50
yebk whgy bu rd
bk gy
gy
gy
M
t
COM
NO
COM
NO
NC
bk
bubn
rd
gnyegywh
bu
rd
bk
bu
wh
gybugnye
bkbk
ubeyngyg
bk
bk
bubu
bu
bu
rdbk
ygyg
L N
rd bubn gnye gnye
gnye bubn
burd
gnye
wh
gy
rd
bk
bu
bn
gy
ye wh burd
bk
rd

Caution: Label all wires prior to disconnection when

servicing controls. Wiring errors can cause

improper and dangerous operation.

Verify proper operation after servicing

Flue
thermostat
Safety
thermostat Air pressure
switch Ignition
electrodes Flame detection
electrode
FanElectric supply
terminal block
External controls
terminal block
3 2 1
Prmary circuit
flow switch Pump Gas valveC.h. temperature
probe NTC
bn - brown
bu - blue
bk - black
gn - green
gnye - green / yellow
gy - grey
or - orange
rd - red
wh - white
vt - violet
ye - yellow
or
rd rd
t
rd
whbu
bk
rd
wh bk rd

~

31
2
wh
**D.h.w.
**flow switch
**D.h.w.
**NTC
**Three way
**diverter valve
rd
rd
rd
wh
bu
wh
wh
or
~
M
M
~
*--- directly connected to the electronic ignition board
** - Not for model c.h. only
Figure 11.7: Internal Boiler Wiring