Bosch Appliances 28i junior Ignition Sequence, Preheat And Dhw Function, Fault Finding Diagrams

57

PREHEAT AND DHW FUNCTION

INSTALLATION

FAULT FINDING

& DIAGRAMS

Tap open

(recognised

by flow turbine)

Wait

5 seconds

DOMESTIC

HOT

WATER

DEMAND

(priority over

all other

demands)

Gas valve OFF.

Burner shut down if primary temperature 94°C

(until 84°C)

Over temperature shut- down if water tempera- ture is 8°C above set value.

Fan (& gas) modulation to achieve set temperature (40-60°C)

DEMAND

END

& SERVICING INSTRUCTIONS FOR

POWER	BLUE
SWITCH	LIGHT
ON	ON

ECO button

not

illuminated *

(ie preheat requested)

AND

Diverter valve	Fan to	IGNITION	GREEN
in DHW			FLAME
	start	SEQUENCE
position			LIGHT
	speed.	(see detail)
Pump ON.			ON

Gas valve

OFF

Pump run 3

minutes

Fan run 30

seconds

WORCESTER GREENSTAR 24 i junior/28 i junior 8 716 107 336b (11/05)

*Set by

pressing ECO button. If pro- grammer is fitted this is set by a combination of programmer (DHW) demand and ECO button.

20minutes since last pre- heat demand

AND

temperature at least 10° below set point.

PREHEAT

DEMAND

LOCKOUT

	IGNITION SEQUENCE						Fan (& gas)
							modulation
							to achieve
						YES	(55°C)
		Spark		BURNER
		ignition
				LIT?
		4 seconds
YES			NO		NO
		5th		Stop spark.
				Wait
		attempt?
				10 seconds

DEMAND

END

Gas valve

OFF

Stop pump

Stop fan

PREHEAT AND DHW FUNCTION