Appliance Operation - Potterton Performa System 12 HE Installation & Service Instructions Manual

3.0

APPLIANCE OPERATION

3.1 Operating Mode (Fig. 2)
1. With a demand for heating, the pump circulates
water through the primary circuit. At a pre-determined
flow rate the hydraulic differential pressure switch
operates, initiating the ignition sequence.
2. The main burner ignites at low rate, then the gas
valve controls the gas rate to maintain the heating
temperature measured by the temperature sensor.
3. 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.
4. When the demand is satisfied the burner is
extinguished and the pump continues to run for a
period of 3 minutes (Pump Overrun).
IMPORTANT: When the selector switch is in the
'0' (Off) position the electrical supply to the boiler is
isolated. The boiler will not operate.
3.2 Frost Protection Mode
1. The frost protection mode is integral to the
appliance and functions when the selector switch (see
Section 2.1) is in the ON position (
system temperature falls below 5° C then the boiler
will fire on its minimum setting until a flow
temperature of 30° C is reached. Further protection
can be incorporated by using a system frost
thermostat.
3.3 Pump Protection
1. With the selector switch (see Section 2.1) in the
ON position ( ) the pump will automatically
operate for 1 minute in every 24 hours to prevent
sticking.
Publication No. 5111817
Boiler Primary Circuit
15
). If the
11
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 Hydraulic Differential Pressure Sensor
16 Safety Thermostat
17 Central Heating Temperature Sensor
18 Expansion Vessel
19 Water Heating Sensor
20 Secondary Heat Exchanger
5
16
17
13
14
10
1
19
2
3 4
6
18
8
9
12
Fig. 2
20
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