
3.12 Remote control connection page 21
3.13 Flue connections page 24
4. Initial start up (authorised personnel)
4.1 General warnings (flushing the system) page 30
4.2 Filling the system page 31
4.3 Flushing the system page 32
4.4 Filling the condensate trap page 32
4.5 Starting up the boiler page 33

CONTENTS
5. Commissioning the appliance (authorised personnel)
5.1 Parameter table page 34
5.2 Parameter programming - regulating the gas pressure page 35
5.3 Gas data page 40
5.4 Regulating the stepped ignition sequence page 41
5.5 Converting the boiler to a different gas type page 42
6. Servicing the appliance (authorised personnel)
6.1 General warnings page 43
6.2 Boiler inspection page 43
6.3 Maintenance for unvented components page 44
6.4 Accessing the boiler page 45
6.5 Draining the central heating and domestic hot water system page 46
6.6 Wiring diagrams page 47
6.7 Troubleshooting page 48
6.8 Diagnostics page 49
6.9 Parts list page 50

GENERAL INFORMATION
TG05A095.A0306 1
1. GENERAL INSTRUCTIONS
1.1 General warnings
Professionally qualified personnel in accordance with current laws and standards and in line with
the manufacturer’s instructions must install the appliance. To check for authorised qualified
engineers please contact CORGI 01256-372400
The term professionally qualified personnel refers to persons possessing the appropriate technical
competencies within the sector with regard to the installation and servicing of domestic and
industrial central heating plants and domestic hot water production systems as provided for by
current standards.
The commissioning of the boiler and any subsequent works carried out on the appliance must be
effected by an appropriately qualified technician or an approved Radiant Helpline Service Centre.
The appliance must be used solely for the purpose for which it has been designed and
manufactured: central heating and domestic hot water production. Any other use is deemed as
improper and as such dangerous. Under no circumstances will the manufacturer be held
responsible for damage or injury to persons or animals caused by errors in the installation and/or
use of the appliance, or through non-compliance with current local and national standards and/or
the manufacturer’s instructions.
The installation, operation and maintenance manual forms an integral and essential part of the
product and must be kept near the appliance always.
This Manufacturer Installation and Maintenance manual must not be removed on completion of the
installation; must be kept in a safe place and made available for future reference. This Manual must
be left along with the Benchmark commissioning booklet with the boiler as Regulation 29 of the
HSC Gas safety (installation and use) Regulations 1998.
The warnings contained in this chapter have been written for the appliance user, the installer and
the service engineer.
The “operating instructions” chapter of this manual must be read carefully as it provides
information on the operation and the operating limits of the appliance.
This appliance must be used exclusively in an un-vented central heating system.
•After the removal of all the packaging, check that the appliance has not been damaged. In case of doubt, do not
attempt to use the product but refer to the supplier. Packing materials (cardboard box, wooden crate, nails,
staples, plastic bags, polystyrene, etc.) must not be left within reach of children in that these items represent a
potential hazard and must be disposed of in a responsible manner.
•Before carrying out any cleaning or maintenance operations, disconnect the appliance from the mains electricity
supply by switching off at the main switch and/or any other isolating device.
•Do not obstruct the air intake or heat dissipation grills.
•Do not obstruct the openings of the air intake or flue ducts.
•In the case of a fault and/or malfunction in the appliance, shut down the system. Do not interfere with or attempt
any repairs. Call for professionally qualified technical assistance only. Radiant Helpline UK 0870 770 0414
•Any warranty repairs to the appliance must be carried out exclusively by the manufacturer’s authorised service
centre using original spare parts. Non-compliance with the above requirements may compromise the safety of
the appliance and invalidate the warranty. In order to guarantee the efficiency of the appliance and its correct
operation, it must be serviced regularly by professionally qualified personnel in line with the manufacturer’s
instructions.
•When the appliance is no longer required for use, any parts that may constitute potential sources of danger
must be rendered harmless.
•Only original accessories or optional extras (including electrical parts) must be used with the appliance.

