Baxi Megaflo System HE IE Series Installation & Servicing Instructions Manual page 7

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Fig. 2
Key
1 Heat Exchanger
2 Burner
3 Ignition Electrode
4 Flame Sensing Electrode
5 Gas Valve
6 Pump
7 Automatic Air Vent
8 Pressure Relief Valve
9 Boiler Drain Point
10 Gas Inlet
11 Boiler Flow
12 Boiler Return
13 Pressure Gauge
14 Automatic By-Pass
15 Water Pressure Sensor
16 Safety Thermostat
17 Temperature Sensor
18 Expansion Vessel
19 Return Temperature Sensor
20 Fan
1. With a demand for heating or hot water, the pump circulates water through the primary circuit. If the pressure is at least 0.2 bar the ignition
sequence will start.
2. When the flow temperature exceeds the setting temperature, a 3 minute delay occurs before the burner relights automatically (anti-cycling).
The pump continues to run during this period.
3. When the demand is satisfied the burner is extinguished and the pump continues to run for a period of 3 minutes (Pump Overrun).