gledhill Torrent GreenHeat TGH140-OV Design, Installation & Servicing Instructions page 22

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 benefi 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 off 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 fl 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
different fl 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.
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