Preheat And Dhw Function - Worcester GREENSTAR 25Si Instruction Manual

FAULT FINDING
& DIAGRAMS
Tap open
(recognised
by flow
turbine)
POWER BLUE
SWITCH LIGHT
ECO button
ON ON
not
illuminated *
(ie preheat
requested)
AND
20 minutes
since last pre-
heat demand
AND
temperature
at least 10°
below set
point.
*Set by pressing and holding
ECO button for 3 seconds.
If programmer is fitted this is set by
a combination of
programmer (DHW) demand and
ECO button.
Wait
Gas valve OFF.
5 seconds
DOMESTIC
HOT
WATER
DEMAND
(priority over
all other
demands)
Diverter valve
Fan to
in DHW
start
position
speed.
Pump ON.
IGNITION SEQUENCE
PREHEAT
DEMAND
Spark
ignition
4 seconds
NO
YES
5th
LOCKOUT
attempt?
Burner shut down if
primary temperature
94°C
(until 84°C)
Over temperature
shut-down if water
temperature is 8°C
above set value.
Fan (& gas)
modulation
to achieve
set
temperature
(40-60°C)
GREEN
IGNITION
FLAME
SEQUENCE
LIGHT
(see detail)
ON
Fan (& gas)
modulation
to achieve
(40-60°C)
YES
BURNER
LIT?
NO
Stop spark.
Wait
10 seconds
DEMAND
END
Gas valve
OFF
Pump run 3
minutes
Fan run 30
seconds
DEMAND
END
Gas valve
OFF
Stop pump
Stop fan