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

Boiler Primary Circuit
16
17
13
15
14
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 Temperature Sensor
18 Expansion Vessel
19 Temperature Sensor
20 Secondary Heat Exchanger
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1
2
3 4
6
5
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10
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.
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2. The main burner ignites at low rate, then the gas
valve controls the gas rate to maintain the heating
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temperature measured by the temperature sensor.
3. When the flow temperature exceeds the setting
temperature, a 3 minute delay occurs before the
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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
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isolated. The boiler will not operate.
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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
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thermostat.
Fig. 2
3.3 Pump Protection
1. With the selector switch (see Section 2.1) in the
ON position (
operate for 1 minute in every 24 hours to prevent
sticking.
). If the
) the pump will automatically
Publication No. 5111817