The boilers (1) are charged continuously with hot steam from the steam network (4) via the boiler feedwater tank (9) and the boiler drums to conserve heat. The condensate arising downstream of tank and drum is passed via expander (14) and condensate tank (19) into the condensate system of the natural-flow steam boiler or turbine and the sampling stations should be held open during this holding period. The natural boiler is shut down and the circuit steam is fed via line (5) to the bottom boiler drum (8) and thence to upper drum (12) to keep the boiler system warm. Pretensioned condensate from drum is bled off the expander at the same time as steam from the auxiliary network is piped over (7) to tank whence condensate is transferred to the expander also and so to the tank and via line (20) into the overall condensate system (21).
