The document is an installation, commissioning, and servicing instruction manual for the Worcester Greenstar i System, a wall-hung RSF gas-fired condensing boiler designed for sealed central heating systems and indirectly fed domestic hot water.
Function Description:
The Greenstar i System is a gas-fired condensing boiler that provides central heating and, when an optional internal diverter valve is fitted, domestic hot water. It is designed for use with Natural Gas (G20) or Liquid Petroleum Gas (LPG) and is classified as a Cat II 2H3P type C13, C33 & C53 appliance. The boiler incorporates a digital control system, FX Intelligent controls, and a modulating automatic gas valve to optimize performance and efficiency. It is pre-wired and pre-plumbed, featuring a galvanised steel inner frame for durability.
Important Technical Specifications:
The Greenstar i System is available in several models: 12i, 15i, 18i, and 24i, each with specific GC Numbers for Natural Gas and LPG variants.
- Gas Flow Rate (Max. 10 minutes from lighting):
- Natural Gas G20: 1.33 m³/h (12i), 1.63 m³/h (15i), 1.96 m³/h (18i), 2.67 m³/h (24i)
- Propane Gas (LPG): 0.96 kg/h (12i), 1.20 kg/h (15i), 1.44 kg/h (18i), 1.91 kg/h (24i)
- Central Heating (Net):
- Maximum Rated Heat Input: 12.32 kW (12i), 15.40 kW (15i), 18.48 kW (18i), 24.62 kW (24i) for both NG and LPG.
- Minimum Heat Input: 3.45 kW (12i NG), 4.62 kW (15i NG), 5.54 kW (18i NG), 7.38 kW (24i NG); 5.95 kW (12i LPG), 5.95 kW (15i LPG), 9.64 kW (18i LPG), 9.64 kW (24i LPG).
- Maximum Rated Heat Output (80/60 °C): 12 kW (12i), 15 kW (15i), 18 kW (18i), 24 kW (24i) for both NG and LPG.
- Maximum Flow Temperature: 82 °C.
- Maximum Flow Temperature to Cylinder (with integral optional diverter valve): 75 °C.
- Maximum Permissible Operating Pressure: 2.5 bar.
- Available Pump Head at 21 °C System Temp. Rise: 2.0 m.
- Flue:
- Flue Gas Temperature (80/60 °C, rated/min. load): Ranges from 62/56 °C (12i NG) to 79/64 °C (24i LPG).
- CO2 Level at Max. Rated Heat Output (after 30 min): 9.65% (12i NG) to 11.0% (LPG models).
- CO2 Level at Min. Rated Heat Output (after 30 min): 8.65% (12i NG) to 10.5% (LPG models).
- NOx Class: 5 (12i, 15i, 24i), 4 (18i).
- NOx Rating: 39 mg/kWh (12i NG) to 84 mg/kWh (18i NG/LPG).
- Condensate:
- Maximum Condensate Rate: 0.93 l/h (12i NG) to 2.0 l/h (24i NG); 0.7 l/h (12i LPG) to 1.5 l/h (24i LPG).
- pH Value (approx.): 4.8.
- Electrical:
- Power Supply Voltage: 230V a.c.
- Frequency: 50 Hz.
- Maximum Power Consumption: 140 W.
- General Data:
- SEDBUK Band: A.
- Appliance Protection Rating: IPX4D.
- Permissible Ambient Temperatures: 0-50 °C.
- Nominal Capacity of Appliance: 3.9 litres.
- Noise Output Level (Max central heating): 42 dBA.
- Packaged Boiler Weight: 41 kg.
- Total Boiler Weight: 37.5 kg.
- Lift Weight: 27.1 kg.
- SEDBUK Efficiency: 90.1% (NG models) to 92.0% (24i LPG).
- Dimensions: 700mm (height) x 400mm (width) x 330mm (depth to wall).
Usage Features:
- Automatic Ignition: Ensures reliable startup.
- Built-in Frost Protection: Protects the boiler from freezing temperatures.
- Built-in Fault Finding Diagnostics: Aids in identifying and troubleshooting issues.
- CH Temperature Sensor & Control: Allows for precise control of central heating temperature.
- Pump Anti-Seizure Protection: Prevents the pump from seizing during periods of inactivity.
- Condensate Syphonic Trap: Manages condensate drainage.
- Temperature Control: User-adjustable for central heating and domestic hot water (if diverter valve fitted).
- Optional Internal Diverter Valve: Enables domestic hot water functionality and control.
- Optional Programmer: Can be fitted for scheduled operation.
- Service Mode Button: Allows access to service functions for technicians.
- ECO Button (not used): Present on the control panel but not functional for this model.
- Reset Button: For resetting the boiler after a fault.
- System Pressure Gauge: Displays the system pressure.
Maintenance Features:
- Annual Servicing: Recommended by a competent, qualified Gas Safe registered engineer to maintain economy, safety, and reliability.
- Benchmark Checklist: Must be completed by the installer and service engineer after installation and each service.
- Component Access: The manual provides detailed instructions for removing the outer case, lowering the control panel to service position, and accessing various internal components.
- Gas Inlet Pressure Check: Procedure for measuring and verifying gas supply working pressure.
- Flue Integrity Check: Instructions for using a flue gas analyser to check O2 and CO2 levels to ensure proper flue system and combustion circuit performance.
- Fan Pressure Test: Procedure to determine if the heat cell requires cleaning/attention.
- Flue Gas Analysis (Combustion Test): Instructions for connecting a flue gas analyser and checking CO/CO2 readings against specified limits.
- Setting the Air/Gas Ratio (CO/CO2): Detailed procedure for adjusting the CO/CO2 levels at maximum and minimum output using a 4mm Allen key, ensuring CO is less than 200ppm. This must be carried out by a competent person with a combustion analyser.
- Cleaning the Heat Exchanger: Instructions for accessing and cleaning the heat exchanger, including removal of the fan, air/gas manifold, burner, and baffles. A special accessory cleaning kit is available.
- Syphon Cleaning: Instructions for draining debris from the syphon without full removal.
- Replacement of Parts: Detailed instructions for replacing various components, including the primary sensor, overheat thermostat, flue overheat thermostat, gas valve, air/gas manifold and fan assembly, fan, electrode assembly and burner, heat exchanger, auto air vent, pump head, drain tap, pressure gauge, hydraulic block, CH pressure relief valve, bypass valve, and expansion vessel.
- PCB Fuse Replacement: Instructions for replacing fuses on the PCB.
- Transformer/PCB Access: Instructions for accessing and removing the transformer/PCB.
- Diverter Valve Motor/Assembly Replacement (If fitted): Procedures for replacing these components.
- Water Treatment: Emphasizes the importance of cleaning primary systems according to BS7593 and adding a suitable inhibitor compatible with aluminium. Artificially softened water must not be used to fill the central heating system. The pH value of the system water must be less than 8.
- Condensate Pipe Work: Guidelines for installation, including minimum pipe diameter (22mm plastic), fall (50mm per metre), and termination methods (internal foul water discharge, waste pipe, or external soak away). Protection against freezing is emphasized.
- Pressure Relief Pipe Work: Guidelines for installing the pressure relief drain pipe (minimum 15mm copper pipe) to an external drain or soak away, ensuring it does not cause a hazard.
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