Vaillant ecoTEC pro VUW 6/5-3 Series, Installation And Maintenance Instructions Manual

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Installation and maintenance instructions ecoTEC pro 0020244995_04
Message Possible cause Measure
F.83 Fault: NTC temp. gradient Temperature difference
between flow and return
temperature sensor is too small
▶
Check: Flow/return temperature sensor (function, correct
thermal connection), sufficient water volume.
F.84 Fault: NTC temp. diff. im-
plausible
Temperature difference is im-
plausible
▶
Check: Flow/return temperature sensor (correct thermal con-
nection, sensors are inverted).
F.85 Fault: NTCs fitted incor-
rectly
Flow/return temperat-
ure sensors returning
incorrect/implausible values
▶
Check: Flow/return temperature sensor (correct thermal con-
nection).
Communication fault Communication fault between
the display and the PCB in the
electronics box
▶
Check: Cable/plug between the display and the PCB.
E Check programmes
–
Overview
Check programme Meaning
P.00 Purging The internal pump is cyclically actuated. The heating circuit and the domestic hot water circuit are ad-
aptively purged by automatically switching the circuits using the automatic air vent (the automatic air
vent's cap must be loose). The active circuit is shown in the display. Press
once to start purging
the heating circuit. Press once to end the purge programme. Note: The purge programme runs for
7.5 min per circuit and then terminates. Purging the heating circuit: Prioritising diverter valve in heat-
ing position, actuation of internal pump for 9 cycles: 30 sec. on, 20 sec. off. Display: Active heating
circuit. Purging the domestic hot water circuit: After the above-mentioned cycles have run or the right-
hand selection button has been pressed again: Prioritising diverter valve in the domestic hot water
position, actuation of the internal pump as above. Display: Active domestic hot water circuit.
P.01 Maximum load After successful ignition, the product is operated at maximum heat input.
P.02 Minimum load After successful ignition, the product is operated at minimum heat input.
P.06 Filling mode The prioritising diverter valve is moved to the mid-position. The burner and pump are switched off (to
fill or drain the product).