4.3 Hydraulic Connection; General; Expansion Vessels; Low Loss Header - Viessmann VITODENS 200-W Technical Manual

Design information
(cont.)
IP rating
Protection class

4.3 Hydraulic connection

General

System design
Viessmann condensing boilers can generally be installed in any pum-
ped hot water heating system (sealed system).
Connection sets with integral circulation pump are available as acces-
sories.
Minimum system pressure 1.0 bar.
The boiler water temperature is limited to 82 ºC.
To minimise distribution losses, we recommend that you size the heat
distribution system to a max. flow temperature of 70 ºC.
Chemical anti-corrosion agents
Corrosion is generally avoided in correctly installed and operated
sealed heating systems.
Never use chemical anti-corrosion agents.
Some manufacturers of plastic pipes recommend the use of chemical
additives. In such cases, only use anti-corrosion agents offered by the
heating trade that have been approved for boilers with DHW heating
via single-walled heat exchangers (instantaneous water heater or
DHW cylinder).
For this, observe the VDI guideline 2035 [or local regulations].
Heating circuits
For heating systems with plastic pipes, we recommend the use of
impermeable pipes to prevent the diffusion of oxygen through the pipe
walls.
Provide system separation in heating systems with plastic pipes to DIN
4726 that are permeable to oxygen. We supply a separate heat
exchanger for this.
Install a sludge separator in underfloor heating systems and systems
with a large water content; see the Viessmann Vitoset pricelist.
Connect underfloor heating systems with very large water content
(>15 l/kW), even with condensing boilers, to heating circuits via a 3-
way mixer; see technical guide "Control of underfloor heating sys-
tems" or the relevant sample applications.
Install a temperature limiter into the flow of the underfloor heating cir-
cuit to limit the maximum temperature. Observe the requirements of
DIN 18560-2 [or local regulations].
Plastic pipework for radiators
We also recommend the installation of a temperature limiter to restrict
the maximum temperature of plastic pipes in heating circuits with radi-
ators.
Safety valve
A safety valve in accordance with TRD 721 is part of the heating circuit
connection set (accessory) (opening pressure 4 bar).

Expansion vessels

In accordance with EN 12828, water heating systems must be equip-
ped with an expansion vessel.

Low loss header

Application
Design rules for system hydraulics:
VITODENS 200-W
IP 44 Permissible medium temperature
F Max. head
Max. capacity
Zero volt contact
Route the blow-off line in accordance with EN 12828 into a drain outlet
(drain outlet kit available as an accessory). The drain outlet incorpo-
rates a siphon as a stench trap.
Low water indicator
According to EN 12828, a low water level indicator can be omitted for
boilers up to 300 kW, as long as heating can be reliably prevented
when the water level is too low.
Viessmann Vitodens boilers are equipped with a low water indicator
(boil-dry protection). Tests have verified that the burner will be auto-
matically switched OFF in the event of water shortage due to a leak in
the heating system and simultaneous burner operation, before the
boiler or the flue system reach unacceptably high temperatures.
Attic heating centre
The installation of a low water indicator specified as compulsory by
DVGW is not required when installing the Vitodens in an attic.
The Vitodens condensing boilers are protected against low water lev-
els in accordance with EN 12828.
Water quality/Frost protection
Unsuitable fill and top-up water increases the level of deposits and
corrosion and may lead to boiler damage.
Regarding the quality and volume of heating water, incl. fill and top-up
water, observe VDI 2035.
■ Thoroughly flush the entire heating system prior to filling it with water.
■ Only use fill water of potable quality.
■ Fill water with a water hardness in excess of the following values
■ An antifreeze additive suitable for heating systems can be added to
■ For commissioning or systems with a volume that is in excess of
Installation examples
For installation examples for the Vitodens 200-W, see "System exam-
ples".
The size of the expansion vessel is subject to the heating system
specification and should be checked in each case.
must be softened, e.g. with the small softening system for heating
water (see the Viessmann Vitoset pricelist):
– Vitodens up to 45 kW: 16.8 °dH (3.0 mol/m
– Vitodens from 60 kW and multi-boiler systems up to 200 kW:
3
11.2 °dH (2.0 mol/m )
– Multi-boiler systems above 200 kW: 8.4 °dH (1.5 mol/m
the fill water. The antifreeze manufacturer must verify its suitability,
since otherwise damage to gaskets and diaphragms can occur as
well as noise during heating operation. Viessmann accepts no lia-
bility for damage or consequential damage as a result.
20 litres/kW, observe VDI 2035.
+60 °C
45 kPa
450 l/h
N/C, breaking capacity
230 VA
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VIESMANN
35
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