GENERAL INFORMATION
TG05A095.A0306 2
•Should there be a smell of gas present in the room where the appliance is installed, DO NOT attempt to activate
any electric switches, telephones or any other equipment that may cause sparks. Open doors and windows
immediately to create a current of air and ventilate the room. Shut-off the main gas supply valve (at the meter),
or on the cylinder in the case of bottled gas, and call an authorised service centre.
•Do not attempt to interfere with the appliance in any way.
•Central heating systems fitted with radiator thermostats must be fitted with an external automatic bypass.
•As dictated by current legislation, this appliance must be installed exclusively by qualified personnel in
accordance with standards UNI-CIG 7129 and 7131, and any amendments or updates, and in line with the
requirements of the local fire service and gas supplier. Before starting the boiler for the first time, make sure that
it is connected to a water supply and central heating system compatible with its performance characteristics.
The room must be ventilated by means of an air intake (refer to UNI 7129/92 and UNI 7129/95 FA).
•Check the technical data reported on the packing and on the rating plate located on the inside of the front
casing. Also check that the burner is appropriate for the type of gas to burn.
•Make sure that the pipes and fittings used for the gas service are perfectly tight and that there are no
gas leaks.
•Prior to start-up, the central heating pipes should be flushed to remove any residues that could compromise the
operation of the appliance.
•The appliance can be regarded as being electrically safe when it has been connected to an efficient earth
system installed in accordance with the requirements of current safety standards (Standard CEI 64-8 Electrical
Installations).
•This fundamental safety requirement must be checked and verified. In case of doubt, have the electrical system
checked by a qualified electrician. The manufacturer will not be held liable for any damage or injury caused as a
result of an ineffective or non-existent earth system.
•The domestic power supply must be checked by a qualified electrician to ensure that it can support the
maximum power absorption of the appliance, as indicated on the rating plate. In particular, make sure that the
cable ratings are adequate for the power absorbed.
•Do not use adapters; multiple sockets or extension leads to connect the appliance to the mains power supply.
•The appliance must be connected to the mains power supply through an appropriate electrical isolator in
accordance with the current wiring regulations.
•When using an electrical appliance, a few fundamental rules must be observed:
•Do not touch the appliance with damp or wet parts of the body or when barefoot
•Do not pull on the electric wires
•Do not leave the appliance exposed to atmospheric elements (rain, sun, etc,) unless these conditions have
been expressly provided for.
•Do not allow the appliance to be used by children or anyone unfamiliar with its operation.
•The user must not replace the power supply cable.
•If the cable is damaged in any way, switch off the appliance and have the cable replaced by a suitably qualified
electrician.
•Radiant Helpline UK 0870 770 0414

GENERAL INFORMATION
TG05A095.A0306 3
1.2 Product conformity
RADIANT BRUCIATORI S.p.A. declare that all its products are manufactured to a high specification and in compliance with the
relevant standards.
All RADIANT boilers are CE certified and possess technical and functional characteristics that comply with the following
standards:
UNI-CIG 7271 (April 1988)
UNI-CIG 9893 (December 1991)
UNI EN 297 for GAS-FIRED CENTRAL HEATING BOILERS TYPE B OF NOMINAL HEAT INPUT ≤70 kW
EN 483 for GAS-FIRED CENTRAL HEATING BOILERS TYPE C OF NOMINAL HEAT INPUT ≤70 kW
UNI EN 677 for GAS-FIRED CENTRAL HEATING BOILERS. SPECIFIC REQUIREMENTS FOR CONDENSING BOILERS
WITH NOMINAL HEAT INPUT ≤70 kW
The gas-fired boilers also comply with the following directives:
GAS APPLIANCES DIRECTIVE 90/396 CEE for CE compliance
LOW VOLTAGE DIRECTIVE 73/23 CEE
ELECTROMAGNETIC COMPATIBILITY DIRECTIVE 89/336 CEE
BOILER EFFICIENCY DIRECTIVE 92/42 CEE
The materials used such as copper, brass, stainless steel, etc. form a compact, homogeneous, highly functional unit that is easy
to install and simple to operate. In its simplicity, the wall-mounted appliance is equipped with all the appropriate accessories
required to make it a fully independent boiler capable of satisfying domestic hot water production and central heating needs. All
boilers are fully inspected and are accompanied by a quality certificate, signed by the inspector, and a guarantee certificate. This
manual must be kept in a safe place and must accompany the boiler at all times.
RADIANT BRUCIATORI S.p.A. will not be held responsible for any misinterpretation of this manual resulting from the
inaccurate translation of same.
RADIANT BRUCIATORI S.p.A. will not be held responsible for the consequences in the case of non-observance of the
instructions contained in this manual or in the case where actions not specifically described herein are undertaken.

