System Pressure & Temperature - Baxi COMBI 105 HE User Operating Instructions Manual

Fig. 4
Fig. 5
Fig. 6
Fig. 7
Central Heating
Temperature Control
© Baxi Heating UK Ltd 2009
2
1
3
0 4
bar
Normal Pressure
2
1
3
4
0
bar
Requires
Repressurising
2
1
3
4
0
bar
Fault
Domestic Hot Water
Fig. 8
Temperature Control
4.0 System Pressure & Temperature
4.1 Central Heating System Pressure
1. The normal operating water pressure is between 1 and 2.5
bar (Fig. 4). If the pressure exceeds 3 bar the safety pressure
valve will operate and a fault is indicated (Fig. 6). Contact your
installer.
2. It may be necessary to repressurise the system occasionally
(Fig. 5). A filling device (the filling loop) will be fitted on the
system. If you are unsure of its position, or cannot identify it,
consult the installer who fitted the boiler.
3. The filling loop will probably consist of two taps and a
separate metal braided hose with connection fittings.
4. Only when repressurising should the hose be connected
between the two taps. Ensure that the nuts on the pipe ends
are tightened onto the taps.
5. Fully open one of the taps first, and then while watching the
pressure gauge, carefully open the second tap.
6. When the needle on the gauge is indicating 1 or more turn
both taps off.
7. Disconnect the metal braided hose from the taps (a small
amount of water may be present) and remove it. Keep the
hose in a safe place for future use.
4.2 Temperature Control
1. Central Heating: The central heating hot water flow
temperature can be adjusted between 30° C (± 5° C)
minimum and 85° C (± 5° C) maximum.
2. Turn the control knob clockwise to increase the
temperature (Fig. 7). In normal winter usage we recommend
that the central heating temperature be set at maximum.
3. Domestic Hot Water: The temperature of the domestic
hot water can be adjusted by turning the control knob
clockwise to increase up to a maximum of 65° C (Fig. 8).
4. The temperature of the water is also dependent on the
water flow rate and the temperature of the mains coming into
the house.
5. By slightly reducing the flow from the tap the temperature
will increase up to the maximum if required.
6. The flow rate can be reduced down to as low as 2.5
litre/min. The boiler will still recognise the need to heat the
water.
7