Sealed system installation

The Greenstar Heatslave, designed for sealed systems, incorporates a pre-plumbed expansion vessel, pressure relief valve set to 3 bar (45psi), automatic air vent and pressure gauge. The expansion vessel fitted to the appliance will accommodate differing system volumes depending on initial charge pressure and system pre-pressurisation. Under certain circumstances the system volume may be in excess of that catered for by the expansion vessel provided. In this instance an additional vessel should be fitted as close as possible to the return connection of the appliance. Filling of the system can be from a make-up vessel, fitted with a non-return valve and mounted above the highest point in the system. Alternatively, and to comply with the new Water Authority requirements, the system may be filled through a temporary hose connection to the mains water supply provided that a double check valve assembly and test point are fitted on the system side of the temporary connection.

Radiator valves

Loss of water and drop in pressure from a sealed primary system will necessitate a continuous cycle of recharging with fresh water and consequential introduction of air - a corrosive element - into the system. In order to minimise leakage and prevent early corrosion it is important that all joints are good and all components are suitable for use in a sealed system. Particular care should be exercised when fitting radiator valves and only those of high quality to BS 2767:10 should be used.

Plastic pipework

• Any plastic pipe work used must have a polymeric barrier, comply with BS 7921 and installed to BS 5955 with 1000mm (minimum) length of copper or steel pipe connected to the boiler
• Plastic pipe work used for under floor heating must be correctly controlled with a thermostatic blending valve limiting the temperature of the circuits to approx. 50ºC with 1000mm (minimum) length of copper or steel pipe connected to the boiler

Primary system/connections/valves

• Do not use galvanised pipes or radiators.
• All system connections, taps and mixing valves must be capable of sustaining a pressure up to 3 bar.
• Radiator valves should conform to BS 2767:10.
• All other valves should conform to BS 1010.
• On new installations TRVs must be used on all radiators except the radiator where the room thermostat is sited, this must be fitted with lockshield valves and left open. All boiler replacement installations should have TRV’s fitted to radiators at least within the sleeping accommodation.
• Drain cocks are required at all the lowest points on the system.
• Air vents are required at all the high points on the system.