MHS Boilers STRATA1 Series User guide

STRATA1
38 & 38/46 COMBI
WALL MOUNTED, GAS FIRED,
ULTRA HIGH EFFICIENCY CONDENSING BOILERS
INSTRUCTIONS FOR INSTALLATION,
SERVICING & OPERATION OF
THE MODEL 38 BOILER & THE 38/46 COMBI
L 101

2
STRATA1
38 & 38/46 COMBI
Index
page section
3
. . . . . . . . . . . 1.0 General Notes
4 . . . . . . . . . . . 2.0 Product Description
5 . . . . . . . . . . . 2.0 Product Description (contd)
6 . . . . . . . . . . . 3.0 Technical Data & Dimensions
7 . . . . . . . . . . . 4.0 Delivery Consignment/Unpacking The Boiler
. . . . . . . . . . . . 5.0 Boiler Location
. . . . . . . . . . . . 6.0 Installation Clearances
8 . . . . . . . . . . . 7.0 Wall Mounting
. . . . . . . . . . . . 8.0 Gas Connection
9 . . . . . . . . . . . 9.0 Water Connections
. . . . . . . . . . . 10.0 Condense Waste Connection
10 . . . . . . . . . 10.0 Condense Waste Connection (contd)
. . . . . . . . . . . 11.0 Flue Combustion Air Connection - General
11 . . . . . . . . . 12.0 Conventional Flue Installation
12-18 . . . . . . . 13.0 Room Sealed Flue Installations
19 . . . . . . . . . 14.0 Examples of Calculating Flue Pressure Loss
20 . . . . . . . . . 14.1 Calculating Flue Resistance
. . . . . . . . . . . 15.0 Flue Terminal Positions
21 . . . . . . . . . 15.0 Flue Terminal Positions (contd)
22-23 . . . . . . . 16.0 Ventilation Requirements Single Appliances
24-33 . . . . . . . 17.0 Hydraulic System Design (circuit diagrams)
33 . . . . . . . . . 17.1 Filling The System
. . . . . . . . . . . 17.2 Water Treatment System Cleaning
34 . . . . . . . . . 17.3 Care With The Use of Soldering Flux
. . . . . .17.4 Domestic Hot Water - Combi
. . . . . . . . . . . 17.5 Combi Boiler - Prevention of scale in
. . . . . . . . . . . . . . water to water heat exchanger
35-36 . . . . . . . 17.6 Combi Boiler Hot Water
. . . . . . . . . . . . . . System Pipework Pressure Drop
. . . . . . . . . . . 17.7 Combi Boiler - Domestic Hot Water
. . . . . . . . . . . . . . System Design Considerations
36-48 . . . . . . . 18.0 Electrical Connections
49 . . . . . . . . . 19.0 Commissioning The Strata 1 Boiler
. . . . . . . . . . . 19.1 Pre-Commissioning Checks
. . . . . . . . . . . 19.2 LPG Conversion Procedure
50 . . . . . . . . . 19.3 Control Panel
51-52 . . . . . . . 19.4 First Firing
52-54 . . . . . . . 19.5 Setting The Control Panel
54-60 . . . . . . . 19.6 Installer Programming of Control Panel
61 . . . . . . . . . 19.7 Output For Charging Hot Water
. . . . . . . . . . . 20.0 Setting The Boiler To Work
. . . . . . . . . . . 21.0 Servicing Instruction
. . . . . . . . . . . 21.1 Inspection
61-62 . . . . . . . 21.1 Inspection (contd)
. . . . . . . . . . . 21.2 Maintenance
63 . . . . . . . . . 21.2 Maintenance (contd)
63-65 . . . . . . . 22.0 Screen Display/Diagnosis Of Faults
65-66 . . . . . . . 22.1 (Possible) Causes Of Fault & Corrective Action
67 . . . . . . . . . 23.0 Instructing The User
. . . . . . . . . . . 23.1 To Turn on the Appliance
. . . . . . . . . . . 23.2 To Turn off the Appliance
68-70 . . . . . . . 24.0 Parts List

3
STRATA1
38 & 38/46 COMBI
1.0 general
notes
These instructions are intended to assist the installer, commissioning engineer, maintenance engineer
and user with the installation, maintenance and usage of the Strata 1-38 gas fired condensing boiler and the
Strata 1-38/46 gas fired condensing combination boiler.
Please read this manual fully before commencing the installation of the appliance. The Strata 1 must
only be installed by persons deemed to be competent i.e. Corgi Registered. This manual must be handed
to the appliance user following completion of the installation. The appliance must not be left to operate
with the outer casing removed.
conformity statement
Strata 1 38 & 38/46 Combi boilers are manufactured to the highest standard of quality, performance
and safety, in accordance with EC standards. Strata 1 45, 60 & 75 boilers carry the CE mark
installation requirements
The installation of Strata 1 boilers must be in accordance with the relevant requirements of Gas Safety
(Installation and Use) Regulations 1994, Health & Safety at Work Act, Building Regulations, I.E.E.
Regulations, Construction (Design & Management) Regulations 1994, Local Authority Bye-Laws, Local and
National Water Bye-Laws, Fire Authority Regulations and Insurance Company requirements.
The following Codes of Practice are also applicable:-
• BS6798: 1987 Specification for installation of gas fired hot water boilers of rated input not
exceeding 60kW.
• BS6880 Code of Practice for low temperature, hot water heating systems of output greater than
45kW. Parts 1, 2 and 3: 1988.
• CP342 Part 2: 1974 Code of Practice for centralised hot water supply.
• BS6644 1991 Specification for gas fired hot water boilers of rated inputs between 60kW and 2MW.
• IGE/UP/2 Gas installation pipework, boosters and compressors on industrial and commercial
premises.
• CIBSE Guide Reference sections B7, B11 and B13.
• BS5440 Installation of flues and ventilation for gas appliances of rated input not exceeding 60kW.
Part 1: 1990 Specification for the installation of flues.
• BS5440-2: 2000 Installation and maintenance of flues and ventilation for gas appliances of rated input
not exceeding 70kW net (1st, 2nd and 3rd family gases) Part 2: Specification for installation and
maintenance of ventilation for gas appliances.
• IGE/UP/10 Installation of gas appliances in industrial and commercial premises. Part 1: Flued appliances.

