User operation
16
MAXXfl o EVO Lite
3.8.1 Error codes
Error
Code
Error Code
Description
Diag.
Code
Notes
20
Boiler tempera-
ture 1, sensor
error
Other
Water heater fl ow sensor (B2) is outside normal limits
439
Water heater fl ow sensor (B2) is short-circuit. Check connection for possible con-
tamination or faulty sensor.
440
Water heater fl ow sensor (B2) is open-circuit. Check connection for possible con-
tamination or faulty sensor.
28
Flue gas tem-
perature, sensor
error
539
543
Flue gas sensor (B8) is short-circuit. Check connection for possible contamination
or faulty sensor.
540
544
Flue gas sensor (B8) is open-circuit. Check connection for possible contamination
or faulty sensor.
40
Return tempera-
ture 1, sensor
error
Other
Water heater return sensor (B7) is outside normal limits
441
Water heater return sensor (B7) is short-circuit
442
Water heater return sensor (B7) is open-circuit
50
DHW tempera-
ture 1, sensor
error
55
Check connections or replace faulty DHW tank sensor (B3)
57
DHW circulating
sensor fault
58
Check connections and operation of the strap on return pipe sensor (B39) con-
nected through onto the AGU2.5 expansion module
81
LPB short-circuit
or no power sup-
ply
67
Check external connections onto the LPB terminals are the not shorted and the
correct polarity. Inspect connections from the GUI to the Control PCB.
82
LPB address col-
lision
103
LPB address duplicated on another Siemens controlled appliance. Check ad-
dresses of all Siemens controlled appliances via parameter 6600
83
BSB short circuit
595
No BSB communication or wires shorted - Check operation of GUI or OZW672 (if
fi tted)
84
BSB address col-
lision
104
Two appliances connected through BSB (e.g. OZW672) have the same allocation
address. Change one of the appliances address via parameter 6600
98
Extension mod-
ule 1, error
605
Indicates that an expansion module can no longer be “seen” by the controls. To
clear this message perform a “Store sensors” (parameter 6200) command, to
perform a controls handshake with all connected sensors and ancillaries
NB: When applying power to the heater, this fault message may appear briefl y,
but should self clear within 5 minutes. If message persists perform a “Store sen-
sors” command
100
More than one
clock time master
105
Only one device should be set as the time master, check on the GUI (parameter
6640) and any OZW672 connected (in case of connection to an OZW672, this
device should be the master)
102
Clock master
without power
reserve
106
The control PCB battery backup for the time clock has been depleted following
the restoration of power to the heater. If this message has not cleared within 10
minutes of power being turned on, turn the power off , wait 10 seconds and turn
the power on again. This message does not prevent the operation of the heater in
any way.
105
Maintenance
message
87
Item requiring attention but not preventing appliance operation (e.g. 12 Month
service due). Check details of message on the appliance Front GUI screen.
