Heating Circuits/Cooling Circuit - Viessmann VITOTRONIC 200 Service Instructions Manual

Function description
Heating water buffer cylinder/low loss header
Switching a heating water buffer cylinder on and off
Operating status
■ Buffer temperature sensor
■ Return temperature sensor,
secondary circuit
Frost protection
If the temperature at the buffer tempera-
ture sensor drops below 3 °C, the heat
pump control unit also immediately
switches on the instantaneous heating
water heater and the external heat
source.
Note
Any block of the instantaneous heating
water heater for the central heating
becomes ineffective ("Enable instant.
heating water heater for central heat-
ing 7902" set to "0").

Heating circuits/cooling circuit

Instructions for minimum flow rate
Heat pumps require a minimum flow rate
of heating water that must be main-
tained.
Note
Brine/water heat pumps also require a
minimum flow rate on the primary side.
Minimum flow rates
Installation and service instruc-
tions of the relevant heat pump.
Depending which sensor has reached the set buffer temperature first.
*1
26
"Top" "Standard"
*1 ON
ON and OFF
OFF
OFF *1
Frost protection heating ends when the
temperature inside the heating water
buffer cylinder rises above 10 °C.
Systems with small water volumes
For systems with small water volumes
(e.g. heating systems with radiators),
use a heating water buffer cylinder to
prevent excessive heat pump cycling
(starting/stopping).
(cont.)
"Fixed value"
ON
OFF