Direct Storage Cylinders

Ancillary Items & Options

GMS Direct Cylinder
  • Control Valve: The control valve should be 2-port for steam and 2 or 3-port for water primary. A 3-port valve will maintain a fairly steady flowrate in the primary pipe-work whether the calorifier is using the primary water or not - this may be required on some systems. Control valves with a "double seat" to give higher throughput do not give guaranteed shut-off and should not be used for calorifier control.
  • High Limit Valve: If the control valve fails in the open position the calorifier will overheat. A high limit valve prevents this by shutting the primary fluid off if secondary temperature is excessive.
  • Pressure Relief Valve: Needed for all unvented calorifiers and where working pressure exceeds 25 m w.g.
  • Temperature/Pressure Relief Valve: For unvented systems there is a requirement for a temperature relief valve. This is usually combined in one unit with the pressure relief valve.
  • Pressure Gauge & Gauge Cock
  • Temperature Gauge
  • Anti-Vacuum Valve: Anti-vacuum valves are needed for all copper-lined steel calorifiers. They may also be fitted to copper calorifiers where there is a possibility of partial vacuum.
  • Automatic Air Vent: Normally only needed on unvented systems
  • Inspection Opening: Offered as standard unless specifically excluded. Inspection of the calorifier internal surface is possible when the tube bundle or immersion heater is withdrawn. If better facilities are required for inspection, or if construction is to BS853 (see below) then the inspection opening is required.
  • De-Stratification Pump and pipe-work: Timed to operate during periods of low demand, will ensure the complete heating of the calorifier contents at least once a day to kill legionella bacteria. We can offer a suitable pump and pipe-work assembly for new or existing calorifiers.
  • Sacrificial Anode: Except for unusually aggressive water a sacrificial anode is unnecessary. For galvanised calorifiers an aluminium anode is best. For copper calorifiers a magnesium anode would be offered.
  • Expansion Vessel: An expansion vessel should be connected to the cold feed pipe of unvented calorifiers.
Information Pages


     Some System Considerations

     Ancillary Items

     Thermal Insulation

     Design Standards

     Unvented Packages

Technical Documentation

     Download Data Book

     Download O&M Manual

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