Technical data

9
4.2 boiler position (contd)
STRATA2
Where installation will be in an unusual location, special procedures may be necessary. BS6798 gives
detailed guidance on this aspect.
The unit cannot be used in the vicinity of chlorine, halogen or sulphur as may be the case in
environments such as swimming pools, coolant filling stations etc. In such cases the appliances MUST be
room sealed to take air for combustion from outside of the building.
● DN100 PPS tube x 1000mm
● DN100 PPS bend x 90°
● DN100 PPS bend x 45°
● DN100 wall bracket
● DN125 PPS tube x 1000mm
● DN125 PPS bend x 90°
● DN125 PPS bend x 45°
● DN125 wall bracket
● DN150 PPS tube x 1000mm
● DN150 PPS bend x 90°
● DN150 PPS bend x 45°
● DN150 PPS tee with 45° branch
● DN100 x 125 PPS increaser
● DN125 x 150 PPS increaser
● DN150 wall bracket
● 100/100 to 100/150 concentric adaptor
● 100/150 concentric tube x 1000mm
● 100/150 concentric bend x 90°
● 100/150 concentric bend x 45°
● 100/150 concentric horizontal terminal effective
length 975mm
● 100/150 concentric vertical terminal effective
length 500mm
● DN100 flat roof flashing
● DN100 pitched roof flashing
● DN125 flat roof flashing
● DN125 pitched roof flashing
● DN150 flat roof flashing
● DN150 pitched roof flashing
● Flat roof for 100/150 concentric terminal
● Adjustable pitched roof flashing for 100/150
concentric terminal
4.3 flue options &
terminal position
The Strata 2 has an excess pressure combustion system that allows the appliance to be exhausted over
extended distances using small OD flue components.
The flue gas temperature is extremely low (typically the same as the flow water temperature), which
allows the use of easy to install PPS (polypropylene) flue pipe and fittings.
The appliance can take combustion air from the room in which it is installed (conventional application)
or can be room sealed (fanned balanced flue) using a concentric flue arrangement of a 100mm PPS flue
duct within a 150mm galvanised metal air duct, finished in off-white RAL 7035. A full range of flue pipe and
air duct components including roof and wall terminals is available from MHS Boilers.
list of flue components
calculating flue resistance
The excess pressure available for overcoming the frictional resistance of a flue system is 100 P.a. The
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 P.a., 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 Up-draught Graph” will provide a figure in P.a., which
may be deducted from the total calculated flue system resistance.
Note: Does not apply to horizontal sections of a flue system.