Grant Aerona 3 HPID10R32, Instructions Manual, Page: 38 / 100

Page 38 Section 8: Operation
8.4 FROST PROTECTION
Frost protection can be activated when the heat pump is in OFF
mode.
This is based on either:
•
Outdoor air temperature - refer to Section 8.4.1 and Figure
8-10.
• Flow water temperature - refer to Section 8.4.2 and Figure
8-11.
• Room air temperature - refer to Section 8.4.3 and Figure 8-12.
This function is not required if ethylene glycol (heating system
antifreeze) is used in the heating system water. Refer to Section
3.11.2 for guidance on how to switch off the frost protection
function.
8.4.1 FROST PROTECTION BASED ON OUTDOOR AIR
TEMPERATURE
This frost protection function is always active, even when the heat
pump is not operating (but the mains supply is switched on).
The water pump is activated if the outdoor air temperature
(measured by the heat pump outdoor temperature sensor) is less
than the start temperature - parameter 4311 (default: 4°C).
It is deactivated when the outdoor air temperature reaches ‘outdoor
air temperature set point + Hysteresis’ - parameter 4311 plus the
hysteresis parameter 4312 (default: 7°C).
The ‘frost protection’ symbol (
) will be displayed on the remote
controller screen when this frost protection function is in operation.
Under low ambient air conditions the water pump may operate for
an extended period to provide frost protection when the heat pump
is not operating, e.g. possibly throughout the night, until the heat
pump starts the following morning.
Whilst the water pump may operate for long periods, when the
prevailing conditions dictate, the cost to protect the heat pump from
freezing is small due to the low water pump power consumption.
8.4.2 FROST PROTECTION BASED ON FLOW WATER
TEMPERATURE
This frost protection function is always active, even when the heat
pump is not operating (but the mains supply is switched on).
The water pump is activated if the flow water temperature is less
than the start temperature - parameter 4321 (default 4°C).
It is deactivated when the flow water temperature reaches ‘flow
water temperature set point (parameter 4321) + hysteresis -
parameter 4322 (default 3°C)’.
The ‘frost protection’ symbol (
) will be displayed on the remote
controller screen when this frost protection function is in operation.
Under low ambient air conditions the water pump may operate for
an extended period to provide frost protection when the heat pump
is not operating, e.g. possibly throughout the night, until the heat
pump starts the following morning.
Whilst the water pump may operate for long periods, when the
prevailing conditions dictate, the cost to protect the heat pump from
freezing is small due to the low water pump power consumption.
8.4.3 FROST PROTECTION BASED ON ROOM AIR
TEMPERATURE
This frost protection function is always active, even when the heat
pump is not operating (but the mains supply is switched on).
The water pump is activated if the room air temperature (measured
by the heat pump remote controller) is less than the start
temperature - parameter 4301 (default: 14°C).
It is deactivated when the room air temperature reaches ‘room
air temperature set point + Hysteresis’ - parameter 4301 plus the
hysteresis parameter 4302 (default: 1°C).
The ‘frost protection’ symbol (
) will be displayed on the remote
controller screen when this frost protection function is in operation.
Under low room air conditions the water pump may operate for an
extended period to provide frost protection when the heat pump
is not operating, e.g. possibly throughout the night, until the heat
pump starts the following morning.
Whilst the water pump may operate for long periods, when the
prevailing conditions dictate, the cost to protect the heat pump from
freezing is small due to the low water pump power consumption.