Baxi Potterton 24 Eco HE manual Appliance Operation, Central Heating Mode Fig

3.0APPLIANCE OPERATION

NOTE: All delay timers mentioned in 3.1 and 3.2 are overridden by domestic hot water demand.

3.1Central Heating Mode (Fig. 4)

1.With a demand for heating, the pump circulates water through the primary circuit. At a pre- determined flow rate the central heating flow 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.

3.2Domestic Hot Water Mode (Fig. 5)

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 DHW flow switch which causes 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 sensor.

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.

IMPORTANT: When the selector switch is in the ‘0’ (Off) position the electrical supply to the boiler is isolated. The boiler will not operate and the integral timer (if fitted) will require resetting once the selector switch is turned to either the DHW or CH position.

Central Heating Circuit								1
									27
								2
							3	4	7
				26
							5		6
		25							8
		24
		23						9
		22							11
		21			17
									10
		20		18
	Fig. 4	16	19		15	14		13	12
Key
1	Primary Heat Exchanger					14	Gas Inlet
2	Burner					15	Domestic Hot Water Outlet
3	Ignition Electrode					16	Heating Flow
4	Flame Sensing Electrode					17	Pressure Gauge
5	Gas Valve					18	Hydraulic Differential Pressure Sensor Microswitch
6	Pump					19	Automatic By-Pass
7	Automatic Air Vent					20	Hydraulic Differential Pressure Sensor
8	Plate Heat Exchanger					21	Diverter Valve Assembly
9	Flow Sensor with Filter					22	Domestic Hot Water Flow Priority Assembly
10	Pressure Relief Valve					23	Domestic Hot Water Flow Priority Microswitch
11	Boiler Drain Point					24	Temperature Sensor
12	Heating Return					25	Overheat Thermostat
13	Cold Water Inlet On/Off Valve and Filter					26	Expansion Vessel
						27	Secondary Heat Exchanger
								1

Domestic Hot Water Circuit

27

2

3 4

7

26

56

25

		24				8
	23				9
	22					11
	21		17
						10
		20
Fig. 5	16	18	15	14	13	12
		19

Publication No. 5111811 7