4
STRATA1
38 & 38/46 COMBI
2.0 product
description
The Strata 1 range of wall mounted gas fired condensing boilers are state of the art appliances which
include a comprehensive range of features. The appliance must only be used on sealed and pressurised
systems. System design must take into account the boiler operating ∆t of 20°C.
wall mounted with compact dimensions
At 900H x 458W x 355D, the Strata 1 boiler provides maximum heat from minimum dimensions
without compromising serviceability.
fully modulating heat output
The output of the boiler is fully variable, sliding between (approx.) 20% to 100%, which automatically
and instantly adjusts to match the needs of the system. The percentage of power at any given time can be
dictated by either outside air temperature, flow temperature, return temperature, stored or instantaneous
domestic hot water temperature, or room temperature, or a combination of the aforementioned.
fully condensing stainless steel heat exchanger
The Strata 1 boiler is designed with extended heat exchange surface area and is fabricated from
corrosion resistant long-life stainless steel. The unique Spiranox heat exchanger will return operating
efficiencies from 88% gross (96% nett) at 60°C return temperature, up to 96% gross (104% nett), at 30°C
return temperature.
extremely low harmful emissions
The boiler utilises 100% pre-mix gas/air fed at positive pressure to the metal fibre sheathed radiant
burner. The combustion system incorporates internal flue gas re-circulation and this combined with the
precise nature of pre-mix fuel/air control, gives ultra low emissions to satisfy the most stringent emission
regulations in the world currently. That is: < 20mg/kWh NOx (14 ppm DAF) and < 14mg/kWh CO (13
ppm DAF). The fully modulating nature of the appliance also reduces emissions by avoiding repeated
start/stops and the associated increase in emissions, which occurs with burner on/off cycling.
accurate variable burner output control
The pre-mix burner fan has a low voltage direct current drive motor with pulse relay counting. This
system allows precise control over fan speed/combustion air volumes. Coupled with a gas valve system set
to provide proportionately measured volumes of fuel to air, this allows extremely accurate and instant
variable burner output control to be achieved.
high domestic hot water flow rate – combi boiler
The combi boiler includes a high performance water to water heat exchanger which coupled with a
variable output up to 46kW provides up to 0.21 l/s of hot water raised through 50°C. The water to water
heat exchanger contains 10 litres of primary water which is maintained at the required domestic hot water
temperature so ensuring prompt delivery of hot water.
energy saving
In addition to the extremely efficient burner and heat exchanger system employed in the Strata 1, each
appliance includes a modulating speed boiler primary pump.
This feature allows the boiler to self-maintain a 20°C ∆t across the heat exchanger, optimising the heat
exchanger efficiency and reducing also the electrical consumption of the pump motor. The result is a
seasonal increase in boiler efficiency of a further 7-10% and a reduction in pump electricity consumption of
up to 70%.

