Daikin EKHBX016BB3V3S, Installation Manual

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EKHBX016BB3V3S
Indoor unit for air to water heat pump system
4PW62598-1 – 10.2010
Installation manual
16
Checking the water volume and expansion vessel
pre-pressure
The unit is equipped with an expansion vessel of 10 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 indoor unit, is 20 l minimum.
Refer to
"12. Technical specifications" on page 50 to know the
internal water volume of the indoor unit.
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.
INFORMATION
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.
NOTICE
When circulation in each space heating 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
2 Indoor unit
3 Heat exchanger
4 Backup heater
5 Pump (field supply)
6 Shut-off valve
7 Collector (field supply)
8 By-pass valve (field supply)
FHL1...3 Floor heating loop
T1...3 Individual room thermostat (optional)
M1...3 Individual motorised valve to control the floor
heating loop (field supply)
FHL1
FHL2
FHL3
M1
T1
M2
T2
M3
T3
8
6 4 5 3 2 1
6
7
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
≤
280 l >280 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 = pre-pressure
maximum water volume = maximum water volume
0.3
0.5
1
1.5
2
2.5
100 50 0
20
150 200 250 300 350 400 450
maximum water volume [l]
pre-pressure [bar]