Safety Devices - Vaillant flexoTHERM exclusive VWF 57/4 Installation And Maintenance Instructions Manual

3.2.2 Weather-controlled system controller
The heat pump system is equipped with a weather-controlled
system controller that provides heating, cooling and hot wa-
ter handling depending on the control type and controls this
in automatic mode.
The controller changes the target flow temperature based on
the outside temperature. The outside temperature is meas-
ured by a separate sensor which is mounted in the open air,
and the results are transmitted to the controller. The room
temperature depends only on the preset values. The system
compensates for the effect of the outside temperature. Hot
water generation is not affected by the weather compensa-
tion. The instructions for the system controller describe how
to install and operate the product.
3.3

Safety devices

3.3.1 Frost protection function
The frost protection function for the system is controlled via
the system controller. If the system controller fails, the heat
pump guarantees limited frost protection for the heating cir-
cuit.
3.3.2 Protection against low heating water
pressure
This function continuously monitors the pressure of the heat-
ing water in order to prevent a possible loss of heating water.
If the water 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. It switches the heat pump on again if the water pres-
sure reaches the operating pressure.
– Min. heating circuit pressure: ≥ 0.05 MPa (≥ 0.50 bar)
– Min. heating circuit operating pressure: ≥ 0.07 MPa
(≥ 0.70 bar)
3.3.3 Brine loss protection system
The brine loss protection system continuously monitors the
fluid pressure in the environment circuit in order to prevent a
possible 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. It switches the heat pump on
again if the fluid pressure reaches the operating 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.
0020213395_00 flexoTHERM exclusive Installation and maintenance instructions
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
refrigeration circuit
The high-pressure pressure switch shuts down the heat
pump if the pressure in the coolant circuit is too high. If the
pressure in the heat pump's refrigeration circuit exceeds
the maximum pressure, the high-pressure pressure switch
temporarily shuts down the heat pump. Following a waiting
period, another attempt is made to start the heat pump. After
three failed start attempts in succession, a fault message is
displayed.
–
Refrigeration circuit pressure max.: 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 refrigeration
circuit
The hot gas thermostat shuts down the heat pump if the tem-
perature in the refrigeration circuit is too high. If the temper-
ature in the heat pump's refrigeration circuit exceeds the
maximum temperature, the hot gas thermostat temporar-
ily shuts down the heat pump. Following a waiting period,
another attempt is made to start the heat pump. After three
failed start attempts in succession, a fault message is dis-
played.
– Max. refrigeration 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
3.3.8 Safety cut-out (SCO) in the heating circuit
If the temperature in the heating circuit of the internal auxili-
ary electric heating exceeds the maximum temperature, the
SCO shuts down the auxiliary electric heating as a secur-
ing measure. Following a waiting period, another attempt is
made to start the auxiliary electric heating. A fault message
is displayed that can only be reset by pressing the Reset but-
ton or by switching the heat pump off and on again.
– Max. heating circuit temperature: 85 ℃
System overview 3
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