Supplied By www.heating spares.co Tel. 0161 620 6677
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1.5
INTERNAL VIEW
KEY
1 Control panel
2 Ignition transformer
3 Combustion chamber
4 Fan
5 Combustion analysis intakes
6 Negative pressure intake
7 Positive pressure intake
8 Air pressure switch
9 C.H. sensor (SM)
10 Main exchanger
11 100°C safety stat
12 Gas valve
13 Flow water switch
14 Divertor valve
19 C.H. water filter
Fig. 3
1.6
BOILER OPERATION
The boiler operating mode is controlled by the selector switch
on the control panel. When set to winter (
) it will operate in
the Domestic Hot Water and Central Heating modes. For
Domestic Hot Water only the selector switch should be set to
summer (
).
Domestic hot water supply always takes priority over central
heating. If a demand for hot water is required during a central
heating period, the boiler will automatically switch to hot water
mode until the demand is satisfied.
1.6.1
Central Heating mode
If there is a call for central heating the pump will start to circu-
late the primary heating water and the fan will run at full speed;
once the air pressure switch has been proved the burner will
light. The burner output then automatically adjusts to suit the
system demand; as the temperature of the heating water in the
boiler approaches that set by the adjustable central heating
control knob the burner output is reduced. When this set tem-
perature is reached, the burner extinguishes and the fan stops.
The pump continues to run for 30 seconds to prevent residual
heat build up in the boiler. The burner will not relight for 3 min-
utes unless there is a demand for domestic hot water during
this period.
1.6.2
Domestic hot water mode
When there is a demand for hot water, the diverter valve oper-
ates and the pump circulates the primary heating water. The
fan will run at full speed; once the air pressure switch has been
proved the burner will light.
The burner output then automatically adjusts to suit the
demand required to raise the temperature set by the
adjustable domestic hot water control knob. When the hot
water demand has been satisfied, the diverter valve operates
to divert the primary heating water to the central heating, if the
selector is set to winter (
) and there is a C.H. demand, oth-
erwise the burner will extinguish.
