Vaillant flexoTHERM exclusive VWF 57/4 230V Installation And Maintenance Instructions Manual Download Page 47

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0020213395_04 Installation and maintenance instructions

Code

Meaning

Cause

Remedy

F.710

Env. circuit: Outlet temp. too low

–

Environment circuit pump defective

–

Temperature sensor for environment
circuit outlet defective

–

Volume flow too low in the environ-
ment circuit

–

Air in the environment circuit

–

Device Specific Number (DSN) set-
ting was not applied when replacing
the control PCB (HMU)

–

Freeze protection setting was not
applied when replacing the control
PCB (HMU)

–

Check the flow rate in the environ-
ment circuit

–

Check the quality of the plug contact
on the PCB and on the cable har-
ness

–

Check that the sensor is working
correctly (resistance measurement
using sensor characteristic values)

–

Replace the sensor

–

Check the volume flow of the en-
vironment circuit pump (optimum
spread of 3 K)

–

Purge the environment circuit

–

Always check the Device Specific
Number (DSN) setting

–

Check the set value for the freeze
protection in accordance with the en-
vironment circuit type on the control
panel

F.714

Environment circuit: Pressure too
low

–

Pressure loss in the environment
circuit due to leakages or air pockets

–

Environment circuit pressure sensor
defective

–

Check the environment circuit for
leaks

–

Top up the medium (brine-to-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

F.715

Env. circuit: Fault contact: Pump
open

–

The electronics system of the high-
efficiency pump has detected a fault
(e.g. dry running, blockage, dirt,
overvoltage, undervoltage) and has
switched off and locked the pump.

–

Air in the environment circuit

–

Brine fluid viscosity is too high

–

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

–

Purge the environment circuit

–

Use a refractometer to check the
mixture ratio of the brine fluid

–

Check the dirt filter/strainer for dirt

–

Check the air separator

F.718

Fan unit 1: Fan blocked

–

There is no confirmation signal stat-
ing that the fan is rotating

–

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)

F.719

Fan unit 1: Safety cut-out open

–

The safety cut-out on the de-icer is
open due to insufficient volume flow
and/or brine temperatures above
70 °C

–

When operating the de-icer outside
of the permitted area of application

–

De-icer operation when the brine
circuit is not filled

–

De-icer operation at brine tem-
peratures above 120 °C trips the
safety fuse of the safety cut-out
and requires that the fuse be re-
placed

–

Check for circulation in the environ-
ment circuit pump

–

If required, open the stopcocks

The safety cut-out is automatically reset
as soon as the temperature at the fuse
falls below 55 °C again.
If the safety cut-out is still open at a de-
icer temperature below 55 °C, temper-
atures above 120 °C were reached and
the safety fuse tripped.

–

Check and, if required, replace the
F1 fuse of the air/brine collector

–

Replace the safety cut-out

F.723

Building circuit: Pressure too low

–

Pressure loss in the building circuit
due to leakages or air pockets

–

Building circuit pressure sensor de-
fective

–

Check the building circuit for leaks