Flues are an essential component for all gas fired boiler systems. They convey the harmful products of combustion to discharge to the atmosphere in a controlled and safe manner and depending on the type of system can also supply combustion air.
The Gas Regulations and manufacturer’s instructions must be adhered to in order to carry out this task safely.
There are two main methods of achieving safe discharge of exhaust flue gasses and provision of combustion air.
Open Flue
Where the products of combustion gases are taken to atmosphere through a single sealed pipe and the air for combustion is taken from the space where the boiler is fitted in this case, the room ventilation must comply with gas safe regulations
Room Sealed
Where the products of combustion are discharged to atmosphere in a sealed pipe and the air for combustion supplied directly into the boiler either by a pipe in pipe sealed pipe system (known as a concentric flue) where the inner pipe conveys flue gases out and the outer pipe conveys combustion air in or supplied by an completely separate sealed pipe which is known as a twin pipe system.
The flues can be manufactured from a variety of materials and there are several different designs to achieve an approved flue system. There is a comprehensive range of flues types available for Blade Water Heaters including Single Wall, Concentric, Twin Pipe, Cascade and Flexible Flue Lining Systems.
This is used for room sealed boilers where the exhaust gas and combustion air are conveyed in pipe in pipe arrangement. ( see separate Data Sheet and appropriate Installation Manual for further information) this type of flue is suitable for:
Premium and Premium Plus 30 and 40kW Blade Water Heaters.
Twin and Twin Plus 60 and 80kW Water Heaters
Horizontal Terminals
Vertical Terminals
This is used for room sealed boilers where the exhaust gas and combustion air are conveyed in pipe in pipe arrangement (see separate Data Sheet and appropriate Installation Manual for further information) this type of flue is suitable for:
Premium 50.70.90 and 115kW Water Heaters
Twin 100,140,180 and 230kW Water Heaters
Extensions
Bends
This is used where combustion air is taken from the space where the boiler is installed (see separate Data Sheet and appropriate Installation Manual for further information) suitable for:
Premium Plus 50,70,90 and 115kW Water Heaters
Twin Plus 100,140,180 and 230kW Water Heaters
Manifolds
Terminals
This is used where it is not possible to provide combustion air from the room where the boiler is installed and therefore one sealed pipe is used for exhaust gas and the other for combustion air in conjunction with our sealed system kit (see separate Data Sheet and appropriate Installation Manual for further information) suitable for:
Premium Plus 50,70,90 and 115kW Water Heaters
Twin Plus 100,140,180 and 230kW Water Heaters
Room Sealed Kit For Twin Pipe System
Extensions
Bends
This flue system can be used in multi boiler installations where the flues can be discharged locally into a larger common flue and then be run to atmosphere, these are specifically designed for each project and are sized to take into account flue length and number of appliances. All Blade Ranges can have Cascade Flues (see separate Data Sheet and appropriate Installation Manual for further information)
Typical Cascade System 4 Boilers
These are normally used in conjunction with the above open flue systems to line an existing chimney structure where other flue routes are impractical and undesirable. This will ensure the flue is to an approved standard for gas boiler exhausts (see separate Data Sheet and appropriate Installation Manual for further information)
Flexible Flue Lining Kit
It is critical that in modern low water content type condensing boilers, that BLADES use within our system, are maintained at the correct pressure. As these are sealed systems if the pressure drops below the specified level for any reason, then the boiler will not operate.
On smaller boilers below 45kW this can be undertaken manually using a filling loop, which allows a connection to be made between the water main and the boiler, this is normally only used on domestic type installations.
For boilers over 45kW it is compulsory to install a automatic system to maintain system pressure, but we would also recommend it for all types of commercial installations.
If required, we can supply a compact fully automatic pressurisation unit as an optional accessory. This unit can be easily fitted directly to the outside of our frame. We make allowance within our prefabricated installation for easy connections to be made to pipework and electrical systems. This unit will automatically keep the system at the correct pressure for the boiler.
The pressurisation unit should never be used to initially fill the boiler and a separate connection is provided within the BLADE frame for this purpose.
See data sheets below:
The BLADE WATER HEATERS are suitable for use on either gravity or mains pressure systems.
The gravity system will need the traditional gravity feed from a header tank and an open vent. However, if the cylinder is to be used with mains water pressure, then unvented cylinders will need to comply with Part G3 of the Building Regulations and therefore must be fitted with a mains cold water inlet control valve set and expansion vessel.
All these items are system specific and need to be designed to match the installation requirements. Therefore, we supply all necessary items to meet these regulations as optional accessories to suit each project, for the contractor to install in the appropriate location.
Each kit will contain the following:
Mains cold water expansion vessel sized to suit the cylinder system with wall mounting bracket.
Suitable sized pressure reducing valve, single check valve and Pressure relief valve
Blades can supply a range of sizes for these Expansion Vessels complete with Fixing Bracket:
12L Expansion Vessel (12EXP)
19L Expansion Vessel (19EXP)
24L Expansion Vessel (24EXP)
35L Expansion Vessel (35EXP)
50L Expansion Vessel (50EXP)
Blades can supply a range of Pressure Reducing Valves as part of the Unvented Cylinder Installation Kit the following sizes are available:
22mm Pressure Reducing Valve
28mm Pressure Reducing Valve
35mm Pressure Reducing Valve Set
42mm Pressure Reducing Valve Set
