Buderus Logamax plus GB162-100 User Manual page 14

5 Commissioning the heating system
 Open the heating flow and return valves on the pump
group (fig. 12) (open position: parallel to the pipe).
 Read the pressure from the pressure gauge on the
pump group or on the control panel of the BC10
(fig. 13).
The pressure in the heating system, which is measured
directly at the boiler, must be at least equal to the
required pre-pressure of the expansion vessel plus
0.5 bar. The minimum pressure must not be less than
1.0 bar (if the heating system is cold). The maximum
pressure in the heating system, measured directly at the
boiler must not exceed 2.5 bar.
 Close the water tap and drain cock.
It is very important that the heating system
is now purged, since all air will collect at the
highest point of the heating system when
the system is slowly filled with water.
 Purge the heating system via the air vents/valves on
the radiators. Start at the lower floor of the premises
and then work your way up from floor to floor (fig. 14).
If the boiler has been in use for approx. one week and
the pressure reading on the display is less than 1.0 bar,
the system has to be topped up.
The pressure loss in a heating system is caused by air
bubbles escaping via fittings and (automatic) air vents.
The oxygen contained in the fresh heating water will also
escape from the heating water after some time and
cause the pressure in the heating system to become
lower.
This explains why it is normal that the heating system
has to be topped up a couple of times after commission-
ing it.
Eventually the system will have to be topped up on aver-
age once a year.
Should it be necessary to top up the heating system
more frequently, water is probably escaping due to a
leakage in the system or a defective expansion vessel.
In this case the cause of the water loss must be repaired
as soon as possible.
14 Logamax plus GB162-65/80/100 - Subject to modifications resulting from technical improvements!
fig. 12 Opening the flow and return valves (here: open
position)
fig. 13 Reading the pressure gauge
fig. 14 Purging the radiators
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