48
Installation and maintenance instructions 0020213395_04
Code
Meaning
Cause
Remedy
F.724
Sensor fault: Fan unit 1 fan inlet
temp.
–
Sensor not connected or sensor in-
put has short-circuited
–
Check the sensor in the fan unit, and
replace if necessary
–
Replace the cable harness in the fan
unit
F.725
Sensor fault: Fan unit 1 brine flow
temp.
F.731
High-pressure switch open
–
Refrigerant pressure too high. The
integrated high-pressure switch has
tripped at 46 bar (g) or 47 bar (abs)
–
Insufficient energy output via the
relevant capacitors
–
Purging the building circuit
–
Too low a volume flow as a result
of closing single room controls in an
underfloor heating system
–
Check that the dirt filter that is in
place is permeable
–
Refrigerant flow rate too low (e.g.
electronic expansion valve defective,
4-port valve mechanically blocked,
filter blocked). Inform customer ser-
vice.
–
VWL SA (cooling mode): Check the
fan unit for dirt
F.732
Compressor outlet temperature
too high
The compressor outlet temperature is
above 130 °C:
–
Application limits exceeded
–
EEV does not work or does not open
correctly
–
Refrigerant volume too low
–
Check the low-pressure sensor,
compressor inlet sensor and outlet
sensor
–
Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
–
Check the refrigerant volume (see
Technical data)
–
Carry out a leak-tightness test
F.733
Evaporation temperature too low
–
No flow rate in the environment cir-
cuit (heating mode)
–
Energy input too low in the environ-
ment circuit (heating mode) or build-
ing circuit (cooling mode)
–
Check the flow rate in the environ-
ment circuit
–
Check the dimensioning of the en-
vironment circuit (heating mode) for
ground/brine and ground water/brine
–
If the building circuit contains ther-
mostatic valves, check that they are
suitable for cooling mode (cooling
mode)
–
VWL_SA (heating mode)
–
Check the fan unit for dirt
–
Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
–
Check the low-pressure sensor and
compressor inlet sensor
F.734
Condensation temperature too low
–
Temperature in the building circuit
(heating mode) or environment cir-
cuit (cooling mode) too low for com-
pressor operation
–
Refrigerant volume too low
–
Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
–
Check the compressor inlet sensor,
high-pressure sensor and low-pres-
sure sensor
–
Check the refrigerant volume (see
Technical data)
–
Leak-tightness test
F.735
Evaporation temperature too high
–
Temperature in the environment cir-
cuit (heating mode) or building cir-
cuit (cooling mode) too high for com-
pressor operation
–
Feed-in of external heat into the en-
vironment circuit
–
Reduce or stop the external heat
that is entering
–
Check the de-icer (does it heat
up even though it is
Off
in the
sensor/actuator test?)
–
Check the EEV (does the EEV
move to the limit stop? Use the
sensor/actuator test)
–
Check the compressor inlet sensor
and low-pressure sensor
Summary of Contents for flexoTHERM exclusive VWF 57/4 230V
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