Immersion heaters
All units are fitted with one immersion heater which is located behind the lower electrical box.
Wiring instructions for the immersion heater is located on the reverse side of the lower lid. Follow
the wiring instructions connecting the live, neutral and earth as indicated. The electrical connection
to the immersion heater must conform to current IEE wiring regulations. The unit must be
permanently connected to the electrical supply through a double-pole linked switch with a
minimum break capacity of 13 amps. All internal wiring is factory mounted. Each immersion
heater has a working thermostat adjustable between 40°C - 70°C. A safety cut-out is also
incorporated within the thermostat and will operate at 85°C ± 3°C. Should this happen, press the
reset button.
Important: Before resetting the safety cut-out or altering the thermostat setting, isolate
electrical supply to the unit prior to removal of the lid. Ensure the lid to the electrical box
is replaced correctly and the retaining screw is fitted.
Indirect Units upper coil
Motorised valve
To comply with regulations governing the installation of indirect unvented cylinders, a motorised
valve must be fitted in the primary flow. Your OSO unit has been supplied with a two port
motorised valve, which will act as a positive energy cut-out should the safety cut-out operate.
The motorised valve will also control the temperature of the domestic stored water via the
cylinder thermostat, which is located in the upper electrical box. The unit should be installed on
an “S” or “Y” plan system. Cylinder temperature control can also be achieved via the solar
thermostat when the boiler is not operational.
Please follow the instructions carefully.
All electrical connections must conform to current IEE
wiring regulations. The working thermostat is adjustable between 40°C - 70°C. A safety cut-out
is also incorporated within the thermostat and will operate at 85°C ± 3°C. Should the safety
cut-out be brought into operation, the motorised valve will operate and close down the primary
flow to the cylinder. To reset the safety cut-out and the motorised valve the reset button must be
pressed in (see fig.4 page 8).
Lower (Solar) coil
Heat sources to unvented hot water cylinders must be controlled by a thermal cut-out as well as
a thermostat. The OSO Solarcyl is supplied both with bosses for solar sensor pockets and the
pockets themselves.
The top half of the thermostats fitted to the cylinder is a thermal cut-out. The solar controller (not
supplied) and solar sensor point should be wired through the OSO thermal cut-out. See fig. 4
pages 8 & 10.
Please note that the direction of flow in the solar coil is reversed compared to the boiler coil. If
the cylinder is not being used for solar use, connect the boiler to the lower coil with the primary
flow in a bottom to top direction.
OSO Hotwater (UK) Limited can not be responsible if alternative wiring plans are used.
Important: Before resetting the safety cut-out or altering the thermostat setting isolate
electrical supply to the unit before removal of the lid.
ELECTRICAL INSTALLATION
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