Appliance Operation - Baxi Platinum 2 Combi 28 GA Installation & Servicing Instructions Manual

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A
B
Key
1. Pump with Automatic Air Vent
2. Boiler Drain Tap
3. Pressure Gauge
4. Safety Pressure Relief Valve
5. DHW Flow Sensor/Filter/Restrictor*
6. Domestic Hot Water Priority Sensor
7. Domestic Hot Water NTC Sensor
8. Hydraulic Pressure Switch
9. Three Way Valve & Motor
10. Plate Heat Exchanger
11. Gas Valve
12. Safety Thermostat
*On 40kW models the restrictor is in the Cold
Water Inlet connection
Connections:-
A – Condensate Drain
B – Heating Flow
C – Domestic Hot Water Outlet
D – Gas Inlet
E – Cold Water Inlet On/Off Valve and filter
F – Heating Return
© Baxi Heating UK Ltd 2011
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E
C D
13. Heating Flow Sensor
14. Flue Sensor
15. Boiler Adaptor
16. Primary Heat Exchanger
17. Spark Ignition Electrode
18. Burner
19. Flame Sensing Electrode
20. Air/Gas Collector
21. Heating Return Sensor
22. Fan
23. Air/Gas Venturi
24. Expansion Vessel
3.1
1. With a demand for heating, the pump circulates water
through the primary circuit.
2. Once main burner ignites the fan speed 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
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run during this period.
4. When the demand is satisfied the burner is extinguished
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and the pump continues to run for a period of 3 minutes
(Pump Overrun).
3.2
1. Priority is given to the domestic hot water supply. A
demand at a tap or shower will override any central heating
requirement.
2. The flow of water will operate the Hall Effect Sensor
which requests the 3 way valve to change position. This will
allow the pump to circulate the primary water through the
DHW plate heat exchanger.
3. The burner will light automatically and the temperature of
the domestic hot water is controlled by the temperature
1
sensor.
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4. When the domestic hot water demand ceases the burner
will extinguish and the diverter valve will remain in the
domestic hot water mode, unless there is a demand for
central heating.
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4
3.3
F
1. The frost protection mode is integral to the appliance and
Fig. 3
functions as long as there is power and gas supplied to the
boiler. 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. Further protection can be
incorporated by using a system frost thermostat.
3.4
1. The pump will automatically operate for 1 minute in every
24 hours to prevent sticking.

3.0 Appliance Operation

Central Heating Mode
Domestic Hot Water Mode
Frost Protection Mode
Pump Protection
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