TECHNICAL CHARACTERISTICS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 4
2. TECHNICAL CHARACTERISTICS
2.1 Technical data
Appliance Model RKA 25
Technical Data
CE certification no. n° 0694BN3485
Flue category (UNI10642) C13, C33, C43, C53, C83
Heat Input max kW 25
Heat Input min kW 9
Heat Output max (80/60°) kW 24.60
Heat Output max (50/30°) % 26.68
Heat Output min (80/60°) % 8.73
Efficiency 100% load (80/60°) kW 98,40
Efficiency 100% load (50/30°) kW 106,70
Efficiency 30% load (80/60°) % 100.10
Efficiency 30% load (50/30°) % 106,30
Gas Directive 92/42/ECC - Efficiency marking stars 4
NOx class (European Standard UNI EN 297 – pr A5 class 5
Sedbuk band A
Heating circuit
Central heating water temperature setting (min-max) °C 30-80
Max. Heating temperature °C 80
Max. Working pressure (heating) Bar 2.5
Min. working pressure (heating) Bar 0.3
Expansion vessel capacity Litres 10
Domestic hot water
D.H.W. temperature setting °C 35-60
Max. Hot water working pressure bar 6
Min. Hot water working pressure bar 0.5
Continuous hot water supply - ∆t 30° - mixed water litres/h 726
Max. continuous hot water supply - ∆t 30° mixed water - first 10 minutes litres 141
Storage cylinder capacity litri 20
Dimensions
Width mm 490
Height mm 900
Depth mm 450
Weight kg 70
Hydraulic connections
Flow connection Ø 3/4”
Return connection Ø 3/4”
Cold water connection Ø 1/2”
Hot water connection Ø 1/2”
Gas connection Ø 1/2”
Flue systems
Horizontal-Coaxial flue system - kit K Ø 100/60
Max. flue length m 5
Twin pipe flue system - kit H Ø 80/80
Max. flue length m 50
Vertical-Coaxial flue system - kit V Ø 100/60
Max. flue length m 5
Gas Supply
Natural Gas G 20
Inlet pressure mbar 20
Gas consumption m3/h 2.83
Liquid Butane Gas G 30
Max. Inlet pressure mbar 30
Gas consumption kg/h 2.11
Liquid Propane Gas G 31
Max. Inlet pressure mbar 37
Gas consumption kg/h 2.08
Electrical supply
Power supply V/Hz 230/50
Maximum Power consumption W 180
Electrical protection IP IPX4D

TECHNICAL CHARACTERISTICS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 5
2.2 Dimensions
mod. RKA 25
HR HEATING RETURN CONNECTION Ø3/4”
HF HEATING FLOW CONNECTION Ø3/4”
G GAS CONNECTION Ø1/2”
CWI COLD WATER CONNECTION Ø1/2”
HWO HOT WATER CONNECTION Ø1/2”
SC CONDENSATE DRAIN -
450
53
95164
225
450
84.5 78 8070 102 75.5
HR
11 715
GCWI HFHWO
900
106.5
155
65 160 200 65
277 106.5
490
301
490

