4.3 Hydraulic Connection; General Information - Viessmann VITODENS 200-W Technical Manual

Design information
IP rating
Protection class

4.3 Hydraulic connection

General information

System design
Viessmann condensing boilers can generally be installed in any fully
pumped hot water heating system (sealed unvented system).
Connection sets with an integral circulation pump are available as
accessories.
Minimum system pressure 1.0 bar.
The boiler water temperature is limited to 82 ºC.
To keep distribution losses as low as possible, we recommend sizing
the heat distribution system for a maximum flow temperature of
70 ºC.
Chemical anti-corrosion agents
Corrosion is generally avoided in correctly installed and operated
sealed unvented 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
4
via single-walled heat exchangers (instantaneous water heater or
DHW cylinder).
For this, observe the VDI Directive 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.
Even with condensing boilers, connect underfloor heating systems and
heating circuits with a very large water content (>15 l/kW) to the boiler
via a 3-way mixer; see technical guide "Control of underfloor heating
systems" or the relevant sample applications.
Install a temperature limiter in the flow of the underfloor heating circuit
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).
Route the discharge pipe in accordance with EN 12828 into a drain
outlet (drain outlet kit available as an accessory). The drain outlet
incorporates a siphon as a stench trap.
Low water indicator
According to EN 12828, a low water indicator can be omitted for boilers
up to 300 kW, as long as heating can be reliably prevented in the case
of water shortage.
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.
VIESMANN
36
(cont.)
IP 44
F
Permissible medium temperature
Max. head
Max. capacity
Zero volt contact
Attic heating centre
The installation of a low water indicator specified as compulsory to EN
12828 is not required when installing the Vitodens in an attic heating
centre.
The Vitodens condensing boilers are protected against water shortage
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 water quality.
■ Fill and top-up water with a water hardness in excess of the following
values must be softened, e.g. with the small softening system for
heating water (see the Viessmann Vitoset pricelist):
Total permissible hardness of the fill and top-up water
Total heating Specific system volume
output
kW < 20 l/kW
≤ 50 ≤ 3.0 mol/m
3
(16.8 °dH)
> 50 to ≤ 200
≤ 2.0 mol/m
3
(11.2 °dH)
≤ 1.5 mol/m
> 200 to
3
≤ 600
(8.4 °dH)
> 600 3
< 0.02 mol/m
(0.11 °dH)
■ For systems with a specific system volume in excess of 20 litres/kW
heating output, use the output of the smallest boiler in multi boiler
systems.
■ An antifreeze additive suitable for heating systems can be added to
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 resulting from these cau-
ses.
When engineering the system, observe the following:
■ Install shut-off valves in different sections. This prevents the need
for draining all the heating water in the case of repairs or system
expansion.
■ In systems > 50 kW, install a water meter to record the volume of
the fill and top-up water. Record the amount of water filled into the
system and the water hardness.
Operating information:
■ Commission the system step by step, starting with the lowest boiler
output and a high heating water flow rate. This prevents a localised
concentration of limescale deposits on the boiler heating surfaces.
■ In multi boiler systems, start all boilers simultaneously to prevent the
entire limescale deposit settling in the heat transfer area of just one
boiler.
■ During expansion or repair work, only drain the necessary pipework
sections.
+60 °C
45 kPa
450 l/h
N/C, breaking capacity
230 VA
≥ 20 l/kW to ≥ 50 l/kW
< 50 l/kW
≤ 2.0 mol/m
3 < 0.02 mol/m 3
(11.2 °dH) (0.11 °dH)
≤ 1.5 mol/m
3 3
< 0.02 mol/m
(8.4 °dH) (0.11 °dH)
≤ 0.02 mol/m
3 < 0.02 mol/m 3
(0.11 °dH) (0.11 °dH)
3 3
< 0.02 mol/m < 0.02 mol/m
(0.11 °dH) (0.11 °dH)
VITODENS 200-W