Worcester 12/14 Installation And Servicing Instructions page 16

Note: The mains supply cable should not be connected to an
external time switch when a frost thermostat or low-level
discharge post purge unit is fitted to the Danesmoor standard
wiring block.
NOTE: Under no circumstances should the timer be connected
to a separate electrical supply. Safety is assured from a single
fused supply to the boiler.
10.5 Safety Check
In the event of an electrical fault after the installation of the
appliance, the electrical system shall be checked for short
circuits, fuse failure or incorrect polarity of connections.
10.6 Pre-wired Remote "Y" or "S" Plan systems
(See Fig. 17).
If the system is fully pre-wired at a junction box remotely from
the boiler, it can be connected to the boiler. The diagram shows
connection details of two proprietary systems (Honeywell and
Invensys).
The WHS facia mounted programmer can be fitted instead of an
external timer to the remote junction box. Remove the operating
switch plug and connect the programmer plug into the time
clock connector. Connect terminal 1 from the boiler terminal
block to the 'HOT WATER ON' on the remote 10 way junction
Fig. 15. Frost Protection.
Terminal strip
6
5
4
3
2
1
N
E
E
N
L
Fig. 16. Programmer Connections.
(a) Internal Programmer
7 8 9 10
Blue
Programmer
box. Connect terminal 2 from the boiler terminal block to the
'HEATING ON' on the remote 10 way junction box.
NOTE: A "Y" Plan requires a live feed from the 'HOT WATER OFF '
switch position. In order to achieve this, using a WHS program-
mer, remove the orange wire from terminal 9 and pull back
through the tie wraps. Ensure the brown wire is firmly secured in
terminal 9. Connect the orange wire to terminal 6 on the boiler ter-
minal block and connect terminal 6 to the 'HOT WATER OFF' con-
nection at the remote 10 way junction box.
10.8 Honeywell "S" Plan
(See Fig. 18).
The "S" plan provides complete control on installations having
pumped circulation to both the domestic hot water and radiator
circuits.
The domestic hot water and radiator circuits are independently
controlled by two motorised valves via a cylinder thermostat
and a room thermostat. Both thermostats switch the water
circulator and the boiler on and off.
10.9 Honeywell "Y" Plan
(See Fig. 19).
The "Y" Plan provides complete control on installations having
pumped circulation to both the domestic hot water cylinder and
radiator circuits.
The domestic hot water and radiator circuits are controlled by a
3 port motorised valve via a cylinder thermostat and a room
E
thermostat. Water flow is diverted to either circuit or to both
circuits at the same time. Both thermostats switch the water
circulator and the boiler on and off.
Note: The "Y" plan requires a live feed from the hot water "off"
switch position. In order to achieve this, using a WHS
programmer, remove the orange wire from terminal 9 and pull
5
back through the tie wraps. Do not attempt to cut the tie wraps.
4
Ensure that the brown wire is firmly secured in terminal 9.
3
Connect the orange wire to terminal 6.
10.10 Frost Protection
2
(See Fig. 15).
For full frost protection a single pole double switch thermostat
should be fitted so that both the boiler and the circulating pump
circuits are energised under frost conditions. Frost protection
will be lost if there is no power supply to the appliance..
1
Pre-wired time clock
terminal strip socket
(Located in boiler
electrical cover).
Pre-wired time clock
terminal strip plug
(Connected to time
clock leads).
16
(b) External Programmer
6
5
4
HW
3
CH
2
1
N
E
E
E
N
N
L
L
7 8 9 10
Note: Remove link plug 8 & 9.