TECHNICAL CHARACTERISTICS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 6
2.3 Internal parts of the boiler
mod. RKA 25
LEGEND
1. HEATING SENSOR
2. CONDENSING EXCHANGER
3. HEATING SAFETY THERMOSTAT
4. IGNITION ELECTRODE
5. FRAME
6. FLAME IONISATION ELECTRODE
7. FAN
8. MIXING GROUP
9. ELECTRONIC IGNITION BOARD
10. ELECTRONIC GAS VALVE VK4105 A 1001
11. AUTOMATIC AIR VENT
12. 3-SPEED CIRCULATION PUMP WITH AIR VENT
13. WATER PRESSURE SWITCH
14. HEATING CIRCUIT 3 bar PRESSURE RELIEF VALVE
15. DRAINING TAP
16. FLOW LIMITER
17. BY-PASS
18. AIR COMBUSTION INTAKE PIPE
19. WATER TRAP SIPHON
20. ELECTRONIC FLOWSWITCH
21. FLAT PLATE TYPE EXCHANGER
22. 3-WAY DIVERTER VALVE
23. WATER PRESSURE GAUGE
24. HOT WATER SENSOR
25. BOILER DRAING TAP
26. ANODE
27. 25 LITRE WATER STORAGE TANK
28. 7 ATE PRESSURE RELIEF VALVE (HOT WATER)
6
9
16
6
28
26
23
25
19
20
21
22
24
13
14
12
11
8
7
10
18
27
4
1
3
5
2
11
17

TECHNICAL CHARACTERISTICS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 7
2.4 Water circuit
LEGEND
1. PRIMARY CONDENSING HEAT
EXCHANGER
2. PREMIX BURNER UNIT (GAS MANIFOLD +
BURNER)
3. CONDENSATE DRAIN PIPE
4. IGNITION ELECTRODE
5. SENSOR ELECTRODE
6. ELECTRIC FAN
7. VENTURI
8. ELECTRONIC IGNITION PCB
9. ELECTRONIC GAS VALVE
10. HEATING CIRCUIT 3 BAR SAFETY VALVE
11. AUTOMATIC AIR VENT
12. HEATING SAFETY THERMOSTAT
13. HEATING SENSOR
14. CIRCULATION PUMP WITH AIR VENT
15. WATER PRESSURE SWITCH
16. FLUE DUCT CONNECTION CHAMBER
17. EXHAUST TEST SOCKET
18. EXPANSION TANK
19. AIR INTAKE DUCT
20. CONDENSATE TRAP
21. PRESSURE GAUGE
22. BYPASS
23. CONDENSATE TRAP OVERFLOW
24. SYSTEM DRAIN VALVE
25. SEALED CHAMBER CASING
26. FLOW LIMITER
27. ELECTRONIC FLOW SWITCH
28. D.H.W HEAT EXCHANGER
29. 3-WAY DIVERTER VALVE
30. D.H.W. SENSOR
31. HOT WATER SENSOR
32. 7 ATE PRESSURE RELIEF VALVE (HOT
WATER)
33. 25 LITRE WATER STORAGE TANK
34. ANODE
35. NO RETURN VALVE
LEGEND
HR HEATING RETURN CWI COLD WATER INLET CONNECTION
HF HEATING FLOW HWO HOT WATER OUTLET
GGAS SC CONDENSATE DRAIN
G
HWO HFHR CWI SC
11
17
13
12
5
4
18
1
2
6
9
11
14
15
10
24
27
23
20
29
28
19
25
3
7
32
34
33
31
35

TECHNICAL CHARACTERISTICS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 8
2.5 Circulation pump head/flow graph
Head available for the system with bypass 50% open
Head available for the system at maximum speed
III
14001200 1600
70
50
60
40
1000
800400 600
30
10
20
0
0
Head (kPa)
Flow l/h
200
III
Appliance Loss

