Honeywell SDC Service Manual page 204

Hydraulic Components
204
Heating circuit controls send their demand value to buffer control.
Hot-water and buffer controls demand energy from the heat
generator when required.
With hot-water priority activated, this function acts on the buffer
loading pump and not on the heating circuits.
See the table below for detailed correlations.
Control mode 3 – Discharge control for heating circuit and hot-
water demand
System hydraulics
a Buffer tank
b Heat generator
Heating circuit and hot-water controls send their demand value to
buffer control. The buffer loading pump output switches ON when
the energy demand can be met by the buffer. If the energy in the
buffer is insufficient, buffer control demands additional energy
from the heat generator and the buffer loading pump switches
OFF.
If there is no demand for the heating circuits and hot-water
loading, the buffer loading pump switches off.
See the table below for detailed correlations.
c Hot-water tank
EN2H-0221GE51 R0812
SDC / DHC