Grasslin Towerchron QM1 Installation And User Instructions Manual page 12

Saunier Duval SD625M
Always use special 24V thermostat supplied with this boiler, and wire as indicated in boiler instructions
substituting time switch terminals A and B for terminals 3 and 4 respectively on QM1�
Boiler with timeswitch and room thermostat
frost protection
thermostat (if required)
K J
240V
3 AMP
N 1
fused
supply L
E 6
boiler connection box
12
timeswitch
A B E L
240V 3 AMP
fused supply
thermostat
2 3
5 4 D C H
ground
Elm Leblanc GVM 420
220/240V
50 Hz AC
N main supply
N
room stat
D
D = demand
S = satisfy
COM = common
L 1 2 3 4
COM�
S
N
L
boiler terminals