5
STRATA1
38 & 38/46 COMBI
2.0 product description (contd)
natural gas or LPG
Appliances can be supplied for use with natural gas (G20) or LPG (G31).
comprehensive microprocessor control
The boiler control panel includes a user friendly microprocessor control centre which manages the
entire function of the appliance and encompasses:-
1. Management of the essential safety functions of burner ignition and flame monitoring.
2. Water high temperature and flue gas high temperature safety cut out.
3. Modulation of the boiler output and pump speeds in conjunction with operating temperature control.
4. LCD display screen with two lines of text to continuously display operational or fault status.
5. In built weather compensator to provide direct-on boiler VT flow temperature (if required).
6. Remote stored hot water temperature control and when using optional temperature sensor gives the
option of regular anti-legionella programme (not combi).
7. In built 2 stage boiler frost protection program.
8. In built pump exercising program to avoid standstill seizure.
9. Cold start boost facility.
10. PC compatibility with data logging which allows communication with the boiler via a lap-top computer
to review/modify operational parameters and access operational history as an aid to fault finding and
preventative maintenance.
11. Range rate adjustment which allows the power to be set to accurately match the maximum needs of
the system, with the facility to set a different firing rate for heating. Output to hot water self adjusts to
the heat transfer capability of the calorifier or the instantaneous demand (combi boiler).
12. Facility to connect optional matched control components which allow the boiler to control a heating
circuit pump, *HWS primary pump or *diverter valve and an underfloor circuit mixing valve and pump,
(MR03) plus the ability for the boiler to be controlled by a remote multi function modulating room unit.
(RE2132) Multiple boilers may be connected to a modulating Kaskade manager (KKM2) or controlled
via a 0-3 or 0-10v* signal (*via adaptor) which further enhances the operating efficiency of a larger load
modular boiler system. (*Not combi).
13. Inbuilt time switch (3 on - 3 off/24hr) for heating control and *separate channel for hot water time
control. (*Not combi).
room sealed option
If required, the boiler may be installed to be completely room sealed, taking combustion air directly
from outside the building, using a 125/80 concentric air duct/flue duct system. Inherent safety is afforded
by the negative pressure within the boiler casing, which in the event of incorrect sealing results in safe
inward air leakage only.
extended flue lengths
The excess fan pressure from the combustion system is 100 Pa, which allows the appliance to be
exhausted using small diameter PPS plastic flue components, over long distances, allowing for complete
flexibility in boiler siting.
designed for ease of maintenance
Although compact, the Strata 1 does not compromise serviceability. The appliance has been engineered
to be easy to maintain with even the most major of service operations being able to be completed easily
and quickly with the minimum of tools.
guarantee
The heat exchanger carries a five year guarantee against manufacturing or material defect. All other
parts carry a one year warranty against manufacturing or material defect.

6
STRATA1
38 & 38/46 COMBI
3.0 technical data
& dimensions
Dimensions in millimetres
229
458
155
355
3
4
6
7
8109
5
60
60
60
110
50
50
950
front view
plan view
underside - 38/46 combi
145 145
100 100
40
1
2
38/46 Combi
DN125
DN80
22mm
22mm
22mm
22mm
3/4" BSP-M
15mm
—
—
38
DN125
DN80
22mm
—
—
22mm
3/4" BSP-M
15mm
—
—
Connection Strata 1
1. Combustion Air Inlet
2. Flue Gas
3. Flow
4. Hot Water (Out)
5. Cold Water (In)
6. Return
7. Condense Waste Outlet
8. Gas Connection
9. Condense Syphon Cleaning Point
10. Glanded Cable Entries
Model Strata 1
Input Range Central Heating Net kW
CH Modulating Output 80/60°CkW
CH Modulating Output 50/30°CkW
Min Working Pressure CH Bar
Max Working Pressure CH Bar
Max Flow Temperature CH °C
Total Primary Capacity Litre
Available CH Pump Pressure at kPa
38kW & 20°C ∆t
Input Range Domestic Hot Water Net kW
HW Modulating Output kW
Domestic Hot Water Flow at 50°∆t l/min
Domestic Hot Water Flow at 35°∆t l/m
Max Working Pressure Bar
Domestic HW
Max Flue Gas Volume (Hot) m3/h
Gas Consumption (Nat Gas G20) m3/h
Min/Max Gas Inlet Pressure mbar
Average Electrical Consumption Watts
Power Supply V
Weight Empty kg
38/46 Combi
6.4 - 36.0
6.2 - 34.6
7.0 - 37.8
0.5
3.0
85
12.4
23.5
6.4 - 46.0
6.4 - 46.0
13.14
18.77
10.0
65.13
0.68 - 4.77
18/60
60
230
50
38
6.4 - 36.0
6.2 - 34.6
7.0 - 37.8
0.5
3.0
85
2.4
32.5
6.4 - 46.0
6.4 - 46.0
—
—
—
65.13
0.68 - 4.77
18/60
60
230
39
underside - model 38
100 100
145 145
40
50
60
10 3 10 8 67
9

4.0 delivery consignment
/unpacking the boiler
The boiler is delivered as a consignment of a palleted carton containing the boiler and associated
fittings, plus any other optional ancillary flue or control components in separate cartons.
The boiler carton contains:-
●Assembled boiler.
●Wall mounting bracket.
●Fittings bag including: condense waste outlet hose union assembly, outside air temperature sensor c/w
wall fixings and 1/2" BSP inlet 3/4" BSP outlet safety pressure relief valve set 3 bar.
To unpack the boiler, the palleted carton should be laid on the floor. Carefully cut the nylon bands and
lift away fibre board protective panel. Open carton top and lift out wall hanging bracket and fittings bag.
Remove packing material and lift away bottomless carton. With 2 men, carefully lift boiler from palette by
holding grey rear chassis only.
To remove the casing from the boiler, slacken the screw in the underside of the casing, unlatch left and
right hand catches on underside of case, pull casing slightly to the front and lift upwards to disengage casing
hooks from rear chassis and then remove casing to the front.
5.0 boiler
location
The Strata 1 Boiler is not suitable for installation external to a building. The position chosen for the
boiler must be a structurally sound wall capable of supporting the weight of the boiler and any ancillaries.
The position should allow for access to a condense waste drain nearby or an alternative is to install a
condense sump receptacle and condense disposal pump which should remove the condense waste water
to a remote drain. The wall mounting position of the boiler must allow the boiler to be true plumb vertical
to ensure correct operation of the internal gravity flow condense system. The position for the boiler must
satisfy the requirements of BS6798:1987 or BS6644:1991 as appropriate.
6.0 installation
clearances
For ease of installation, commissioning and maintenance the following minimum clearances should
be observed:-
Sides 50mm
Above 250mm
Below 150mm
Front 450mm
STRATA1
38 & 38/46 COMBI
7

