Product Description; Product Design - Vaillant flexoTHERM exclusive VWF 57/4 Nstallation And Maintenance Instructions

4 Product description

sible shortage of fluid. If the fluid pressure falls below the
minimum pressure, an analogue pressure sensor switches
off the heat pump and switches the other modules, where
these exist, to standby mode. The pressure sensor switches
the heat pump on again if the fluid pressure reaches the op-
erating pressure.
– Minimum brine fluid pressure: ≥ 0.05 MPa (≥ 0.50 bar)
– Min. brine fluid operating pressure: ≥ 0.07 MPa
(≥ 0.70 bar)
3.3.4 Freeze protection
This function prevents the evaporator from freezing when the
heat source temperature drops below a certain value.
The outlet temperature of the heat source is constantly
measured. If the outlet temperature of the heat source falls
below a certain value, the compressor temporarily switches
off and displays a status message. If this fault occurs three
times in a row, it is switched off and a fault message is
displayed.
3.3.5 Pump- and valve-blocking protection
system
This function prevents the pumps for heating water and
brine and all diverter valves from sticking. The pumps and
the valves, which were out of operation for 23 hours, are
switched on for 10 - 20 seconds, one after the other.
3.3.6 High-pressure pressure switch in the
refrigerant circuit
The high-pressure pressure switch shuts down the heat
pump if the pressure in the refrigerant circuit is too high. Fol-
lowing a waiting period, the heat pump attempts to start once
more. After three failed start attempts in succession, a fault
message is displayed.
–
Max. refrigerant circuit pressure: 4.60 MPa (g) (46.00 bar
(g))
–
Waiting period: 5 minutes (after the first occurrence)
–
Waiting period: 30 minutes
(after the second and every further occurrence)
The fault counter is reset if both of the following conditions
are met:
–
Heat requirement without switching off prematurely
–
60 minutes of uninterrupted operation
3.3.7 Hot gas thermostat in the refrigerant circuit
The hot gas thermostat shuts down the heat pump if the tem-
perature in the refrigerant circuit is too high. Following a wait-
ing period, the heat pump attempts to start once more. After
three failed start attempts in succession, a fault message is
displayed.
– Max. refrigerant circuit temperature: 135 ℃
–
Waiting period: 5 minutes (after the first occurrence)
–
Waiting period: 30 minutes
(after the second and every further occurrence)
The fault counter is reset if both of the following conditions
are met:
–
Heat requirement without switching off prematurely
–
60 minutes of uninterrupted operation
10
3.3.8 Safety cut-out (SCO) in the heating circuit
If the temperature in the heating circuit of the internal elec-
tric back-up heater exceeds the maximum temperature, the
safety cut-out shuts down the electric back-up heater as a
securing measure. Following a waiting period, another at-
tempt is made to start the electric back-up heater. A fault
message is displayed that can only be reset by pressing the
Reset button or by switching the heat pump off and on again.
– Max. heating circuit temperature: 85 ℃
4 Product description
4.1

Product design

4.1.1 Front view, open
4
3
1 Electronics box
2 Control panel
Installation and maintenance instructions flexoTHERM exclusive 0020196687_03
1
2
3 Heating/cylinder char-
ging diverter valve
4 4-port valve