Heating Water Buffer Cylinder/Low Loss Header - Viessmann VITOTRONIC 200 Service Instructions Manual

Heating water buffer cylinder/low loss header

■ With system schemes 3 to 10, the
heating water buffer cylinder is ena-
bled automatically.
■ With system schemes 1 and 2, a heat-
ing water buffer cylinder must be ena-
bled using parameter "Enable buffer
cylinder/ low loss header 7200".
■ For bridging power-OFF periods:
Subject to the electricity tariff, heat
pumps can be switched off at peak
times by the power supply utility. A
heating water buffer cylinder supplies
the heating circuits with heat even dur-
ing this power-OFF period.
■ For hydraulic separation of the volume
flow in the secondary circuit and the
heating circuit. For example, if the
heating circuit flow rate is reduced via
thermostatic valves, the flow rate in the
secondary circuit remains constant.
■ Longer heat pump operating times.
The greater water volume and the pos-
sible separate shutting-off of the heat
source make the provision of an addi-
tional or larger expansion vessel neces-
sary.
Heating
The set buffer temperature depends on
the operating status:
■ "Top"/"Standard"
Maximum value of all set heating cir-
cuit temperatures.
■ "Fixed value"
"Temp. in operating status fixed
value for buffer cyl 7202".
"Operating status", see operat-
ing instructions "Vitotronic 200".
Note
The flow rate of the secondary pump
should be greater than that of the heating
circuit pumps.
Protect the heat pump in accordance
with EN 12828 [or local regulations].
Information about systems with a low
loss header
When using a low loss header, ensure
that the flow rate on the heating circuit
side is greater than the flow rate on the
secondary side of the heat pump.
The heat pump control unit treats a low
loss header like a small heating water
buffer cylinder. Therefore, the low loss
header must be configured as a heating
water buffer cylinder ("Enable buffer
cylinder/ low loss header 7200") in the
heat pump control unit.
The heating water buffer cylinder is
heated if the temperature at the buffer
temperature sensor falls below the set
buffer temperature by more than the
"Hysteresis temperature heating buf-
fer cylinder 7203".
Heating stops if:
■ The set buffer temperature is reached.
■ The "Max. temperature buffer cylin-
der 7204" is reached.
■ Short circuit or lead break of the buffer
temperature sensor.
Function description
25