8
STRATA1
38 & 38/46 COMBI
7.0 wall
mounting
The Strata 1 boiler mounts to the wall
via a wall mounting bracket which interlocks
to a rail mounted upon the rear of the boiler.
The wall mounting bracket should be firmly
fixed to the wall using suitable fixings. The
wall mounting bracket positioning detail is
shown in fig 1. The boiler must be carefully
offered up to the wall so that the rail on the
rear of the boiler is just above the wall
mounting bracket and then the boiler should
be lowered to engage the bracket and rail.
Lifting is advised with 2 persons. Do NOT
lift the boiler by the internal parts of
the appliance.
Important Note
When viewed from the side, the
north/south axis of the boiler must be
vertical. The appliance must not be inclined
out from the top, if necessary adjust the
positioning of the boiler using the adjustable
wall bearing assemblies located at the
bottom rear left and right hand of the
appliance back panel.
8.0 gas
connection
The gas connection is located at the base
of the appliance rear centre, see fig 2.
The pipe size used to supply the
appliance must not be smaller than the gas
connection size on the appliance.
The connection to the appliance
must include a suitable method of
disconnection and a gas control cock must
be installed adjacent to the appliance for
isolation purposes.
The gas pipe used to supply the
appliance must not allow a pressure drop
of greater than 1mbar from the meter to
the appliance.
The nominal inlet working gas pressure
measured at the appliance should be
20.0 mbar for Nat Gas (G20) or 37 mbar for
LPG (G31). The installer should install a
pressure test point adjacent to the gas
inlet connection.
458
165
3 x ø7.0
165
797 900
103
50
Gas Connection
15mm
Fig 2.
Fig 1.

Note the Strata 1 boiler must only be installed on sealed and pressurised systems. The maximum
working pressure of the boiler = 3 bar. A safety valve set 3.0 bar is supplied with the boiler and must be
installed onto the flow pipe adjacent to the boiler. It is recommended that the final working pressure (hot)
of the system does not exceed 2.3 bar. Note –the appliance does NOT include an expansion vessel. A
suitable vessel must be connected to the system.
The central heating flow and return connections are 22mm OD, located at the base of the appliance
(see fig 3) and should be connected to the system pipework using compression type fittings. DO NOT
make soldered connections onto the appliance.
The COMBI BOILER includes domestic hot and cold water connections located at the base of the
appliance see fig 4. These connections are 22mm and should be connected using compression type fittings.
DO NOT make soldered connections onto the appliance.
The flow, return and domestic cold supply pipework should include isolation valves and all pipes should
include means of disconnection.
9
9.0 water
connections
10.0 condense
waste connection
The condense waste connection is located at the underside rear of the appliance see fig 5.
The condense syphon cleaning point is factory fitted with a heavy grade black plastic cap which MUST
NOT BE REMOVED (see fig 5) apart from routine maintenance cleaning operations and must be in place
whenever the appliance is in operation. WARNING operating the appliance with the cap removed from
the syphon cleaning point will cause products of combustion to be discharged from the cleaning point.
The condense waste connection is a 3/4" BSP Male threaded stub fabricated from
plastic. The installer must connect to this stub, a condense waste pipe fabricated
from plastic tube and fittings (3/4", 22mm, overflow pipe is considered suitable).
Copper Tube is not acceptable. The condense waste pipe must fall continuously
from the appliance to suitable nearby drain.
If any part of the condense waste pipe is to be run external to the building or is at risk of freezing, then
the pipe must be suitably insulated to protect from freezing.
If a suitable drain for accepting the condense waste is not available nearby to, and below the boiler, (e.g.
boiler installed in a basement below ground level location), then a suitable condense sump receptacle with
a discharge pump should be installed below the boiler to remove the condense to a remote drain.
STRATA1
38 & 38/46 COMBI
Flow
22mm
Fig 3. Fig 4.
Return
22mm
Cold Water
Inlet 22mm
Combi only
Hot Water
Outlet 22mm
Combi only

10
STRATA1
38 & 38/46 COMBI
10.0 condense waste
connection (contd)
Fig 5.
Condense
Waste
Connection
Syphon Cleaning
Point Must
Remain Capped
When making the condense waste pipe
connection to the boiler, do not use adhesives, it is
recommended to lightly apply a suitable jointing
tape (PTFE or similar) and use only light pressure to
connect fittings to the appliance to avoid damage to
the condense waste outlet assembly.
It is recommended that the condense waste
pipework should include a method of disconnection
and cleaning points.
11.0 flue/combustion
air connection - general
The flue connection and combustion air inlet to the appliance are located on the top of the appliance
see fig 6. These connections are arranged concentrically with the 80mm flue gas connection centrally within
the 125mm air inlet connection.
There are two options for flueing the Strata 1 boiler:
i) Conventionally, using flue gas tube only and air for combustion from the room or compartment
in which the appliance is installed. If using a conventional flue arrangement then the room or
compartment must be ventilated in accordance
with the requirements of BS5440. For guidance
on ventilation see section 16.
ii) Room sealed using concentric 80/125
components or two seperate tubes, where air
for combustion is taken from outside of the
building. When using a room sealed flue, where
air for combustion is provided from outside of
the building directly to the appliance, ventilation
to a compartment may still be required - See
section 16 for general space cooling.
Multiple Boilers
For detail and advice on common flues serving
multiple boilers, contact MHS Boilers Ltd.
Important Note
Where the Strata 1 is to be installed in
an application where the combustion air is
likely to be contaminated with oxidising
agents, such as swimming pool areas, special
industrial processes etc, then the appliance
must be room sealed.
Air Inlet
Flue Gas
Connection
Fig 6.
typical modular
flue arrangement
Inspection
Area

