6 Preparation
Installer reference guide
26
RRLQ004~008CA + RHBH/X04+08CB
ROTEX HPSU low temperature Bi‑bloc
4P384979-1 – 2015.01
0.3
0.5
1
1.5
2
2.5
100
50
0
10
150
200
250
300
350
400
450
a
b
a
Pre-pressure (bar)
b
Maximum water volume (l)
Example: Maximum water volume and expansion vessel pre-
pressure
Installation
height
difference
(a)
Water volume
≤280 l
>280 l
≤7 m
No pre-pressure
adjustment is required.
Do the following:
▪ Decrease
the
pre-
pressure.
▪ Check if the water
volume
does
NOT
exceed the maximum
allowed water volume.
>7 m
Do the following:
▪ Increase
the
pre-
pressure.
▪ Check if the water
volume
does
NOT
exceed the maximum
allowed water volume.
The expansion vessel of
the indoor unit is too
small for the installation.
In this case, it is
recommended to install
an extra vessel outside
the unit.
(a)
This is the height difference (m) between the highest point
of the water circuit and the indoor unit. If the indoor unit is
at the highest point of the installation, the installation height
is 0 m.
Minimum flow rate
Check that the minimum flow rate (required during defrost/backup
heater operation) in the installation is guaranteed in all conditions.
NOTICE
When circulation in each or certain space heating loops is
controlled by remotely controlled valves, it is important that
the minimum flow rate is guaranteed, even if all valves are
closed. In case the minimum flow rate cannot be reached,
a flow error 7H will be generated (no heating/operation).
Minimum required flow rate during defrost/backup heater
operation
04+08 models
12 l/min
11+16 models
15 l/min
See the recommended procedure as described in
during commissioning" on page 72
6.4.4
Changing the pre-pressure of the
expansion vessel
NOTICE
Only a licensed installer may adjust the pre-pressure of the
expansion vessel.
When changing the default pre-pressure of the expansion vessel
(1 bar) is required, take following guidelines into account:
▪ Only use dry nitrogen to set the expansion vessel pre-pressure.
▪ Inappropriate setting of the expansion vessel pre-pressure will
lead to malfunction of the system.
Changing the pre-pressure of the expansion vessel should be done
by releasing or increasing nitrogen pressure through the schräder
valve of the expansion vessel.
a
a
Schräder valve
6.4.5
To check the water volume: Examples
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.
No actions or adjustments are 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 350 l.
Actions:
▪ Because the total water volume (350 l) is more than the default
water volume (280 l), the pre-pressure must be decreased.
▪ The required pre-pressure is:
Pg = (0.3+(H/10)) bar = (0.3+(0/10)) bar=0.3 bar.
▪ The corresponding maximum water volume at 0.3 bar is 410 l.
(See the graph in the chapter above).
▪ Because 350 l is lower than 410 l, the expansion vessel is
appropriate for the installation.
6.5
Preparing electrical wiring
6.5.1
About preparing electrical wiring
INFORMATION
Also read the precautions and requirements in the
"General safety precautions" chapter.
