Honeywell SDC Service Manual page 196

Hydraulic Components
Switching times
NOTE
Circulation pump with
district heating
7.3.5.2.1
Function
196
With an standstill time of 15 min. and a period of 20 min., the
circulation pump will run for 5 min. before the subsequent pause
of 15 min.
The following is used to calculate the switching-on degree:
n = 5/20 = 25%
In this function a hot-water circulation pump can be coupled to an
existing automatic program of a control circuit with regard to the
switch-on and switch-off times. The hot-water circulation pump is
in operation during the heating or hot-water cycles of the selected
circuit and program.
If operation of the time programs P2 and P3 were not enabled
(see "System Parameters" menu, time program parameter) and
the circulation pump is assigned to one of these programs, the
pump will operate according to the stored default times. The same
applies if a switching-time program was selected that does not
exist for the controller type in use (e.g. an MC2 for SDC 9-21).
Hot-water parameter 16 allows switching off of the circulation
pump during hot-water loading.
Electrical heating element (ELH)
The electrical heating element (ELH) provides 2 different
functions depending on the parameter settings.
1. Adjustment: in „Hydraulic" menu, parameter 5,6 or 7, setting 5
= electrical heating element
The ELH controls (via circuit breaker) an electrical heating
element in the water heater as long as the automatic summer
switch-off is active. Switch-off of the electrical heating element
occurs via an additional hot-water circuit thermostat to be created
with the corresponding safety equipment.
This application is ueful, if for example heating is completely
turned off during summer operation and the process water should
be heated with the means of the ELH.
2. Adjustment: in „Hydraulic" menu, parameter 5,6 or 7, variable
output = 47 Electrical water heater, and in „Hot Water" menu,
parameter 28 = switch-on delay electrical water heater and
Parameter 29 = Offset Electrical water heater.
SDC / DHC
EN2H-0221GE51 R0812