48
PRINCIPLE DIAGRAM 24 MCS
BM
Modulating coil
CA
Ignition control unit Honeywell
CiR
Circulating pump
EC
Control electrode
ES
Spark electrode
L
Line
MAX R
Max. heating setting
N
Neutral
PF
Fumes pressure switch (HUBA)
Pma
Lack of water pressure switch
PR
Reset push-button
P.risc.
Heating potentiometer
PS
Hot water pressure switch
P.san.
Hot water potentiometer
RT
RL3 relay contact
RS
R4 relay contact
RP
RL2 relay contact
RF
Anti-interference resistance
SB
Lock-out warning light
SR
Heating detector
SS
Hot water/water-heater detector
SW1
Function selector
TIMER
Boiler timer adjustment
TR1
Transformer
TST
Total safety thermostat
V
3-way valve
VG
Gas valve
VN
Fan
TL
Limit thermostat (if any)
LEGEND
NOTE: Slow ignition (RLA) is of the mechanical type positioned on the gas valve as illustrated in the figure on page 68
.