11
STRATA1
38 & 38/46 COMBI
12.0 conventional
flue installation
The Strata 1 boiler has an excess pressure combustion system, which coupled with the very low flue
gas temperatures produced allows the appliance to exhausted over considerable distances using 80mm
Polypropylene PPS flue pipe and fittings. Suitable flue pipe and fittings are available from MHS Boilers Ltd
and are listed below.
The flue should be installed to have at least a 3°fall to the boiler to allow any condense formed in the
flue to run back to the boiler.
The flue system used must be gas and water tight and must be adequately supported over it’s entire
length. Support at 1 metre intervals. It is not necessary to install a terminal to the flue system, however, a
mesh guard should be included to prevent blockage or entry of foreign material. Straight lengths may be
cut to size with any surplus cut from the plain end. Tube ends should be cut square and de-burred.
Care should be taken when selecting a position for a low level discharge or discharge adjacent to
windows etc as the flue terminal will plume heavily and the white water vapour discharge may cause a
visual nuisance.
Flue components available from MHS Boilers Ltd
80 mm PPS Flue Tube x 1000 mm long
(effective length 945 mm)
80 mm PPS Flue Bend x 93°
80 mm PPS Flue Bend x 45°
80 mm Wall Fixing Bracket - Aluminium
80 mm Bird Mesh Cap - Plated Steel
The above flue components
are light grey self coloured
Polypropylene moulded com-
ponents with push together
spigot and socket joints
with integral seal ring located in
the socket.
If fire stop seals are required
to be installed where PPS plastic
flue components pass through
walls, floors or ceilings then
suitable fire stop seals are
available from:-
Nullifire Ltd
Torrington Avenue
Coventry CV4 9TJ
Tel [phone]
Fax [phone]
Dufaylite
Developments Ltd
Cromwell Road, St Neots
Huntingdon PE19 1QW
Tel [phone]
Fax [phone]
Quelfire
PO Box 35, Altrincham
Cheshire WA14 5QA
Tel [phone]
1000 mm
Effective Length 945mm
137
125
ø80
ø80
50
65 75
ø80 50
100
150
50
80 øPPS
Flue Tube
x 1000
long
80 ø
PPS Flue
Bend
x 93º
80 ø
PPS Flue
Bend
x 45º
80 øWall
Fixing Bracket
ø5 Woodscrew
fitting
100 mm PPS Flue Tube x 1000 Long (Effective Length 945 mm)
100 mm PPS Flue Bend x 93°
100 mm PPS Flue Bend x 45°
100 mm Wall Fixing Bracket
100 mm Bird Mesh Cap - Plated Steel
80 x 100 mm Increaser
80 øPPS flue components
100 ID
56
50
150
80 x 100 PPS
Increaser
End Slip
80

12
STRATA1
38 & 38/46 COMBI
13.0 room sealed
flue installations
The Strata 1 boiler has an excess pressure combustion system, which coupled with the very low flue
gas temperatures produced allows the appliance to be exhausted and supplied with room sealed
combustion air using a concentric flue arrangement of 80 mm PPS polypropylene flue pipe within a 125 mm
outer painted metal air tube over considerable distances. A range of concentric flue components are
available from MHS Boilers Ltd and are listed below. Alternatively, two seperate tubes, one carrying
combustion air and one carrying flue gas may be used in conjunction with the appropriate adaptor.
The concentric flue system should be installed to have at least a 3°fall to the boiler to allow any
condense formed in the flue to run back to the boiler.
The flue system must be gas and water tight and must be adequately supported over it’s entire length.
Support at 1.5m intervals. Horizontal Discharge and Vertical Discharge Terminal Sets are available.
Care should be taken when selecting a position for a low level discharge or discharge adjacent
to windows etc as the flue terminal will plume heavily and the white water vapour discharge may cause a
visual nuisance.
Concentric flue components have push together spigot and socket joints. Both the inner PPs flue gas
tube and the outer air tube have soft seal rings located in the socket components.
To aid assembly and assurance that the joints have been fully pushed home, the seal rings and make
ends of tubes/fittings should be lightly lubricated with silicone grease.
list of concentric flue components
●80/125 concentric wall terminal set:- comprises 845 mm straight length with made on terminal, 90°
concentric bend and wall bezel plates.
●80/125 concentric roof terminal set:- comprises 1000 mm straight length with made on terminal and
1Nr 125 wall bracket.
●125 pitched roof tile flashing for use with concentric roof terminal set, adjustable between 25°to 50°.
●125 flat roof flashing for use with concentric roof terminal set.
●80/125 concentric flue tube set x 1000 mm.
●80/125 concentric flue tube set x 500 mm.
●80/125 concentric 93°bend.
●80/125 concentric 45°bend.
●125 Wall bracket assembly.
●80/125 concentric vertically extendible discharge room sealed wall terminal assembly (610 mm long
(*850) - For use where a standard wall terminal may cause visual flue gas pluming nuisance. Includes 90°
Concentric bend, wall bezel plates and silicone mastic. Used in conjunction with additional 80 mm pps
flue gas tube and fittings listed on page 10.
●80/125 concentric to 2 x 80 mm separate tubes adaptor.
●80/125 to 100/150 concentric increaser (not shown).
●100/150 concentric wall terminal (not shown).
●100/150 concentric roof terminal (not shown).
●100/150 concentric flue tube set x 1000 mm (not shown).
●100/150 concentric flue tube set x 500 mm (not shown).
●100/150 concentric 93°C bend (not shown).
●100/150 concentric 45°C bend (not shown).

