Buffer Tanks; S-Plan With Buffer - Monovalent - Grant Aerona HPAW65 Installation & User's Instructions

4 Hydraulic Diagrams
IMPORTANT
The following system diagrams
are only concept drawings and
not detailed engineering
drawings. They are not intended
to describe complete systems,
nor any particular system.
It is the responsibility of the
system designer, not Grant
Engineering UK Ltd., to
determine the necessary
components for and
configuration of the particular
system being designed including
any additional equipment and
safety devices to ensure
compliance with building and
safety code requirements.

4.6 S-Plan with Buffer - Monovalent

Grant Aerona
Heat Pump
Primary
Pump
Figure 4-5: Monovalent system - with Buffer and S-Plan type controls
12
4.5 Buffers Tanks
The use of a buffer with the current
Aerona heat pump is not necessary in
the majority of installations. However, it is
possible to utilise a buffer if the end-user
wishes to store hot water when there is
no other demand placed on the system.
There are two main considerations when
deciding when and where a buffer tank
should be used.
1. It may act as an initial boost when a
heating demand is placed on the
system from cold.
2. Storing water for this function will
result in heat losses from the buffer
over time, reducing the overall COP
and therefore the overall efficiency of
the heat pump and the system.
Cylinder
Stat
HW
Flow
Heat Pump
ATC
Outside
wall
Flow
Buffer
tank
Isolating
valve
Cylinder
Stat
Flexible
pipe
Isolating
valve
Return
When considering the use of a buffer,
also consider the space the buffer will
take up – it may not be possible to
house both a cylinder and a buffer tank.
The following diagrams show both an
S-Plan and an extended S-Plan for use
with a buffer tank.
!
When using a buffer tank with the
heat pump, the weather
compensation function of the built-in
BTC controller is NOT used.
A cylinder thermostat (with
immersion probe) should be fitted to
the buffer tank. This must be wired
to switch between terminals 1 & 3
(the Common and HW terminals) on
the S-Plan controls terminal block in
the heat pump control panel. Refer
to Figure 8.15 in Section 8 for wiring
diagram. The BTC setting for 'DHW
BOIL TARGET' should be set to 48˚C.
Internal wiring
centre
Programmer
Room
Stat
Heating Load
NOTE