Operating instructions

Filling the heating system

Please note

Unsuitable fill water increases the level of deposits and corrosion and

may lead to boiler damage.

Thoroughly flush the entire heating system prior to filling it with water.

Only use fill water of potable quality.

Soften fill water with hardness exceeding 3.0 mol/m

, e.g. using a

small softening system for heating water (see Viessmann Vitoset price

list).

An antifreeze additive suitable for heating systems can be mixed with

the fill water. The antifreeze manufacturer must verify its suitability.

1. Check the inlet pressure of the dia-

phragm expansion vessel.

2. Close the gas shut-off valve.

3. Fill the heating system via the boil-

er fill & drain valve A in the heat-

ing return (at the connection set or

on site). (Minimum system pres-

sure > 1.0 bar).

Note

If the control unit has not been

switched ON prior to filling the sys-

tem, then the servomotor of the

diverter valve will still be in its cen-

tral position, and the system will be

completely filled.

4. If the control unit had already been

switched ON before filling began:

Switch ON the control unit and acti-

vate the fill program via coding

address "2F:2".

5. Close boiler fill & drain valve A.

6. Close the shut-off valves on the

heating water side.

Further details regarding the individual steps

Commissioning, inspection, maintenance

5692 672 GB