13
STRATA1
38 & 38/46 COMBI
13.0 room sealed flue installations (contd)
497
1000
Effective Length 950 mm
994
Effective Length 450mm
125 80
125
110
75
40
75
40
80
178
75
ø7mm "Drive In"
Fixing C/W Wall Plug
90
125
125
110
40
40
80
125
93º
80
80/125
Concentric
Tube x
500mm
80/125
Concentric
Bend x 45º
ø125 Wall
Fixing
Bracket
80/125
Concentric
Tube x
1000mm
80/125
Concentric
bend x 93º
491
80/125 concentric roof terminal & accessories
80/125
Concentric
Roof
Terminal
Assembly
80
125
1170
513 513
130
390
500
500
Circular 125 Spun
Aluminium Flat Roof
Flashing
Pitched Roof
Flashing - Adjustable
25-38º& 37-50º
125 Pitched Roof
Adjustable Flashing.
Adjustable between 25-38º
and 37-50º
Lead Apron 1.3mm
458
229
355178900
155
120
80 80
plan
80/125
Concentric
to 2 x 80 mm
Tubes
Adaptor
Flue
Gas Air for Combustion

14
STRATA1
38 & 38/46 COMBI
13.0 room sealed flue installations (contd)
installation of standard wall terminal
In order to determine the length of concentric tube required to correctly terminate a side outlet
arrangement, the following procedure should be followed:
1. Measure wall thickness W in mm - see fig 7.
2. Measure distance between side of appliance and inside face of wall L1 in mm see fig 7.
3. Mark off and cut flue tubes following guidance shown in fig 8 below. Flue tubes should be cut to length
TL in mm. Both inner and outer tubes should be cut flush with each other, square and any
burrs removed.
Where TL required, is greater than 845 mm, then additional lengths (as appropriate) of 80/125
concentric tube will be required to extend the standard wall terminal. A fall of 3˚is required along the
length of the flue towards the appliance.
detail for marking out for
cutting flue hole for side flue,
room sealed horizontal
arrangement
Cut Flue Hole
ø130mm
Line-Top of
Appliance Chassis
155
170
side outlet
170
L1
W
Plain
Section
Installed
Uppermost
Wall Bezel
Plates
Required Length
Cutting Line measure from
this point
TL (mm)
TL = W+L1+235mm
concentric wall terminals
945
610
850*
845
Standard Horizontal
Discharge Wall Terminal
(supplied with 80/125
Concentric 90ºbend and
wall bezel plates not
shown)
Horizontal Wall Terminal
With Extendible Vertical
Discharge (supplied with
80/125 Concentric 90º
bend and wall bezel plates
not shown)
ø125
ø80
ø125
ø80
Fig 7.
Fig 8. Fig 9.
side outlet
(3˚fall to
appliance)

15
STRATA1
38 & 38/46 COMBI
installation of standard wall terminal
In order to determine the length of concentric tube required to correctly terminate a rear outlet
arrangement, the following procedure should be followed.
1. Measure wall thickness W in mm - see fig 10.
2. Mark off and cut flue tubes following guidance shown in fig 11 below.
Flue tubes should be cut to length TL in mm. Both inner and outer tubes should be cut flush with each
other, square and any burrs removed.
Where TL required, is greater than 845 mm, then additional lengths (as appropriate) of 80/125
concentric tube will be required to extend the standard wall terminal. A fall of 3˚is required along the
length of the flue towards the appliance.
13.0 room sealed flue installations (contd)
rear outlet rear outlet
170
W
Plain
Section
Installed
Uppermost
Wall Bezel
Plates
Required Length
Cutting Line measure from
this point
TL (mm)
TL = W+161mm
170
c
L
cut flue hole
ø130
detail for marking
out for cutting
flue hole for
rear flue, room
sealed horizontal
arrangement
Fig 10. Fig 11.
Fig 12.

