8.4 - Protection against cavitation
To ensure the durability of the pumps in the integreated hydraulic
modules, the control algorithm of the TD units incorporates anti-
cavitation protection.
It is therefore necessary to ensure a minimum pump entering
pressure of 40 kPa (0.4 bar) during operation and at shut-down.
A pressure below 40 kPa will prohibit unit start-up or cause an
alarm with the unit shutting down. In order to obtain sufficient
pressure, it is recommended:
to pressurise the hydraulic circuit between 1 and 4 bar
(maximum),
to clean the hydraulic circuit before charging water (see chapters
9.2 and 9.3),
to regularly clean the screen filter,
The use of integrated hydraulic kits in the open
loop is not permitted.
Typical hydraulic circuit diagram
11
9
8
2
3
7
5
19
22
17
17
14
15
20
T
P
T
18
1
4
14
17
Opon
21
19
Opon
16
16
5
P
10
6
13
5
6
6
12
12
Opon
Opon
12
Key
Components of the unit and hydraulic module
B
Screen filter (particle size of 1.2 mm)
C
Relief valve
D
Single operating pressure pump
E
Air bleed valve
F
Water drain tap
G
Shut-off valve
H
Pressure sensor
Notes:
- Provides pressure information for the pump inlet (see Control manual)
I
Temperature sensor
Note:
- Provides temperature information for the water type heat exchanger outlet
(see Control manual)
J
Temperature sensor
Note:
- Provides temperature information for the water type heat exchanger inlet
(see Control manual)
K
Pressure sensor
Note:
- Provides pressure information for the water type heat exchanger outlet (see
Control manual)
L
Plate heat exchanger
M
Heater or heat trace cable for antifreeze protection (Option)
N
Water type heat exchanger flow rate sensor
Installation components
O
Temperature probe well
P
Air vent
Q
Flexible connection
R
Shut-off valve
S
Screen filter (obligatory for a unit without hydraulic module)
T
Pressure gauge
U
Water flow control valve (optionnal with hydraulic module option)
V
Charge valve
W
Frost protection bypass valve (when shut-off valves [17] are closed during
winter)
--- Hydraulic module (unit with hydraulic module)
Notes:
•
Units without hydraulic module (standard units) are equipped with a flow switch
and two temperature sensors (7 and 9).
•
For units equipped with hydraulic module, the pressure sensor located upstream
of the pump to prevent cavitation is installed on a connection without Schraeder
valves. Depressurise and drain the system before any intervention.
8 - WATER CONNECTIONS
EN-25 AQUACIAT
CALÉO™
TD
