Checking The Function Of Safety Equipment - Viessmann Vitoplex 200 SX2A Service Instructions For Contractors

Commissioning, inspection, maintenance
Checking connections and sensor well on the heating water side for tight-
ness

Checking the function of safety equipment

Check safety valves, water level and pressure limiter in
accordance with manufacturer's instructions.
Checking the function of the pressure switch
Installation instructions, pressure switch set
Checking the expansion vessel and system pressure
Expansion vessel manufacturer's instructions
Expansion vessel
1. Drain the system until the pressure gauge indi-
cates "0" or close the cap valve on the expansion
vessel and reduce the pressure in the expansion
vessel.
Note
The pre-charge pressure of the expansion vessel
(p ) is made up of the static system pressure (p
0
(= static head) and a supplement (p
plement).
The supplement depends on the high limit safety
cut-out setting.
■ 100 °C: Supplement 0.2 bar (0.02 MPa)
■ 110 °C: Supplement 0.7 bar (0.07 MPa)
Pump controlled pressure maintaining systems
!
Please note
Pressure fluctuations may cause damage to the
boiler or to other system components.
In heating systems with automatic pressure
maintaining systems, and in particular pump
controlled systems with integral deaeration, we
recommend the installation of a diaphragm
expansion vessel for individual boiler protection.
This reduces the frequency and level of pres-
sure fluctuations. This contributes considerably
to improved operational reliability and a longer
service life of the system components.
Boiler out- kW
put
Expansion litres
vessel
For water quality requirements, see page 22.
*1
12
St
= p + sup-
0 St
Up to Up to Up to
300 500 1000
50 80 140
Note
Carry out this test on a cold system.
2. If the pre-charge pressure of the expansion vessel
is lower than the static system pressure, top up
with nitrogen until the pre-charge pressure is 0.1 to
0.2 bar (0.01 to 0.02 MPa) higher.
The static pressure corresponds to the static head.
3. Top up with softened water
) sure of the cooled system is 0.1 to 0.2 bar (0.01 to
0.02 MPa) higher than the pre-charge pressure of
the expansion vessel.
Permiss. operating pressure: 4 bar (0.4 MPa)
!
Please note
The ingress of oxygen can result in system dam-
age as a consequence of oxygen corrosion.
Only use pump controlled pressure maintaining
systems that are sealed against corrosion. The
pressure maintaining systems must be protected
against oxygen ingress into the heating water.
Pump controlled pressure maintaining systems
with atmospheric deaeration through cyclical
pressure release bring about central post-venti-
lation of the heating system. They do not pro-
vide oxygen removal in the sense of corrosion
protection as described in VDI 2035 Part 2.
until the charge pres-
*1