TECHNICAL CHARACTERISTICS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 9
2.6 DIAGNOCODE®series SM 20015 Printed Circuit Board
Technical characteristics Part Number 76655LA
M5
M3
M6
M7
M11
M13
M4
M2 M1
M12
M10
M8
M9
The new circuit boards greatly simplify the adjustment of the operating parameters of the entire system. In fact, it is
now possible to adjust the following settings:
Adjustments possible by service personnel only
•Standard / reduced temperature 30/80 – 25/40
•Water hammer prevention function
•Heating timer adjustable from 0 to 7.5 minutes standby Anti cycling device
•Central heating Pump overrun
•D.H.W Pump overrun
•Minimum gas pressure
•Maximum heating Load
User settings
•On/Off
•Heating temperature 30-80 °C – 25-40°C (reduced)
•D.H.W temperature 35-60 °C
•Summer/winter/heating only
•Lock-out
•Normal water pressure
•Water deficiency indicator
•Temperature display

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 10
2.7 Control panel
LEGEND
1. ON/OFF SWITCH
2. HEATING TEMPERATURE CONTROL KNOB
3. D.H.W TEMPERATURE CONTROL KNOB (only for model RKR 25).
4. OUTSIDE TEMPERATURE DISPLAY BUTTON (ONLY WITH OPTIONAL OUTDOOR SENSOR FITTED)
5. SERVICE BUTTON.
6. SUMMER, WINTER OR SUMMER/WINTER SELECTION BUTTON.
7. TERMINAL BOARD FOR EXTERNAL WIRING.
8. D.H.W FUNCTION INDICATOR (THE BOILER IS IN SUMMER OR SUMMER/WINTER MODE ) (only for model RKR 25)
FIXED LIGHT – Hot water mode is selected
FLASHING LIGHT - THERE IS A CURRENT DEMAND FOR HOT WATER
9. CENTRAL HEATING FUNCTION INDICATOR (THE BOILER IS IN WINTER OR SUMMER/WINTER MODE )
FIXED LIGHT – Heating mode has been selected
FLASHING LIGHT - There is a current demand for heating
10. ERROR WARNING LIGHT. THE APPROPRIATE ERROR CODE FLASHES ON THE DISPLAY (13)
11. LED INDICATING SYSTEM WATER PRESSURE AT 1.5 BAR
12. LED INDICATING INSUFFICIENT WATER IN THE SYSTEM
13. TEMPERATURE AND ERROR CODE DISPLAY
ERROR CODES:
1. IONISATION LOCKOUT
2. SAFETY THERMOSTAT TRIPPED
3. EXHAUST THERMOSTAT TRIPPED ( NOT-APPLICABLE)
4. LOW WATER PRESSURE ALARM
5. HEATING SENSOR MALFUNCTION
6. D.H.W SENSOR MALFUNCTION (ONLY FOR MODEL RKR 25)
12. BOILER D.H.W SENSOR MALFUNCTION ( NOT-APPLICABLE)
14. AIR PRESSURE SWITCH MALFUNCTION ( NOT-APPLICABLE)
22. PARAMETER PROGRAMMING RESET REQUEST
12 345
S
76
11 10
8
9
1213

