31
System version 1
One heating circuit without mixer and
DHW heating (optional solar DHW
heating)
Applications
Heating system with DHW heating
Main components
■ Gas condensing boilers 26 to 60 kW
■ DHW cylinder (dual mode)
■ Solar thermal system
Function description
The boiler circuit
eP
and the DHW cylin-
der
qP
/
qR
are regulated by boiler heat-
ing circuit controller
1
. The heating cir-
cuit and the DHW cylinder are supplied
by their individual circulation pumps
eQ
and
qE
.
Heating mode
The boiler heating circuit controller reg-
ulates the boiler water temperature in
weather-compensated or heat demand-
dependent mode (= flow temperature of
the heating circuit without mixer).
DHW heating without a solar thermal
system
If the temperature falls below the set
DHW temperature selected at control
unit
2
, the burner of boiler
1
starts
and circulation pump
qE
of DHW cylin-
der
qP
or
qR
runs.
Within the periods selected at control
unit
2
, DHW is heated with or without
priority.
DHW heating by the solar thermal
system
Solar circuit pump
wE
starts and DHW
cylinder
qR
is heated up, if the tempera-
ture differential between collector tem-
perature sensor
wQ
and cylinder temper-
ature sensor
qT
exceeds the start tem-
perature differential.
Pump
wE
is stopped according to the fol-
lowing criteria:
■ The actual temperature drops below
the stop temperature differential
■ Exceeding the electronic temperature
limit (up to 90 °C) set in the solar con-
trol module (type SM1)
wZ
■ The temperature selected at high limit
safety cut-out
qZ
(if installed) is
reached
Demands for the auxiliary function are
met by circulation pump
wR
.
Suppression of reheating of the DHW
cylinder by the boiler in conjunction
with solar control module (type SM1)
Reheating suppression takes place in
two stages.
Reheating DHW cylinder
qR
by boiler
1
is suppressed as soon as DHW cyl-
inder
qR
is heated by collectors
wP
. For
this, the set cylinder temperature for
reheating is reduced by boiler
1
. Sup-
pression remains active for a certain time
after solar circuit pump
wE
has been
switched off.
Commissioning, inspection, maintenance
Further details regarding the individual steps
(cont.)
5692 860 GB
Summary of Contents for CU3A
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