Baxi Potterton BAXI COMBI INSTANT 105E - Manual (Page 8)

3.0 Operating the Boiler
8
3.9 Central Heating System Pressure
1. The water pressure in the central heating
system is indicated by the pressure gauge.
2. With the system cold and the boiler not
operating the pressure should be between 0.5
and 1.0 bar. During operation the pressure
should not exceed 2.5 bar, and will normally be
between 1.0 and 2.0 (Figs. 18 & 19).
3. A pressure of 3 or greater indicates a fault.
The safety pressure relief valve will operate, at a
pressure of 3 (Fig. 20). It is important that your
Service Engineer is contacted as soon as
possible.
4. The MINIMUM pressure for correct operation
is 0.5. If the pressure falls below 0.5, this may
indicate a leak on the central heating system
(Fig. 21).
5. The system must be re-pressurised by your
Service Engineer.
3.10 To Shut Off the Boiler
1. For short periods: Turn the selector switch to
the OFF position (Fig. 22).
2. For long periods: Turn off the selector switch
(Fig. 22), electricity and gas supplies.
If your home is to be left unoccupied for long
periods during cold weather the boiler and
whole system should be drained unless there
is additional frost protection.
3. Your installer will advise you about frost
protection and draining the system.
IMPORTANT: When the selector switch is in
the ‘0’ (Off) position the electrical supply to the
boiler is isolated. The boiler will not operate
and the integral timer (if fitted) will require
resetting once the selector switch is set to
either Position (i) or Position (ii).
3.11 Frost Protection Mode
1. The frost protection feature will operate when
the selector switch is in the central heating and
domestic hot water mode.
The gas and electrical supplies to the boiler must
be on and the system pressure must be within
the range described in Section 3.9.
2. If the system temperature falls below 5°C, then
the boiler will fire until the water temperature has
been raised.
3. Further frost protection can be incorporated by
using a frost thermostat to protect the whole
system.
2
1
0 4
3
bar
2
1
0 4
3
bar
2
1
0 4
3
bar
2
1
0 4
3
bar
ON/OFF
Selector Switch
OFF Position
Fig. 22
Normal Pressure (when cold)
Normal Pressure (operating)
Fig. 18
Fault
Fig. 19
Below Minimum
Fig. 20
Fig. 21
Pressure Gauge