Instruction Manual
10
It is important that you always refer to 
the Boiler Manufacturers Instructions 
concerning electrical wiring before using 
the information contained in this leaet� 
In some cases the Boiler Manufacturers 
Instructions will contain information 
regarding removal of certain link wires 
and will always indicate the fuse rating 
for the main electrical supply�
Important note:
Combination Boiler Model
Chaffoteux Celtix 2�20 OFF N PH 7 6
FIM Leblanc GVM 420 see special circuit
Glowworm Fuelsaver N L 8 7
Ravenheat N L C D
Saunier Duval SD 620 F N L 2 3
Saunier Duval SD 123C N L 2 1
Saunier Duval SD 235C N L 2 1
Saunier Duval SD 135C N L 2 1
N
D S
room stat
D = demand
S = satisfy
QM1 Terminals
220-240V AC 
50 Hz 
FUSED 
SUPPLY
L 1 2 3 4










