Cooling

 

When the cooling start condition is reached (the boiler sensor temperature has reached 77°), the command to open the water supply valve (relay No. 3) is given, and at the same time a PWM control signal is sent to turn on the pump. For the first ten seconds the pump runs at starting power (40% by default), and then the PWM regulator selects the speed so as to keep the coolant temperature (hereinafter the coolant) at the dephlegmator outlet according to the settings, without dropping below the minimum power (10% by default). As the column warms up and the coolant temperature rises, the pump will increase the flow rate. When boost is finished, the pump again gets starting power for a few seconds to increase the water flow, after which the regulator continues its work.

If a TCA sensor is connected and its temperature is above 39° and above the water temperature, the pump works harder: the regulator treats the water as 3° warmer than the setpoint.

 

Cooling is configured in two places:

 

1. In the configurator on the "Temperatures" («Температуры») and "Pumps" («Насосы») tabs or, when building in the Arduino IDE, in the lines of the sketch:

In the configurator it is "Cooling opening temperature, °C" («Температура открытия охлаждения, °C»). At a boiler temperature of 77°, the command to open the water supply valve is given, a PWM control signal is sent to turn on the pump, and the message "Open the water supply!" («Откройте подачу воды!») is sent to the operator with a sound signal. The message is sent in any case, even if neither a pump nor a valve is used. If a TCA sensor is connected, cooling opens even earlier - when the TCA temperature rises to 70°.

 

//The difference between the set water cooling temperature and the water temperature up to which the pump keeps running after the distillation process is finished in the distillation and rectification modes. The value is in degrees C°, it can be changed.  Turning it off is strongly discouraged.  (for details see here). In the configurator it is "Cooling shutdown temperature margin, °C" («Запас температуры выключения охлаждения, °C»).

 

In the configurator it is "Minimum pump power, %" («Минимальная мощность насоса, %»). As is well known, a motor needs a higher voltage to start than to keep running. This line sets the lowest possible value, in %, at which the motor can keep the water supply pump running without stopping.

 

In the configurator it is "Pump starting power, %" («Стартовая мощность насоса, %»). The value, in % of the rated voltage, at which the pump motor is guaranteed to start.
That is, if your pump (assuming it is already installed in the system and has liquid in it) starts reliably when supplied with 4 volts and does not start with less, then with its rated voltage of 12 volts this is 30% of the rated value. So the value 40 can be replaced with 30.

 

2. In the settings, on the Temperature («Температура») tab - the water sensor setpoint. The pump will hold this temperature during the process.
After heating is turned off, Samovar turns off the pump and closes the water supply valve when one of the conditions is met: the water temperature has dropped 20° below the water sensor setpoint and at least three minutes have passed since heating was turned off, or the boiler, which had been heated above 77°, has cooled below 70°. In Rectification mode with a TCA sensor connected, the TCA must additionally cool to 65°. The message "Close the water supply!" («Закройте подачу воды!») will be sent to the operator.

Samovar 7.00: previously the water was closed only when the water cooled down. In summer, when the inlet water is warm, the pump could run until the operator intervened; now the water is also closed when the boiler cools down.

 

If the water sensor does not respond while heating is on, Samovar performs an emergency heating shutdown.
At a water temperature of 65° and above, Samovar sounds a signal and shows the message "Critical water temperature!" («Критическая температура воды!»); at 70° and above it also reduces the regulator power; at 75° and above it performs an emergency heating shutdown. On an emergency shutdown the valve closes and the pump stops.
If on the Other («Прочие») tab the "Use water flow control" («Использовать контроль потока воды») checkbox is set and a flow sensor is installed, then with cooling on and no flow for 20 seconds, Samovar performs an emergency heating shutdown with the message "Emergency shutdown! Water supply stopped." («Аварийное отключение! Прекращена подача воды.»)

 

In Distillation mode, cooling works the same as in rectification, except that the TCA cooling is not checked when closing.
In Wash Column mode the valve opens the same way, and the pump power is set with the "Pump speed" («Скорость насоса») slider on the BK page or automatically from the steam temperature setpoint in the program line, see Wash Column.
In NBK mode cooling opens only while heating is on; it closes, as in rectification, when the water has cooled below the water sensor setpoint by DELTA_T_CLOSE_VALVE (20°) or the boiler has cooled.
In Beer mode the valve and pump turn on at the "Cooling" («Охлаждение») program line and, when the wort needs to be cooled, at the "Fermentation" («Брожение») line; the pump then runs at full power. The same pump output turns on the wort transfer pump at the lines where this is set in the mashing program.
In Cheesemaking mode the valve and pump are used at the cooling stages, see Cheesemaking Mode.
In Sous-vide mode cooling is not used.

 

For the implementation, see the assembly guide.