Vaillant geoTHERM Installation Instructions Manual page 106

11 Fault diagnosis and rectification
Fault code Error text/description
94 Phase loss. Check fuse
One or more phases have
failed
95 Incorrect compressor
direction of rotation
Correct the phase
sequence
Phase sequence incorrect
96 Coolant circuit pressure
sensor fault
short-circuit in the pres-
sure sensor
11.4 Fault with permanent switch-off
106
Emergency
Possible cause
mode
possible Loss of a phase or a fuse has
tripped.
Badly tightened electrical con-
nections.
Mains voltage too low.
Energy supply company switch-
off to incorrectly set electric wir-
ing diagram (e. g. Electric Wiring
Diagram 1).
In-rush current limiter faulty or
incorrectly connected.
possible No voltage (temporary switch-off
by energy supply company)
Phases switched over.
In-rush current limiter faulty or
incorrectly connected.
possible A pressure sensor in the coolant
circuit is faulty or not properly
plugged in.
Solution
> Check fuses and cable connections
(power supply to the compressor).
> Check electrical connections.
> Measure voltage at heat pump termi-
nal box.
> Check the setting of the wiring dia-
gram.
> Check the in-rush current limiter and
inform the factory customer service
department if necessary.
> Connect the contact of the ripple con-
trol receiver to terminal 13.
> Change the phase sequence by
switching over 2 phases at a time on
the mains feed.
> Check the in-rush current limiter and
inform the factory customer service
department if necessary.
> Check the quality of plug contact on
the circuit board and on the cable har-
ness.
> Check the pressure sensor for correct
operation.
> Replace the pressure sensor.
Installation instructions geoTHERM 0020051574_04