Operation manual for M RS 420 ESTYMA control unit
14
NOTE !!!
If the boiler temperature for hot tap water is lower than the
temperature in the manual or weather-compensated mode, the boiler will operate
at the higher of the two temperature settings.
CONTROL OF THE FOUR-WAY MIXING VALVE
The controller controls the four-way mixing valve. The purpose is to maintain the
set temperature of the heating medium in the central heating circuit. The
controller also protects the boiler against excessively low temperature of the
heating medium returning from the heating circuit. Protection of the boiler has
priority over control of the temperature in the central heating circuit. When the
temperature of the heating medium returning from the installation is too low, the
valve is turned down. When the minimum temperature of the returning medium is
exceeded, the element responsible for maintaining the required temperature
downstream from the mixer takes over control. The temperatures are set in the
HEATING submenu.
The central heating temperature setting is
calculated by the controller when the boiler
operates in the weather-compensated or manual
mode. The temperature setting downstream from
the mixer depends on the status of the room
regulator:
- closed contacts
(heating required) – the
temperature is determined from the heating curve.
- open contacts
(heating not required) – the temperature downstream from the
mixer is lower by the value of the parameter “reduction” in the “HEATING”
submenu.
The parameter “temp.calculat” shows the current calculated value of the
temperature setting of the central heating circuit.
“SERVICE MODE” parameters affecting mixer actuator control:
“Tmax.heating” - is the upper limit of the temperature of the heating medium
downstream from the central heating mixer.
Figure 6: HEATING submenu
