REMKO SuperTec-Monitor - Manual (Page 26)

Fault code Meaning Cause Remedial measures
U2
Refrigerant level
Incorrect if the hot gas
overheating in cooling mode
TH4–TH5 / in heating mode
TH4–TH6 rises as follows.
All conditions must be fulfilled
for a period of 10 mins (at least
6 mins after the condenser
starts up)!
The condenser is working in
heating mode.
The hot gas overheating is 70°C
or more. TH6 > TH7 – 5K
TH5 < 35°C
The condenser is working
(C/H).
In cooling mode the hot gas
overheating is 80°C or more.
In heating mode the hot gas
overheating is 90°C or more.
In cooling mode the
condensation temperature is
TH6 < –40°C
Rise in temperature in the
condenser due to lack of
refrigerant.
Defective temperature sensor
TH4, TH5, TH6.
Control board of the outdoor
unit defective.
Faulty LEV.
Check inlet overheating.
Check pipework, refrigerant level
and additional fill amount.
Switch supply voltage off and
back on again once. Check
if fault code "U3" is then
displayed. If so, see "Remedial
measures" for "U3".
Check LEV.
U3
Open circuit/short-circuit on
the hot gas temperature sensor
TH4 or condenser temperature
sensor TH32
If no resistance (0°C = 0 Ω) or
infinite resistance (>217°C = ∞
Ω) is measured on the hot gas
temperature sensor TH4 when
the condenser is operational,
fault message "U3" is issued
(this function is not available in
the first 5 to 10 mins after the
condenser begins operation,
after the conclusion of defrost
mode or while defrost mode is
operational.)
Poor or detached contacts of
the cables and connectors on
the control board.
Temperature sensor defective.
Control board of the outdoor
unit defective.
Check connectors and contacts
of the temperature sensor on the
control board and repair.
Check connection cables of the
temperature sensor for cable
break or similar.
Check the temperature sensor
with the help of the system
monitor and proceed accordingly
in order to rectify the fault.
Replace defective control board
of the outdoor unit.
REMKO SYSTEM MONITOR
FOR REMKO SUPERTEC INVERTER
26