Water Level Indicator; Flow Meter (Turbine); Hws Valve (Steam Operation) - Saeco Classic Service Manual

ROYAL 4. FUNCTION/TIMING

4.3. Water level indicator

The water level in the water tank is monitored by a float fitted with a magnet core. If the water level is too
low, the magnet is no longer within the range of the reed contact, which transmits the low water level signal
to the CPU.

4.4. Flow meter (Turbine)

The machine is also equipped with a flow rate monitoring system. The system checks whether the water
monitoring flow meter (turbine) turns. If no pulses are generated from the flow meter within 10 seconds, the
current cycle is interrupted. The fault is indicated by the water low indicator (machine without float) or by
the de-aerate indicator in machines with float (reed sensor). If this control mechanism is activated, the
machine must be de-aerated. During these signals, the pump operates at maximum output. As soon as the
pump has created sufficient flow, the pump output is reduced to approx. 20 l/hr.
The water quantity is generally controlled according to the coffee quantity programmed through the flow
meter (turbine) pulses.

4.5. HWS valve (steam operation)

The HWS valve is required for water and steam dispensing, as well as during de-aeration.
If the hot water valve is opened during brewing, the coffee flow is interrupted and the Water Low indicator
begins to flash or the message Close Dial appear on the display. As soon as the hot water valve is closed, the
brewing process will continue (only in machines without Instant Steam).
The operating temperature during steam dispensing is approx. 125°C. The steam button is pressed to activate
steam production (in machines without Rapid or Instant Steam). Steam dispensing occurs via the HWS
valve.
In machines with Rapid Steam, the steam can be dispensed immediately after the end of the coffee cycle
(second instantaneous water heater).
In machines with Instant Steam, the steam or cappuccino can be dispensed even during the coffee cycle.
The pump pulses the steam dispensed. This means that constant steam dispensing is ensured over a long
period of time. The flow rate of the pump is adjusted on the basis of the thermoblock temperature. If the
temperature is too low, the pump pulses are slowed down. This may occur, for instance, when the hot water
valve opens before the temperature indicator lights up.
In machines with Instant Steam, the steam is added during hot water dispensing in order to reach an even
higher water temperature. The flow volume can be adjusted under the items HOT WATER or
TURBOWATER (when System 2 is turned on).
Once the steam has been dispensed, the steam valve closes and the steam button must be pressed for normal
operating mode. The steam and coffee temperature indicators flash or the message OVERHEATING
appears in machines with digital display, until the machine has cooled and the machine cannot dispense
coffee. Cooling can be achieved by dispensing hot water. The pump functions at maximum output and the
heating remains turned off as long as the temperature indicator flashes (R. Classic) / Overheating signal
remains on (Royal Digital/Exclusive). These measures ensure that the cooling process is accelerated and the
overheating signal will disappear after a few seconds (only in machines without Instant or Rapid Steam).
Saeco International Group REV.4 SEPT.2003 Page 21/22