LEGEND
BM Modulating coil
CiR Heating circulator
EA Ignition electrode
EC Control electrode
F Fuse 2(A)
JP1 Methane/LPG selector
JP3 Post-circulation selector
JP4 Ignition limiting selector
JP5 Jumper to be cut for low temperature
JP6 Mono-thermal/bi-thermal switch
L Phase 230 V 50 Hz
MP
Hot water priority micro pressure switch
N Neutral
PA Air pressure switch
PS No-water pressure switch
RLA Slow ignition power adjustment
Rmax. Heating max. power adjustment
SR Heating sensor
SS Hot water sensor
TA Room thermostat (if any)
TL Limit thermostat (if any)
TST Safety thermostat
VG Gas valve SIT 837
VG1
Gas valve Honeywell
VK 4105M
VN Fan
1 Heating potentiometer
2 Selector: Off
Summer
Winter
Reset
Test
3 Hot water potentiometer
Warning: One of the two gas valves only, VG or VG1, is fitted on the boiler.