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 11
3. INSTALLING THE APPLIANCE
3.1 Reference standard
The following list is the full lists of codes of practice and British Standards That engineers should work to in the UK.
It is law in the UK that a competent person installs all gas-burning appliances. Please ensure that the installer is a
class of person approved for the time being by the Heath and Safety Executive for the purpose of carrying out this
work. An approved engineer should be registered to an approved scheme i.e. CORGI 01256-372400.
All works should be carried out in accordance with the following,
Health & Safety at Work Act 1974
Gas Safety & Use Regulations 1998
All relevant Building Regulations as detailed by the office of the Deputy
Prime Minister, Parts A-structure, B-safety in fire, F-ventilation, G3-Hot water storage,
J-Heat producing Appliances, L- Fuel conservation (amended)
Building Standards Scotland
The Water Supply Regulations 1999
The Water Bylaws Scotland 2000
The Electricity at work regulations 1999
The installations should be carried out in accordance with the following British Standards Codes of Practice
BS 5440:Part1 2000 – Flues
BS 5440:Part2 2000 – Air Supply
BS 6700: 1987 – Specification for installation of cold water supplies for domestic purposes (1st, 2nd and 3rd family
gases)
BS 5449: 1990 Forced circulation hot water systems
BS 5446: 2000 Specification for installation of hot water supplies for domestic purposes (1st, 2nd and 3rd family
gases)
BS6798: 2000 Specification for installation of gas-fired boilers of rated input not exceeding 70 kW net
BS6891: Specification for installation of low pressure gas pipe work of up to 28 mm (R1) in domestic premises (2nd
family gas)
BS7593: 1992 Code of practice for treatment of water in domestic hot water central heating systems
BS7671: 2001 IEE wiring regulations.
This appliance meets the requirements of IPX4D rating for electrical appliances.
Failure to install a gas appliance correctly and in accordance with the above norms could lead to prosecution. It is
in the interest of the installer and safety that the law is complied with.
The manufacturers instructions form an integral part of the installation and should be left with the appliance but do
not over ride in anyway statutory obligations.

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 12
B
C
A
3.2 Unpacking
■The materials (cardboard) used for packing the appliance are fully recyclable.
■It is recommended that the packing material is only removed prior to installing the boiler. The
manufacturer will not be held responsible for damage caused by incorrect storage of the product.
■Packing materials (plastic bags, polystyrene, nails, etc.) must not be left within reach of children, in that
these items represent a potential hazard.
A. Place the packed
appliance on the floor (fig.
1) making sure that the
"up” arrow is facing down.
Remove the staples and
open out the four flaps of
the box.
B. Rotate the boiler
90° while manually
supporting it from
underneath
C. Lift the box and
remove the protections.
Lift the boiler by grasping
the rear part and proceed
with the installation.
STORAGE & HANDLING
Please note that prior to installation the Radiant boilers should be stored in the horizontal position with no more
than three boilers to a stack;
Ensure that the boilers are stored in dry conditions and be aware that the carton is a tow-man lift;
Please check that this boiler has been supplied with an unvented inlet kit and flue system
Fig. 1

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 13
MINIMUM DISTANCES IN mm
H
A
XLY
Model
RKA 25
XYL H
10004906060
B
AB
200 300
3.3 Installing the boiler
■The appliance must be installed
exclusively on a flat vertical wall
capable of supporting its weight.
■When mounting the boiler on the
wall, make absolutely sure that the
boiler is fitted perfectly level. If the
boiler is not level, the condensate
will not flow correctly through the
drainpipe but will instead
accumulate inside the main
exchanger and stop it from
working.
In order to allow access to the interior of
the boiler for maintenance purposes, it is
important that the minimum distances
indicated in figure 1 are respected. To
make the installation easier, the boiler is
supplied with a template to enable the
pipe connections to be positioned prior
to fixing the appliance to the wall.
To install the boiler, proceed as follows
(see fig. 2):
a. Use a spirit level (of not less than 25
mm long) to mark a horizontal line on
the wall where the boiler is to be
fitted.
b. Position the top of the template along
the line drawn with the level,
respecting the distances indicated.
Then mark the centres of the
positions of the two wall-plugs or
anchors. Finally, mark the positions of
the water and gas pipes.
c. Remove the template and install the
domestic hot and cold water pipes,
the gas supply pipe and the central
heating pipes using the fittings
supplied with the boiler.
d. Please ensure that connections made
to the storage cylinder pressure and
temperature relief valve is solely used
for this purpose and not shared with
any other discharge or inlet pipe.
e. Fix the boiler to the wall using the
wall plugs or bracket and connect the
pipes.
Fig. 2
Fig. 1

