11
Fig. 13. Functional flow diagram.
On/Off
swit
ch
ST2
(L
S
)
ST2
(L
R
)
ST2
(N
S
)
ST1
centr
e
pin
ST15
right
pin
Pump
Fan
ST2 Pin N
Optional link
R
oom
thermost
at
Tr
ansf
ormer
Fuse F2
(1.25A Slow)
Fuse F1
(2A Slow)
N
N
ST2 Pin L
LIVE
IN
Electronics
Electronics
Inputs
Outputs
Spark
Indicat
or
s
Settings
R
egulat
or v
alv
e
Spark
electr
odes
Err
or
indicat
or/r
eset
Re
d
M
ain v
alv
e
Flow sensor
CH sensor
DHW sensor
Air pr
essur
e swit
ch
Flame sense
Ov
erheat cut-off
24V pr
ogr
ammer (if applicable)
Gas valve mode switch
CH Control knob
DHW control knob
Convert AC to low
voltage electronics
Electronics/
microprocessor
(Safety Low Voltage)
Flame detect
indicat
or
Re
d
ST2
centr
e pole
(Ls)
(for other featur
es)
low
high
Electronics
ST1
right
pin
Reset button
white
re
d