Section 8: Electrical
Page 31
10. Locate the two terminal block cover fixing screws. Refer to Figure
8-5.
Figure 8-5:
Terminal block cover fixing screws
11. Unscrew both screws and remove the cover from the boiler.
12. After making the electrical connections the terminal block cover
must be re-fitted using the reverse of this procedure.
8.3 Remote Grant Logo indicator Connections
The Grant logo indicator, supplied with the boiler, should be mounted
on a standard electrical back box (either recessed or surface
mounted) in a convenient and visible position within the house.
Using a suitable length of 0.75mm² 2-core PVC flex, connect the
remote Logo indicator to the corresponding terminal block in the
boiler. This terminal block is located to the left of the main boiler
terminal block, at the front lower left corner of the boiler (behind the
inner access cover). Refer to Figure 8-6 for electrical connection
details.
When connecting the Remote Grant Logo Indicator, ensure that the
terminal with the red wire on the boiler terminal block is connected to
the terminal with the red wire on the logo indicator terminal block.
Likewise, ensure that the terminals with the black wire on both the
boiler and logo indicator terminal blocks are connected together.
VECTA
GRANT
Black
Red
Red
Black
Figure 8-6:
Connection diagram for Remote Grant Logo Indicator
8.4 Connecting the Power Supply
Before making any connections to the heating systems controls
ensure that the electrical supply is isolated at the fused spur
serving the controls and boiler, that the fuse has been removed
and the isolator is locked off.
!
WaRninG
Use a suitable length of 4-core flex, at least 1.5mm
2
PVC between the
heating controls wiring centre or junction box and the terminal block in
the boiler. Ensure that the flex passes through and is secured by the
cable clamp next to the terminal block.
Connect the mains supply to the boiler terminal block from left to
right, as per Figure 8-7.
2 3
SWITCHED LIVE
PERMANENT LIVE
NEUTRAL
EARTH
SIDE STORE NEUTRAL
SIDE STORE EARTH
SIDE STORE LIVE
1
Figure 8-7:
Boiler terminal block
if the 4-core flex between the heating controls aand the boiler
terminal block is damaged at anytime, it must be replaced by
a comptent engineer in accordance with the requirements of
the Electricity at Work Regulations 1989 and BS7671:2008 – iEt
Wiring Regulations 17th Edition (including all amendments).
nOtE
!
8.5 Heating System Controls
The boiler can be used in conjunction with typical heating control
system, e.g. ‘S-Plan’ or ‘Y-Plan’ type controls. Refer to Figures 8-9 and
8-10 for typical control system wiring diagrams.
8.6 Frost Protection
The Grant External Vecta wood pellet boiler is supplied with a factory-
fitted frost protection thermostat. This is pre-set to operate when the
air temperature falls to 2°C.
This frost thermostat is located inside the PCB enclosure and is
connected between the Terminal 2 and Terminal 3 on the boiler
terminal block.
For details of the frost thermostat electrical connections refer to
Figures 8-8 and 8-9.
in order for the frost protection thermostat to operate, ensure
that a link is fitted between terminal 1 and the permanent live
terminal on the boiler terminal block.
nOtE
!
Grant recommends the use of a pipe thermostat (not supplied) in
conjunction with the frost thermostat to avoid unnecessary and
wasteful overheating of the property. This pipe thermostat should be
located on the boiler return pipe and set to operate at 25°C.
To connect a pipe thermostat:
•
Remove the factory fitted link between terminals 1 and 2 on the
boiler terminal block.
•
Connect the pipe thermostat between terminals 1 and 2 on the
boiler terminal block.
Refer to the Figures 8-8 and 8-9 for details of the frost thermostat and
pipe thermostat electrical connections.
For total system protection against freezing, particularly during
extended periods without electrical power, Grant recommends the
use of a combined heating system antifreeze and corrosion inhibitor,
used in accordance with the manufacturer’s instructions.
