Honeywell SDC Service Manual page 167

SDC / DHC Hydraulic Components
If another controller (addr. 20 ... 50) is connected to the direct
heating circuit pump while the screed function is active, the
screed function is cancelled automatically for the direct heating
circuit pump.
All other heating circuits except for the direct heating circuit at
addr. 10 are disabled. Frost protection monitoring, for example,
does not occur for these heating circuits during this time.
Function The screed function is used exclusively for the required drying of
newly applied screed on floor heating systems. The process is
based on recommendations of the German Bundesverbandes
Flächenheizungen (Federal Association for Surface Heating)
concerning the heating of fresh floor covers (heating according to
a mandatory temperature profile).
This is a special function that is not interrupted by any other
control mode (including manual operation or emission
measurement.
The screed function can be activated for mixed heating circuits
and, in special cases (e.g. in conjunction with a condensing
boiler) also for a direct heating circuit.
When the screed function is active, all weather-dependent control
functions of the heating circuit concerned are switched off. The
respective heating circuit operates independent of the control
mode (switching times) as a constant temperature controller.
An active screed function can be deactivated at any time
(parameter screed function = OFF).
On completion of the screed function, the heating circuit returns to
operation according the current control mode setting.
The screed function consists of two steps:
EN2H-0221GE51 R0812 167