6
OPERATOR CONTROLS
2
Fig. 2-2a High Limit Thermostat
Hot Supply
Option A
Cylinder with immersion heater.
Water can be heated by any
conventional method.
Pressure relief valve
vents excess pressure
from Hot Water System.
Hot Water Cylinder is
at ‘Mains Pressure’
due to incoming cold.
Rubber expanding
bladder inside vessel.
Pressure is maintained
at maximum ‘Mains
Pressure’
Air Pressure
Diaphragm
Accumulator
Mains Water
Existing
Mains Supply
Non-return valve. As
water is used system is
equalised to maximum
‘Mains Pressure’.
(Indirect unit)
2-2 HOT WATER OVERHEATING
2-2.1 Water Heated by Heating System
When the hot water is heated by the heating system a High Limit
Thermostat prevents the water within the Cylinder overheating.
In the event of the water temperature within the Cylinder reaching
85°C the thermostat will trip and close the Motorised Valve shutting
off the flow from the heating system - see fig. 2-2a.
The High Limit Thermostat is a manual reset type, this means that
it has a button that pops out when the thermostat has been tripped
by overheating - see fig. 2-2a.
To reset the system after overheating allow time for the water to
cool, or run off some hot water, then remove the electrical box cover
and press the High Limit Thermostat manual reset button.
If the High Limit Thermostat trips more than once, switch off the
heating system and Immersion Heater and contact your installer.
2-2.2 Water Heated by Immersion Heater
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.
WARNING:
When the cover is removed electrical live terminals are exposed.
ALWAYS TURN OFF THE ‘WATER HEATER’ SWITCH BEFORE REMOVING COVER.
Note: The High Limit temperature of 85°C is factory set and cannot be changed.
2-3 SHUT OFF VALVES
The OSO Dualstream installation will
have a number of shut off valves, the
location of these will be dependent on
the installation - fig. 2-3a shows a
typical layout.
IMPORTANT:
Before closing ANY valve:-
1. Switch OFF the Electric
Immersion Heater.
2. Turn OFF the Heating System.
Note: When operating the stop cock
turn the valve fully open then close
1
⁄
2
turn, this prevents the valve
sticking.
Fig. 2-3a Typical Shut Off Valve Locations
High
Limit
Adjustment
screw
Cylinder thermostat located
in electrical box