Worcester 25Si User Manual

11
Fig. 12. Functional flow diagram.
Mains
indicator
On/Off
switch
ST8
(L
S)
ST8
(L
R)
ST8
(N
S)
ST1
Centre
Pin
ST15
Pin L
REL 1 REL 3
Pump
Fan
ST12 Pin N
Optional link
Room
thermostat
Transformer
Fuse F2 (1.6A
Slow)
Fuse F1
(2A Slow)
N
N
ST12 Pin L
LIVE
IN
green
Electronics
Electronics
Electronics
Inputs
Outputs
Spark Indicators
Settings
Regulator valve
CH
demand
indicator
Red
Spark
electrodes
DHW
demand
indicator
Red
Flame
detect
indicator
Red
Main valve Main valve Flow switch CH sensor DHW sensor Air pressure switch Flame sense Overheat cut-off 24V programmer
Reset button
Gas valve mode switch
CH pressure adjust pot
CH Control knob
DHW control knob
Convert AC to low
voltage electronics
Electronics/
microprocessor
(Safety Low Voltage)

Worcester 25Si Specifications

General

Model	25Si
Category	Boiler
Output	25 kW
Efficiency Rating	A
Dimensions	710mm x 400mm x 330mm
Fuel Type	Natural Gas
Flow Rate	10.2 l/min
Boiler Type	Combi
Mounting	Wall-mounted
ERP Rating	A
DHW Output	25 kW
Hot Water Flow Rate	10.2 l/min
Max Working Pressure	3 bar
Warranty	5 years
CH Output	25kW