16
STRATA1
38 & 38/46 COMBI
method of assembly of horizontal concentric flue
system using standard wall terminal
1. Lubricate male ends of concentric bend
with silicone grease and locate bend into
flue and air tube connection sockets on
the top of the boiler and gently push
fully home.
2. Slip flue tube and terminal assembly
through prepared hole in the outside wall.
3. Locate wall bezel plate loosely onto
air tube.
4. Lubricate male ends of concentric flue
tube and female sockets of flue bend
lightly with silicone grease. Insert
concentric tubes into bend and gently
push fully home. Ensure plain section
of external part of air inlet tube is
located uppermost.
5. Make good internally and externally gap
between air tube and prepared hole
through wall.
6. Slip on external wall bezel plate.
7. Fix internal and external wall bezel plates with fixings provided.
Where a flue terminal discharges through a wall within 2m of ground level or balcony etc then
the terminal should be fitted with an appropriate sized terminal guard to prevent that the terminal may
be touched.
extending the flue gas discharge vertically away
from a room sealed wall terminal
The Strata 1 boiler is a fully condensing appliance with very low flue gas temperatures. Consequently,
the flue gas discharge is commonly seen as a white vapour plume, Whereas this is not harmful when
properly discharged into the atmosphere outside of a building from a correctly operating appliance, the
white vapour plume may cause, in certain applications a visual nuisance.
It must also be considered that a flue termination will drip condense water and may cause an ice hazard
below the terminal position
If it is considered that pluming or dripping from the end of a standard wall terminal may create a
nuisance, then as an alternative, the vertically extendible discharge wall terminal is available see figs 14 and
16. This creates a local room sealed intake for combustion air but allows the installer to extend the 80 mm
PPS flue gas tube to a point where pluming or dripping discharge will not cause a visual nuisance or hazard.
installation of vertical discharge wall terminal
In order to determine the length of concentric tube required to correctly terminate a side outlet
extended vertical discharge arrangement, the following procedure should be followed.
1. Measure wall thickness W in mm - see fig 14 overleaf.
2. Measure distance between side of appliance and inside face of wall L1 in mm - see fig 14 overleaf.
3. Mark off and cut flue tubes following guidance shown in fig 15 overleaf. Flue tubes should be cut to
length TL in mm. Both inner and outer tubes should be cut flush with each other, square and any
burrs removed.
Where TL required, is greater than 610 mm, (*850mm) then additional lengths (as appropriate) of
80/125 concentric tube will be required to extend the vertical discharge wall terminal. A fall of 3˚is
required along the length of the flue towards the appliance.
13.0 room sealed flue installations (contd)
13
4
6
2
Plain
Section
Uppermost
Fig 13.

17
STRATA1
38 & 38/46 COMBI
installation of vertical discharge wall terminal
with rear outlet
In order to determine the length of concentric tube required to correctly terminate a rear outlet
extended vertical discharge arrangement, the following procedure should be followed.
1. Measure wall thickness W in mm - see fig 16.
2. Mark off and cut flue tubes following guidance shown in fig 17 below.
Flue tubes should be cut to length TL in mm. Both inner and outer tubes should be cut flush with each
other, square and any burrs removed.
Where TL required is greater than 610 mm, (*850) then additional lengths (as appropriate) of 80/125
Concentric tube will be required to extend the vertical discharge wall terminal. A fall of 3˚is required along
the length of the flue towards the appliance.
installation of vertical discharge wall terminal
with side outlet
170
W
ø80 PPS
90ºBend
ø80
Bird Mesh
ø80
PPS Tube
Exhaust
Outlet
Installed
vertically
Upwards
on same
wall aspect
Wall Bezel
Plates
Required Length
Cutting Line measure from
this point
TL (mm)
TL = W+262mm
side outlet
170
W
ø80 PPS
90ºBend
ø80
Bird Mesh
ø80
PPS Tube
Exhaust
Outlet
Installed
vertically
Upwards
on same
wall aspect
Wall Bezel
Plates
Required Length
Cutting Line measure from
this point
TL (mm)
TL = W+L1+260mm
Fig 14. Fig 15.
side outlet
rear outlet rear outlet
Fig 16.
Fig 17.
13.0 room sealed flue installations (contd)

18
STRATA1
38 & 38/46 COMBI
method of assembly of extendible vertical
discharge wall terminal assembly
See fig 18.
1. Lubricate male ends of concentric bend with silicone grease and locate bend into flue and air tube
connection sockets on the top of the boiler and gently push fully home.
2. Slip flue tube and terminal assembly through prepared hole in the outside wall.
3. Locate internal wall bezel plate loosely onto air tube.
4. Lubricate male ends of concentric flue tubes and female sockets of flue bend lightly with silicone
grease. Insert concentric tubes into bend and gently push fully home. Ensure flue gas discharge is
positioned vertically upwards.
5. Made good internally and externally gap between air tube and prepared hole through wall.
6. Fit external 2 piece wall bezel and secure both internal and external wall bezels using fixings provided.
7. Seal air tube to exhaust discharge with a bead of silicone rubber mastic (mastic supplied) to create
weather seal to avoid entry of rain water into air tube.
8. Extend flue gas discharge to chosen position using 80 mm PPS flue tube fittings. Flue gas discharge must
discharge on same face of building as air inlet to avoid wind caused imbalance in flue system.
1
7
6
2
4
3
Extend using 80ø
PPS tube
Flue discharge Vertically
upwards on same wall aspect
8
Fig 18.
13.0 room sealed flue installations (contd)