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 14
HR
HWO
CWI
G
HF
HR HWO GCWI HF
75.510270 807884.5
3.4 Water connections
In order to safeguard the heat
exchanger and circulation pump, it is
recommended that the system is hot-
flushed to remove any impurities
(especially oil and grease) from the
pipes and radiators.
Please ensure that all discharge and
safety pipes are connected and
terminated in line with page 17 of this
manual
Make sure that the domestic water and
central heating pipes are not used to
earth the electrical system. The pipes
are totally unsuitable for this purpose.
Isolating Valves must be installed on
the heating and D.H.W circuits. This will
facilitate all maintenance and service
operations where the boiler needs to be
drained.
■To prevent vibration and noise coming from
the system, do not use pipes of reduced
diameter, short radius elbows or severe
reductions in the cross sections of the water
passages.
■The increase in temperature of the hot water
storage units causes a consequent increase
in volume of the water contained in them. In
order to compensate for this increase in
volume, the appliance is fitted with an
expansion vessel specifically for the
domestic hot water system.
In order to guarantee the reliability of the
boiler and prevent permanent damage in
areas with high water inlet pressure too, a
3.5 bar pressure reducing valve should be
fitted.
■In order to prevent scaling and eventual
damage to the D.H.W heat exchanger, the
mains water supply must not have a
hardness rating of more than 25 °F. It is
nevertheless advisable to check the
properties of the water supply and install the
appropriate treatment devices where
necessary.
The cold water supply pressure at the inlet to the boiler should be between 0.5 and 3.5bar
The frequency of the heat exchanger coil cleaning depends on the hardness of the mains water supply and the
presence of residual solids or impurities, which are often present in the case of a new installation. If the
characteristics of the mains water supply are such that require it to be treated, then the appropriate treatment
devices must be installed, while in the case of residues, an in-line filter should be sufficient.
Fig. 2
Fig. 1

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 15
3.5 Central heating circuit
The boiler is designed for use in a sealed central heating system in accordance with the requirements of BS 5449 and BS 6798.
The system should be designed to operate with flow temperatures of up to 82°C. When designing the system, the pump head,
expansion vessel size, mean radiator temperature, etc. must all be taken into account. Refer to the pump performance table for
guidelines.
System volume -The expansion vessel incorporated into the boiler is suitable for a sealed heating system
The boiler is supplied with the following components built in:-
Pressure relief valve -complying with BS 6759 and set to operate at 3 bars. The outlet connection of the boiler safety valve
must terminate to atmosphere in accordance with current regulations. The manufacturer will not be held responsible for
flooding caused by the operation of the safety valve in the case of system overpressure..
Pressure gauge -To indicates the system pressure to be maintained.
Expansion vessel. Conforming to BS 4814 with a capacity of 10 litres.
By-pass -The boiler incorporates a by-pass, however where all radiators are fitted with thermostatic radiator valves it is
recommended an automatic system by-pass is fitted.
Additional expansion
vessel (if required)
Double check valve assy
Temperature/pressure
relief valve
Boiler
Automatic air vent
Heating flow
Heating return
System
drain tap
Note: A drain tap should be installed at the lowest point of the
heatin
g
circuit and beneath the a
pp
liance
Note: If required, an automatic
by-pass is preferred
Radiator
valve
Filling point
DHW outlet
Pressure reducing
valve (supplied)
Mains water
inlet
Static head of system
Make up vessel
Heating by-pass
(if required)
Lockshield valve
Filling the central heating system - figs. 2-3
The system design pressure (cold) should be set to 1.5 bar. This pressure is equivalent to a static head of 15.4 metres of
water.
Provision should be made to replace water lost from the system. This can be by manual or automatic means. as shown in Figs.
2 and 3. The position for connecting an automatic make-up vessel is indicated in Fig. 1. A double check valve assembly must
be used. as shown in Fig. 3.
Filling of the system must be carried out in a manner approved by the local Water Undertaking. Where allowed the system may
be filled via a temporary connection as shown in Fig. 2. After filling, always disconnect the flexible hose of the filling loop.
All fittings used in the system must be able to withstand pressures up to 3 bar.
Drain taps (to BS 2879) must be used to allow the system to be completely drained.
Double
check valve
assembly
Test
cock
Feed cistern to be
located above highest
point in the system
Overflow
Heating
circuit
return
Test
cock
Double
check valve
assembly
Stop
valve
M
a
i
ns water
supply
Mains
water
supply
Stop
valve
Filling loop
temporarily
connected
Hose
unions
Heating
circuit
return
In order to prevent scaling or deposits in the primary heat exchanger, the mains supply water to the heating circuit
must be treated according to the requirements of standard.
This treatment is indispensable in the case where the circuit is frequently topped-up or when the system is often either partially
or fully drained.
Fig. 1
Fig. 2 Fig. 3

