10.1.1 Start-up drains
Drain lines are provided to dispose of the condensate which collects during start-up. The drains may incorporate master and martyr valves in series. The master valve, located upstream, is normally open, but can be closed manually when isolation is required.
The martyr valve is motorised and, during normal operating conditions, provides adequate control for the start-up drains. In some systems, the martyr valves are replaced by an orifice plate and the master valve is closed either automatically or manually when the machine is on load. On other systems, steam traps are used in place of the martyr valves, but these are not favoured in high pressure areas.