Appendix
38
Installation
and
maintenance
instructions
ecoTEC
pro
0020244995_02
Message
Possible cause
Measure
F.77 Fault: Flue non-ret.
valve/condens. pump
No flue non-return flap feed-
back; condensate pump over-
flow
▶
Check: Cable to VR40 accessory, flue non-return flap (wiring,
feedback switch), condensate pump, bridge from the surface-
mounted thermostat, 2 in 7 multi-functional module (bridge).
F.78 Interrupt.: DHW outlet
sensor on ext. contr.
UK link box is connected
without the domestic hot water
temperature sensor being
bridged
1.
Check: Accessory (configuration/electrical connection).
2.
The unit displays a fault, but the unit has not malfunctioned.
F.83 Fault: NTC temp. gradi-
ent
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.
implausible
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.
D
Check programmes
–
Overview
Prüfprogramme
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 flap 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 seconds on, 20 seconds 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 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).
