Shutting Down Heat Pumps - Viessmann VITOTRONIC 200 Service Instructions Manual

Function description
Heat pump cascade

Shutting down heat pumps

Lag heat pumps and/or compressors are shut down
when the different stages of the output integral I
times "Start threshold 730E") are undershot, in
reverse order to the starting sequence.
External functions
The following functions are available:
External demand/external mixer OPEN or control
■
function
■ External changeover of operating status
■ External blocking/external mixer CLOSE or control
function
Overview of external functions
Connection
External demand
"External demand" signal:
X3.12/X3.13 on the cross connect PCB: See page 289.
■
or
X3.12/X3.13 on the luster terminals: See from page 292.
■
or
Via KM-BUS by the following devices:
■
–
EA1 extension (input DE3)
– Vitocom
Signal effects
External demand
Switch on compressor.
■
OPEN heating circuit mixer or con-
■
trol mode
Regulate flow temperature in sec-
■
ondary circuit to a specified set flow
temperature: See below.
32
/
(cont.)
(n-
L
Operating status changeover
Operating status changeover
Change the operating status of the
following system components for a
specific duration:
Heating circuits
■
Buffer cylinder
■
DHW cylinder
■
Mechanical ventilation with con-
■
nected ventilation unit
If the return temperature in the secondary circuit
exceeds the set value by the stop hysteresis, the lead
heat pump as well as all lag heat pumps are immedi-
ately stopped, irrespective of output integral I
Note
The external functions are not possible in conjunction
with the following functions:
■ Smart Grid
■ External hook-up for heating/cooling circuits
■ / : Cooling with heating water/coolant buffer
cylinder
External blocking
"External blocking" signal:
X3.2/X3.14 on the luster termi-
■
nals: See page 292.
or
Via KM-BUS by the following devi-
■
ces:
–
EA1 extension (input DE2)
– Vitocom
Note
The "External blocking" signal takes
priority over the "External demand"
signal.
External blocking
Switch off compressor.
■
CLOSE heating circuit mixer or
■
control mode
.
L