Page 8
Section 3: Installation
ISOLATION VALVES
Two 28mm isolating valves are supplied with the volumiser/
header. One of these must be fitted in the system flow pipe and
the other in the system return pipe, close to where they are
connected to the header/volumiser.
FLOW REGULATOR
A flow regulator is supplied with the heat pump. This must be fitted
in the return pipe from the volumiser/header to the heat pump.
Refer to Figure 3-3.
The flow regulator can be fitted vertically or horizontally but must
be installed such that the arrow on the brass body points in the
direction of flow.
For an accurate and stable reading, ensure that there is straight
pipe of at least 5 times the pipe diameter (i.e. for 28mm pipe: 5 x
28mm = 140mm) before the inlet to the regulating valve.
During system commissioning, the flow regulator must be set to
the achieve the required flow rate in the primary circuit between
the heat pump and the volumiser/header.
The required flow rate will be dependent on the required
heat pump output (at design conditions) and the temperature
differential between the heat pump flow and return.
This flow rate can be calculated as follows:
Flow rate = Heat output (kW) ÷ Temperature differential (K)
÷ Specific heat capacity of water (4.2kJ/kgK) *
Example:
Heat output = 12kW
Differential = 5K
Specific heat capacity of water = 4.2 kJ/KgK
Flow rate = 12 ÷ 5 ÷ 4.2 = 0.571 kg/sec
= 0.571 x 60 = 34.3 kg/min (or 34.3 litres/min)
! NOTE !
* The use of an antifreeze/inhibitor/biocide fluid will alter
the value of Specific Heat Capacity but, as the difference is
minimal, use 4.2kJ/kgK as a constant for the calculation of
flow rate.
To set the flowrate, the system should be set to maximum
demand, i.e. with all emitters and zone valves open. The flow rate
is then adjusted by rotating the regulating valve until the required
flow rate is indicated on the flow regulator scale.
•
To increase the flow rate - rotate valve anticlockwise
•
To decrease the flow rate - rotate valve clockwise
The actual flowrate must be read from the LOWER edge of the
float, in the flow regulator window. Refer to Figure 3-3.
If two heat pumps of the SAME output are connected to the low
loss header/volumiser, both flow regulators should be set to the
SAME flowrate, as calculated for the output of each heat pump.
If the two heat pumps are of DIFFERENT outputs:
a)
Calculate the required flow rate for each heat pump, based
on their respective outputs.
b)
Set the flow rate of each heat pump separately, i.e. with only
one heat pump operating at a time.
Figure 3-3:
Flow regulator adjustment
Grant Aerona³ heat pumps are supplied with the circulating pumps
set to the highest of three possible performance curves. In order
to achieve the required flow rate it may be necessary to select
one of the other pump performance curves.
This is done by adjusting the setting of DIP switches DIP SW5
and DIP SW6 on the Terminal PCB of the heat pump. Follow the
guidance given in Section 8.3.6 of the Grant Aerona³ Installation
and Servicing instructions supplied with the heat pump
3.8
SYSTEM CONNECTIONS
The heating system flow and return connections can be made
to either the right-hand or left-hand connections of the Grant
Combined volumiser/low loss header, but BOTH connections
must be made to the opposite side of the volumiser/header to
the heat pump connections. Refer to Figures 3-1 and 3-2 for
connection details.
A second pair of system flow and return connections, i.e. for a
second zone, can also be connected to the volumiser/header,
but must be connected to the same side as the other system
connections. Refer to Figures 3-1 and 3-2 for connection details.
3.9
VOLUMISER ONLY CONNECTIONS
It is possible, if required, to use the Grant Combined volumiser/
low loss header as a volumiser only, either using the integral 3kW
immersion as a supplementary heater or not.
The volumiser/header must be fitted in the flow pipe from the heat
pump as follows:
•
The flow pipe from the heat pump should be connected to
lowest connection on either the right-hand or left-hand side of
the volumiser/header.
•
The outlet pipe from the volumiser/header should be
connected should be connected to one of the upper set of
connections on either the right-hand or left-hand side of the
volumiser/header.
Refer to Figure 3-4.
