
Fully Pumped Heating System using SRT323 room
stat, cylinder stat and Three Port Mid Position
Valve with a Secure SHP021/SHP027 electronic
programmer.
This diagram is schematic and should be used for
guidance only.
17
1
2
3
4
5
6
L
N
MAINS
SUPPLY
E
N
L
1
4
1
4
FROST
STAT IF
FITTED
SRT323
ROOM
STAT
CYL
STAT
W
BL
0
GR
MRG POSITION VALVE
PUMP &
BOILER
L
N