5 Preparation
Installer reference guide
10
07C2V3
ROTEX HPSU monobloc compact outdoor unit
4P501827-1 – 2017.08
20
2,4
2,1
1,8
1,5
1,2
0,9
1
0,6
0,3
70
120
170
150
105
185
220
270
A
B
A
Pre-pressure (bar)
B
Maximum water volume (l)
Water
Water + glycol
Example: Maximum water volume and expansion vessel pre-
pressure
Installation
height
difference
(a)
Water volume
≤185/105 l
(b)
>185/105 l
(b)
≤7 m
No pre-pressure
adjustment is required.
Do the following:
▪ Decrease
the
pre-
pressure according to
the required installation
height difference. The
pre-pressure
should
decrease by 0.1 bar for
each metre below 7 m.
▪ Check if the water
volume
does
NOT
exceed the maximum
allowed water volume.
>7 m
Do the following:
▪ Increase
the
pre-
pressure according to
the
required
installation
height
difference. The pre-
pressure
should
increase by 0.1 bar for
each metre above 7 m.
▪ Check if the water
volume
does
NOT
exceed the maximum
allowed water volume.
The expansion vessel of
the outdoor 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 outdoor unit. If the outdoor unit
is at the highest point of the installation, the installation
height is 0 m.
(b)
The maximum water volume is 185 l in case the circuit is
only filled with water, and 105 l in case the circuit is filled
with water and glycol.
Minimum flow rate
Check that the minimum flow rate (required during defrost/backup
heater operation) in the installation is guaranteed in all conditions.
NOTICE
If glycol was added to the water circuit, and the
temperature of the water circuit is low, the flow rate will
NOT be displayed on the user interface. In this case, the
minimum flow rate can be checked by way of the pump
test (check that the user interface does NOT display error
7H).
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 or operation).
Minimum required flow rate
05+07 models
13 l/min
See the recommended procedure as described in the installation
manual of the HPSU monobloc tank.
5.3.4
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 Schrader
valve of the expansion vessel.
a
a
Schrader valve
5.3.5
To check the water volume: Examples
Example 1
The outdoor 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 outdoor unit is installed at the highest point in the water circuit.
The total water volume in the water circuit is 350 l. The concentration
of propylene glycol is 35%.
Actions:
▪ Because the total water volume (350 l) is more than the default
water volume (105 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 150 l.
(See the graph in the chapter above).
