Installation manual
11
EKHBRD011~Y1
Indoor unit for air to water heat pump system
4PW54465-1A
Checking the water volume and expansion vessel
pre-pressure
The unit is equipped with an expansion vessel of 12 litre which has a
default pre-pressure of 1 bar.
To assure proper operation of the unit, the pre-pressure of the
expansion vessel might need to be adjusted and the minimum and
maximum water volume must be checked.
1
Check that the total water volume in the installation, excluding
the internal water volume of the unit, is 20 l minimum.
2
Using the table below, determine if the expansion vessel pre-
pressure requires adjustment.
3
Using the table and instructions below, determine if the total
water volume in the installation is below the maximum allowed
water volume.
Calculating the pre-pressure of the expansion vessel
The pre-pressure (Pg) to be set depends on the maximum
installation height difference (H) and is calculated as below:
Pg=(H/10+0.3) bar
Checking the maximum allowed water volume
To determine the maximum allowed water volume in the entire circuit,
proceed as follows:
1
Determine for the calculated pre-pressure (Pg) the
corresponding maximum water volume using the graph below.
2
Check that the total water volume in the entire water circuit is
lower than this value.
If this is not the case, the expansion vessel inside the indoor unit is
too small for the installation.
Example 1
The indoor unit is installed 5 m below the highest point in the water
circuit. The total water volume in the water circuit is 100 l.
In this example, no action or adjustment is required.
Example 2
The indoor unit is installed at the highest point in the water circuit.
The total water volume in the water circuit is 380 l.
In most applications this minimum water volume will have a
satisfying result.
In critical processes or in rooms with a high heat load
though, extra water volume might be required.
When circulation in each space heating/radiator loop is
controlled by remotely controlled valves, it is important that
this minimum water volume is kept even if all the valves are
closed.
Example
1
Outdoor unit
10
Radiator (field supply)
2
Indoor unit
11
Electronic expansion
valve
3
Refrigerant heat
exchanger
C1
Remote controller
4
Water heat exchanger
M1...M3
Individual motorized valve
to control loop radiators
(field supply)
5
Compressor
6
Pump
T1...T3
Individual room
thermostat (field supply)
7
Shut-off valve
8
Collector (field supply)
A
Installation space
9
By-pass valve
(field supply)
B
Living room
7 7 8
4
3
2
9
1
6
10
5
T3
T2
A
B
C1
M3
M2
M1
T1
11
11
Installation
height
difference
(a)
(a) Installation height difference: height difference (m) between the highest
point of the water circuit and the indoor unit. If the indoor unit is located at
the highest point of the installation, the installation height is considered 0 m.
Water volume
65°C
≤
270 l
80°C
≤
180 l
65°C >270 l
80°C >180 l
≤
7 m
No pre-pressure adjustment
required.
Actions required:
• pre-pressure must be
decreased, calculate
according to
"Calculating
the pre-pressure of the
expansion vessel"
• check if the water volume
is lower than maximum
allowed water volume
(use graph below)
>7 m
Actions required:
• pre-pressure must be
increased, calculate
according to
"Calculating
the pre-pressure of the
expansion vessel"
• check if the water volume
is lower than maximum
allowed water volume
(use graph below)
Expansion vessel of the unit
too small for the installation.
= pre-pressure
= maximum water volume
= increase pre-pressure vessel volume
= decrease pre-pressure vessel volume
0.3
0.5
1
0.0
1.5
2
2.5
100
50
0
20
150
200
250
300
350
400
450
maximum water volume [l]
pre-pressure [bar]
80
80
°
C
65
65
°
C
80
°
C
65
°
C
Summary of Contents for EKHBRD011AAV1
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