Vaillant flexoTHERM exclusive VWF 117/4 Installation And Maintenance Instructions Manual page 50

Appendix
Code Meaning
F.715 Env. circuit: Fault contact: Pump
open
F.718 Fan unit 1: Fan blocked
F.719 Fan unit 1: Safety cut-out open
F.723 Building circuit: Pressure too low
F.724 Sensor fault: Fan unit 1 fan inlet
temp.
F.725 Sensor fault: Fan unit 1 brine flow
temp.
F.731 High pressure switch opened
F.732 Compressor outlet temperature
too high
50
Cause
–
The electronics system of the high-
efficiency pump has detected a
fault (e. g. dry running, blockage,
overvoltage, undervoltage) and
switched the pump off as a securing
measure.
–
There is no confirmation signal stat-
ing that the fan is rotating
–
The safety cut-out on the de-icer is
open due to insufficient volume flow
and/or brine temperatures above
65 °C
–
Operating the de-icer outside of the
permitted area of application
–
De-icer operation when the brine
circuit is not filled
–
During de-icer operation at brine
temperatures above 115 °C, the fuse
of the safety cut-out is tripped and
the fuse must be replaced.
–
Pressure loss in the building circuit
due to leaks or air pockets
–
Building circuit pressure sensor
defective
–
Sensor not connected or sensor
input has short-circuited
–
Sensor not connected or sensor
input has short-circuited
–
Coolant pressure too high. The
integrated high-pressure switch has
tripped at 46 bar (g) or 47 bar (abs)
–
Insufficient energy output via the
relevant condenser
The compressor outlet temperature is
above 130 °C:
–
Application limits exceeded
–
EEV does not work or does not open
correctly
–
Coolant volume too low
Installation and maintenance instructions flexoTHERM exclusive 0020213394_01
Remedy
–
Switch the heat pump off for at least
30 seconds (no current)
–
Check the quality of the plug contact
on the PCB
–
Check that the pump functions cor-
rectly
–
Purging the environment circuit
–
Check the air route and, if required,
remove any blockages
–
Check and, if required, replace the
F1 fuse on the PCB in the fan unit
(OMU)
–
Checking for circulation in the envir-
onment circuit pump
–
If required, open the stop cock. The
safety cut-out is automatically reset
as soon as the temperature at the
fuse falls below 30 °C again. If the
safety cut-out is still open at a de-
icer temperature below 65 °C (or
30 °C), temperatures above 115 °C
were reached and the fuse tripped.
–
Check and, if required, replace the
F1 fuse of the air/brine collector
–
Replace the safety cut-out
–
Check the building circuit for leaks
–
Top up with water, purge
–
Check the quality of the plug contact
on the PCB and on the cable har-
ness
–
Check that the pressure sensor is
working correctly
–
Replace the pressure sensor
–
Check the sensor in the fan unit, and
replace if necessary
–
Replace the cable harness in the fan
unit
–
Check the sensor in the fan unit, and
replace if necessary
–
Replace the cable harness in the fan
unit
–
Purging the building circuit
–
Insufficient volume flow as a result of
closing individual room controllers 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,
four-way valve mechanically blocked,
filter blocked). Inform Customer
Service.
–
VWL SA (cooling mode): Check the
fan unit for dirt
–
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