19
STRATA1
38 & 38/46 COMBI
14.0 examples of calculating
flue pressure loss
example 1
A Strata 1-38/46 combination boiler is proposed to be
installed with a room sealed concentric flue taking an all
horizontal route to a wall terminal that has the flue gas
duct extended to a more acceptable termination position
to avoid a potential visual nuisance problem with flue
gas pluming.
Flue system comprises:
3 x 90°concentric bends
8 metres concentric flue tube
3 x 80mm 90°flue gas elbows
3 metres 80mm flue gas tube
Concentric wall terminal
Resistance =
1 x 80/125 concentric wall terminal @ 5.0 Pa = 5.0
3 x 80/125 90°concentric bends @ 4.0 Pa = 12.0
8 x 1m lengths 80/125 concentric tube @ 4.0 Pa = 32.0
3 x 90°DN80 bends @ 2.5 Pa = 7.5
3 x 1m lengths DN80 PPS tube @ 2.5 Pa = 7.5
1 x DN80 open termination with mesh @ 2.5 Pa = 2.5
Total Resistance = 66.5 Pa
conclusion: Total resistance is less than 100 Pa
therefore there will be no effect on boiler output. System
may be installed as proposed.
example 2
A Strata 1-38/46 combination boiler is proposed to be
installed with a room sealed concentric flue taking a part
horizontal (6m) and part vertical (10m) route to a vertical
concentric roof terminal set. The flue system includes 3
Nr 90°concentric bends and is installed to run within
the building.
Resistance =
3 x 80/125 90°concentric bends @ 4.0 Pa = 12.0
16 x 1m lengths 80/125 concentric tube @ 4.0 Pa = 64.0
1 x 80/125 concentric roof terminal with cap
@ 7.5 Pa = 7.5
Total Resistance = 83.5 Pa
There is 10 m of vertical flue which will create an
updraught of 33 Pa.
Therefore final operating resistance = 83.5 - 33 = 50.5 Pa.
conclusion: Total resistance is less than 100 Pa
therefore there will be no effect on boiler output. System
may be installed as proposed.
0
29
31
33
35
37
39
41
50 100 200150 250 300 350 400 450 500
Strata 1 - 38. 38/46 Combi
effect of flue
system resistance
on boiler output
Boiler Output kW at: Flow 80°C Return 60°C
Flue System Resistance - Pa
0 2 6 10 14 18 22 26 30 34 38
0
10
30
50
70
90
110
130
20
40
60
80
100
120
140
48 1612 20 24 28 32 36 40
thermal updraught when
flue gas temp 80°C and
outside temp -5°C
Draught - Pa
Vertical Flue Lengths - metres
A = Insulated or within the building
B = Uninsulated and exterior to the building
A
B

20
STRATA1
38 & 38/46 COMBI
14.1 calculating
flue resistance
If a flue terminal is positioned within 2 m above ground level or any upper part of a building where
people have general access (e.g. balcony etc) then the terminal should be fitted with an appropriate guard.
The flue terminal of a Strata 1 boiler will plume heavily and care must be taken when selecting a
terminal position to ensure that a "nuisance situation" is not created.
15.0 flue
terminal positions
flue terminal positions
H,I
J
N
A
G
F D
EA
Q
P
G
N
B,C
F
F
L
K
LK
N
M
7.5
7.5
11.25
5.5
5.5
2.75
5.0
5.0
2.5
7.0
2.0
2.0
1.0
4.0
2.0
3.5
4.0
4.0
2.0
Component.
80/125 Concentric Wall Terminal
80/125 Concentric Roof Terminal
Without Rain Cap
80/125 Concentric Roof Terminal
With Rain Cap
1m Length 80/125 Concentric Tube
93°80/125 Concentric Bend
45°80/125 Concentric Bend
1m Length DN 80 PPS Flue Tube (Fluegas)
93°DN 80 PPS Flue Bend (Fluegas)
45°DN 80 PPS Flue Bend (Fluegas)
Room Sealed Chimney Cap
1m Length DN 100 PPS Flue Tube
93°DN 100 PPS Flue Bend (Fluegas)
45°DN 100 PPS Flue Bend (Fluegas)
DN 80 Open Termination with Mesh
DN 100 Open Termination with Mesh
80/125 Concentric to 2 x 80 Tubes Adaptor
1m length DN80 PPS Tube (Air)
93°DN 80 PPS Bend (Air)
45°DN 80 PPS Bend (Air)
The excess pressure available for overcoming the
frictional resistance of a flue system is 100 Pa.
The adjacent table of flue component resistances
will assist the designer in calculating total flue system
frictional loss.
If the total installed flue system resistance exceeds 100
Pa, then the result will be a reduction in boiler output.
Reference to the “Effect of Flue System Resistance On
Boiler Output”, graphs will assist. If the resistance of a
proposed flue system has an unacceptable effect on boiler
output, then a larger diameter flue tube should be selected.
Thermal up-draught is generated in a vertical flue
system, reducing the resistance of the system. Reference to
the “Thermal Updraught Graph”will provide a figure in Pa,
which may be deducted from the total calculated flue
system resistance.
NOTE: Does not apply to horizontal sections of a flue system.
Resistance Pa
Strata 38 38/46
Fig 19.