8 electrical, Electrical – Grant Products HPAW155 User Manual
The Grant Aerona Heat Pump is very simple to install and to wire. The units are designed
to meet the need for simplicity – both in installation and in servicing. As a result, the
wiring involved is both minimal and simple compared to other heat pumps available.
For Monovalent systems, the following cables are required.
a) 1 x twin and earth cable suitable for the current and length of run from the
consumer board to the external isolator.
b) 1 x 3-core SWA suitable for the current from the external isolator to the heat
1 x 3-core 0.75mm² from the systems wiring centre to the heat pump
d) 1 x 3-core umbilical cable from the heat pump to the ATC (heat pump controller)
mounted inside the house. A 5m length of this cable, complete with fitted plugs is
supplied with the heat pump.
For Bivalent systems, an additional 2-core 0.75mm² cable is required from the heat
pump to the boiler.
8.2 Basic Circuits – Making the Connection
The diagram below is of a typical S-Plan type control system as used with a gas or oil fired boiler.
FOR INFORMATION ONLY – DO NOT FOLLOW THIS DIAGRAM AS IT WILL CAUSE IRREPARABLE
DAMAGE TO THE HEAT PUMP.
All electrical work must be undertaken by a competent person. failure to observe
this legislation could result in an unsafe installation and will invalidate all warranties.
Hlg Zone V
DHW Zone V
Boiler & System
Note that the two wires that feed
both motorised valves to Gr (grey)
terminate at L, giving them a
permanent supply of 230Vac.
The two wires leaving the motorised
valves at O (orange) are the switched
output and will also be at mains
potential. The switches inside the
motorised valves make the
connection between L (permanent
Live) and 10 (switch live) to feed the
boiler and the pump.
In contrast, the heat pump switches
at 0V and therefore a simple re-wiring
(for existing systems) must take
place at the wiring centre before it is
safe to connect to the heat pump.
It is possible for some components
to have 2 power supplies feeding
them. It is also possible for mistaking
an internal circuit to be dead when it
is receiving power from another
source. Please label all controls and
devices if this is possible, advising to
check and isolate in one or more
locations as required.
To help remove as much of this risk
as possible, take all heating system,
heat pump and immersion element
circuits from a single supply at the
Figure 8-1: S-Plan type system for normal boiler connection