System Example 1 - Viessmann SM1 Installation And Service Instructions Manual

System example 1

DHW heating with dual mode DHW cylinder
Function description
DHW heating with solar energy
If the temperature differential between
collector temperature sensor eQ and cyl-
inder temperature sensor qQ is greater
than the start temperature differential
(coding address 00), solar circuit pump
eE is started and DHW cylinder qP is
heated.
Solar circuit pump eE stops if:
■ Actual temperature drops below stop
temperature differential (coding
address 01)
■ Maximum cylinder temperature is
exceeded (coding address 08)
■ The temperature selected at high limit
safety cut-out qW (if installed) is
reached
Additional function for DHW heating
The requirements for the additional func-
tion are achieved through circulation
pump qT.
Suppression of DHW cylinder reheat-
ing by the boiler
Reheating suppression takes place in
two stages.
Required codes at the oil/gas boiler control unit
Boiler installation and service
instructions
Installation sequence
Reheating of DHW cylinder qP by boiler
1 is suppressed as soon as DHW cyl-
inder qP is heated by collectors eP. For
this, the set cylinder temperature for
reheating is reduced by boiler 1. After
solar circuit pump eE has been switched
off, suppression remains active for a cer-
tain time.
In the case of uninterrupted heating by
the collectors eP (> 2 h), boiler 1 will
only reheat if the set DHW temperature
selected at boiler control unit 2 (coding
address "67") is not achieved.
A third set DHW temperature can be
specified via coding address "67" (set-
ting range 10 to 95 °C). This value must
be below the first set DHW tempera-
ture.
DHW cylinder qP will only be heated by
boiler 1 if this set value cannot be ach-
ieved by the solar thermal system.
DHW heating without solar energy
The upper section of DHW cylinder qP is
heated by boiler 1. The cylinder ther-
mostat with cylinder temperature sen-
sor qZ of boiler control unit 2 regulates
cylinder heating.
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