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5.4 DIGITAL DUAL THERMOSTAT
A Digital Dual Thermostat (a combined control and high limit
thermostat) is supplied factory tted to the Grant QR integrated
indirect heat pump cylinder to control the operation of the heat
pump primary coil. Refer to Figure 2-2 for position.
The cylinder control thermostat has an adjustment range between
25°C and 65°C. It is recommended that it is set to 60°C.
The high limit (overheat) thermostat will automatically operate at
80°C.
For details on wiring connections, refer to Figures 5-2 and 5-3.
For more detailed information on the Digital Dual Thermostat
supplied with this cylinder, please refer to Appendix A at the back
of these instructions.
! NOTE !
Upon rst use it will be necessary to reset the digital dual
thermostat.
To do this, please refer to steps 1-3 outlined in Section
A.1.2 at the back of these instructions.
! NOTE !
The Digital Dual Thermostat supplied with all Grant QR
integrated cylinders requires a permanent live connection.
Refer to Figures 5-2 and 5-3 for wiring details.
! WARNING !
The Digital Dual Thermostat supplied with all Grant QR
integrated cylinders is not suitable for use with a Y-plan
type control system using a Honeywell V4073A mid-
position zone valve (or similar).
5.5 2-PORT VALVES
To comply with the regulations governing the installation of indirect
unvented hot water cylinders, a motorised valve is supplied tted
in the primary ow to prevent gravity circulation when the boiler or
heat pump switches o. Refer to Figure 2-2 for position.
This acts as a positive energy cut-out should the high limit
(overheat) thermostat (in the dual thermostat) operate. If this
happens, the motorised valve will operate and shut o the primary
ow to the cylinder.
When installed as part of an “S-plan” type of heating control
system, this motorised valve will also control the temperature of
the domestic stored water via the cylinder control thermostat,
(located in the dual thermostat).
It is wired in accordance with Figure 5-2 to comply with current
legislation.
For air source heat pumps other than the Grant Aerona³, consult
the heat pump manufacturer for electrical connection details.
5.6 CYLINDER WIRING
The Grant QR integrated indirect heat pump cylinder is supplied
factory tted with the following electrical equipment:
• 1 x Grant EP001 Wiring Centre (pre-wired to the zone
valves and dual thermostat). Refer to Section 5.8 for further
information.
• 2 x 2-port zone valves for space heating (for two separate
heating zones)
• 1 x 2-port zone valve for hot water
• 1 x 3kW electric immersion heater
• 1 x Greenbrook T205-C timer (for immersion heater)
• 1 x Dual thermostat (cylinder thermostat and high limit
thermostat)
These are pre-wired to the factory-tted Grant EP001 wiring
centre mounted on the cylinder. Refer to Section 5.8 and Figures
5-2 and 5-3 for details.
5.7 GREENBROOK T205-C TIMER
Grant QR integrated indirect heat pump cylinders are supplied
with a Greenbrook T205-C timer factory tted, to control the
operation of the immersion heater for anti-legionella purposes.
Please refer to the current Aerona³ installation instructions for
detailed information on anti-legionella regimes.
Please refer to Figures 5-2 and 5-3 for connection details and
Appendix B at the back of these instructions for information on
how to set the Greenbrook T205-C timer.
5.8 GRANT EP001 WIRING CENTRE
The Grant EP001 wiring centre is supplied factory tted to Grant
QR integrated indirect heat pump cylinders and is wired as shown
in Figure 5-2.
The Grant EP001 wiring centre has been designed as a simple
and convenient means of making all system control connections
for up to four space heating zones, plus one hot water zone, in
one wiring centre, with optional capability to provide both volt free
outputs and automatic DHW priority (for Grant Aerona³ heat pump
installations).
For further information on the Grant EP001 wiring centre, please
refer to the EP001 installation instructions.
! NOTE !
All earth connections for electrical components connected
to the EP001 wiring centre should be made to the brass
earth bar on the inside of the EP001 wiring centre
enclosure.
To make connections to the EP001 wiring centre:
1. Remove the lower front panel of the cylinder enclosure (refer
to Figure 2-1).
2. Remove the two screws on the underside of the EP001
wiring centre securing the wiring centre cover.
3. Carefully lift o the wiring centre cover and remove the earth
cable connected to the wiring centre cover from the earth
block, taking care not to damage the earth cable.
4. Route external wiring to the EP001 wiring centre through
the cable entry points on the rear top panel of the cylinder
enclosure (see Figure 2-1). To do this, rst push through
the required “knock-out” and t one of the cable glands
provided in the accessories kit supplied with the cylinder (as
necessary) to the chosen knock-out.
! WARNING !
Ensure that the electrical supply has been isolated before
making any connections to the EP001 wiring centre.
Section 5: Electrical
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