E(D/B)(H/L)Q011~016BB
Unit for air to water heat pump system
4PW67904-1 – 01.2011
Installation manual
18
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 unit is too small
for the installation.
figure "Maximum allowed water volume"
Example 1
The 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 unit is installed at the highest point in the water circuit. The total
water volume in the water circuit (no glycol used) is 350 l.
Result:
■
Since 350 l is higher than 280 l, the pre-pressure must be
decreased (see table above).
■
The required pre-pressure is:
Pg=(H/10+0.3) bar=(0/10+0.3) bar=0.3 bar
■
The corresponding maximum water volume can be read from
the graph: approximately 410 l.
■
Since the total water volume (350 l) is below the maximum water
volume (410 l), the expansion vessel suffices for the installation.
Setting the pre-pressure of the expansion vessel
When it is required to change the default pre-pressure of the
expansion vessel (1 bar), keep in mind the following guidelines:
■
Use only dry nitrogen to set the expansion vessel pre-pressure.
■
Inappropriate setting of the expansion vessel pre-pressure will
lead to malfunction of the system. Therefore, the pre-pressure
should only be adjusted by an installer.
Connecting the water circuit
Water connections must be made in accordance with the applicable
legislation and the outlook diagram delivered with the unit, respecting
the water in- and outlet.
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 Unit
2 Heat exchanger
3 Backup heater
(a)
4 Pump
5 Shut-off valve
6 Collector (field supply)
7 By-pass valve (field supply)
FHL1...3 Floor heating loop (field supply)
T1...3 Individual room thermostat (optional)
M1...3 Individual motorised valve to control loop
FHL1...3 (field supply)
UI User interface
(a) For tank without electrical booster heater (EKHTS), the backup heater will be
used in domestic water heating mode.
Installation
height
difference
(a)
(a) Installation height difference: height difference (m) between the highest point of
the water circuit and the unit. If the 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.
FHL1
FHL2
FHL3
M1
T1
M2
T2
M3
T3
4
2
3
1
6
7
UI
5
pre-pressure
= pre-pressure
maximum water volume
= maximum water volume
A
= System without glycol
B
= System with 25% propylene glycol
(Refer to
"Caution: "Use of glycol"" on page 19
)
NOTICE
Be careful not to deform the unit piping by using excessive
force when connecting the piping. Deformation of the
piping can cause the unit to malfunction.
0.3
0.5
1
1.5
2
2.5
100
50
0
20
150
200
250
300
350
400
450
[l]
maximum water volume
[bar]
pre-pressure
B
A
