Message
Possible cause
Remedy
0015 A
T1 ⇞
Inlet temperature too high.
Check operating conditions.
Check all supply lines, inlet silencer and
airend.
Check ambient conditions.
0016 A
T_M ⇞
Drive motor temperature too
high.
Check ambient and operating conditions.
0017 A
dT ⇞
T2/T1 temperature differ‐
ence too high.
Check operating conditions.
Check all supply lines, drainage lines, in‐
let and outlet silencers and airend.
0018 A
Filter blocked
Inlet filter clogged.
Replace inlet filter.
0019 A
FC error %d
Internal fault, frequency con‐
verter.
Contact an authorised service partner.
0020 A
Oil level side B
Lubricant level at airend
control-end too low.
Replenish lubricating oil.
0021 A
External message 1
1)
0022 A
Aftercooler
Current draw of fan motor
too high.
Temperature too high.
Aftercooler clogged.
Check fan
Check operating conditions.
Clean aftercooler.
0023 A
USS bus communication
error
A fault occurred in the data
transmission between con‐
troller and compressor drive
FC.
Contact an authorised service partner.
0024 A
Diagnostics group alarm
A diagnostic message has
been triggered.
For more details, see diagnostic mes‐
sage text.
Contact an authorised service partner.
0025 A
T3 ⇞
Oil temperature very high
Check ambient and operating conditions.
0026 A
π=p2_a/p1_a ⇞
Pressure ratio across airend
too high – Alarm
Inlet conditions (pressure) or back pres‐
sure too high -
Check filter.
Check position of process valves.
0027 A
T1 ⇟
Inlet temperature too low –
Alarm T1 very low
Check inlet conditions (piping, room) -
Check ambient and operating conditions.
0028 A
Error USS handler %d
Blower USS bus fault
Check connection and line path.
0029 A
PKW requests
failed %d %d
USS communication inter‐
rupted
Check connection and line path.
0030 A
Error FC ramp up
Error while activating FC
Contact an authorised service partner.
0031 A
Motor: n min not reached
Frequency converter fault
Contact an authorised service partner.
10 Fault Recognition and Rectification
10.2 Interpreting alarm messages
158
Service Manual Controller
SIGMA CONTROL 2 BLOWER ≥ 4.0.X
No.: 901700 14 E
