gledhill Torrent GreenHeat OV TGH140 Design, Installation & Servicing Instructions page 12

INSTALLATION
HP Model With Central Heating From Heat Pump
3-port
diverter
valve
PRV
HP Model With Central Heating From Thermal Store
PRV
TORRENT GREENHEAT HP
Torrent Green HP Models
The Torrent GreenHeat HP models are all open
vented and are designed to be heated directly
by an air or a ground source heat pump which
does not require a minimum pressure in the
Min. 250mm
primary circuit for operation. The space heating
can be supplied directly from the heat pump
circuit or from the thermal store.
The selection between the two options will
depend upon the operating characteristics of
the heat pump, type of heating system and
control strategy. For general guidance: -
• If the heat pump requires a buffer for
operation; for example to reduce rapid
cycling etc, then the system would bene t
if the heating system is supplied from the
thermal store. In this configuration, the
operation of the heat pump is only controlled
by the store thermostat(s).
• A hybrid system arrangement can also
be used (not shown). For example; a low
temperature weather compensated heating
circuit e.g. under floor heating can be
supplied directly from the heat pump circuit
and constant temperature e.g. towel rails
can be supplied from the thermal store.
A typical wiring arrangement for a system in
which the space heating is supplied from a
Torrent GreenHeat HP is shown on page 34
and a typical wiring arrangement for a system
in which the space heating is supplied from a
heat pump circuit is shown on page 35.
On page 34, the control of heat pump is shown
Min. 250mm
with top and bottom thermostats to enhance the
performance of the heat pump by decreasing the
frequency of cycling. The heat pump is switched
on when both top and bottom thermostats are
calling for heat and is switched o when both
thermostats stop calling for heat. A two channel
programmer suitable for gravity hot water
system should be used with this arrangement.
On page 35, the generic wiring arrangement
is shown with a 3-port diverter valve with hot
water priority. If a 3-port ow share valve is used,
then the controls should be wired to provide
priority for hot water because the space heating
and the hot water heating may be operating at
di erent ow temperatures.
Technological advancement of heat pump
control systems is occuring at a fast pace and
the conrol systems supplied with the heat
pump can provide full control of the system. It
is also important to ensure that the minimum
head for the heat pump and the system pump
is as required by the heat pump manufacturer.
Please refer to the heat pump manufacturers
instructions to obtain further information.
Page 22
HP SOL Model With Central Heating From Heat Pump
Solar
controller
Solar pumping station
Pressure Expansion
relief vessel
3-port
diverter
valve
PRV
HP SOL Model With Central Heating From Thermal Store
Solar
controller
Solar pumping station
Pressure Expansion
relief vessel
PRV
Page 23
INSTALLATION
Torrent GreenHeat HP-Solar Models
The heat pump and space heating system
con gurations and operation with the Torrent
GreenHeat HP-solar models is the same as for
standard models. The solar thermal system
operates independent of the heat pump system.
A typical generic solar system con guration is
Min. 250mm
shown for guidance only. The solar system and
the associated controls should be planned and
installed following manufacturers instructions.
All components in the solar primary system
must be marked or identi able in such a way
that their design pressure and temperature can
be readily determined.
A safety device i.e. pressure relief valve to
control the risk of over-pressure in the system
components should be tted as per solar system
manufacturers instructions. A termination from
the pressure relief valve should minimise the
risk of damage to persons or materials. Suitable
locations are a high temperature receptacle,
internal gully or else externally at ground level.
High level termination from a wall or on a roof
could cause injury to people or animals below
if the valve were to release scalding water and
steam.
The pipe leading to from the safety device to the
collector should be rigid and non-deformable
construction, without any possibility of
restriction, distortion or closure by any other
tted component.
A typical wiring diagram for the solar thermal
system for the Torrent GreenHeat HP-solar is
shown on page 35.
Min. 250mm
To ensure e ective operation of the thermal
store it must not be overheated. Therefore
an overheat thermostat or other device must
be tted to ensure that this does not occur.
Ideally the control thermostat should be set
to a temperature which does not allow the
temperature at the top of the store does not rise
above the low 80s. This means that the control
thermostat may need to be set at 70°C on some
cylinders, due to the temperature gradient in
the store. The actual set point must set up and
checked during commissioning by the installer.
The overheat thermostat should be set at a
temperature which operates before or at 85°C.
The control packages supplied with the heat
pump can not only control the heat pump but
any backup devices as well, for example, solar
thermal, gas boiler and immersion heater ow
boilers.
TORRENT GREENHEAT HP SOL