INSTALLATION INSTRUCTIONS
CONDENSING BOILOES WITH STORAGE - TG05A095.A0306 16
3.6 Condensate drain
FAILURE TO INSTALL THE CONDENSATE
DISCHARGE PIPEWORK CORRECTLY WILL
AFFECT THE RELIABLE OPERATION OF THE
BOILER The condensate discharge pipe MUST NOT
RISE at any point along its length. There MUST be a
fall of AT LEAST 2.5° (50mm per metre) along the
entire run.
I. The condensate outlet terminates in 22 mm nut and
seal for the connection of 22 mm (3/4 in) plastic
overflow pipe which should generally discharge
internally into the household drainage system. If this is
not possible, discharge into an outside drain is
acceptable.
2. Ensure the discharge of condensate complies with
any national or local regulations in force.
BS 6798:2000 & Part H I of the Building Regulations
give further guidance.
3. The discharge pipe should be run in a proprietary
drain pipe material e.g. PVC, PVC-U, ABS, PVC-C or
PP.
4. Metal pipe work is NOT suitable for use in
condensate discharge systems.
5. The pipe should be a minimum of 21.5 mm diameter
and must be supported using suitably spaced clips to
prevent sagging.
6. Any pipe fitted externally must not exceed 3 metres.
7 Any condensate discharge pipe work external to the
building (or in an unheated part of it e.g. garage) must
be insulated to protect against frost. It is also
recommended that the pipe diameter is increased to
32mm.
8. If the boiler is fitted in an unheated location the entire
condensate discharge pipe should be treated as an
external run.
9. In alI cases discharge pipe must be installed to aid
disposal of the condensate. T o reduce the risk of
condensate being trapped, as few bends and fittings as
possible should be used.
10. When discharging condensate into a soil stack or
waste pipe the effects of existing plumbing must be
considered. If soil pipes or waste pipes are subjected
to internal pressure fluctuations when WC's are flushed
or sinks emptied then back-pressure may force water
out of the boiler trap and cause appliance lockout.
Examples are shown of the following methods of
termination:-
i) to an internal soil & vent pipe
ii) via an internal discharge branch (e.g. sink waste)
iii) to a drain or gully
iv) to a purpose made soak away
450mm min
Holes in the soak-away must
face away from the building
500mm min
External termination to a purpose made soak-away
External termination to a drain or gully
Pipe must terminate above
water level but below
surrounding surface
50mmpermetreofpiperun
2.5°Minimumfall
50mmpermetreofpiperun
2.5°Minimumfall
Boiler
Pipe must terminate above
water level but below
surrounding surface
50mmpermetreofpiperun
2.5°Minimumfall
External termination via internal discharge
branch e.g. sink waste - downstream
Sink
2.5°Minimumfall
50mmpermetreofpiperun
Termination to an internal soil and vent pipe
Boiler
Boiler
Boiler