47
CIRCUIT DIAGRAM 20 MCS
BM
Modulating coil
CA
Ignition control unit Honeywell
CR
Remote control - room thermostat
CiR
Circulating pump
EC
Control electrode
ES
Spark electrode
KA
Anti-freeze thermostat (on request)
L
Line
MAX R
Max. heating setting
N
Neutral
PF
Fumes pressure switch (Honeywell)
Pma
Lack of water pressure switch
PR
Reset push-button
P.risc.
Heating potentiometer
PS
Hot water pressure switch
P.san.
Hot water potentiometer
RA
Anti-freeze element (on request)
RF
Anti-interference resistance
SB
Lock-out warning light
SC
Connection card
SR
Heating detector
SRT
RX-TX board
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:
Check that the
microswitches on selector
SW1
are as illustrated in the
diagram.
To install the room thermostats
TL
remove the bridges
and connect up using the supplied fairlead
