Baxi 35/80 IE, Installation & Servicing Instructions Manual

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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
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 only with the selector
switch (see
Section 2.1 ) in the domestic hot water and central heating position. If the system
temperature falls below 5°C then the boiler will fire on its minimum setting until a flow
temperature of 30°C is reached. This will only protect the boiler, not the complete system.
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 either the central heating or central heating
and hot water position the pump will automatically operate for 1 minute in every 24 hours to
prevent sticking.
Page 6
4.0 Technical Data
4.1 System 35/80 IE
Appliance Type C
12
C
32
Appliance Category CATⅡ
2H 3+
Heat Input (Gross)
Max Min