andrews MAXXflo EVO Lite User manual

Andrews. Built to perform.
Please read and understand these instructions before commencing installation and leave this manual with the customer for future reference.
M10226
MAXXfl o EVO Lite
High effi ciency condensing stainless steel storage water heater
SC15/201, SC25/201, SC35/201, SC45/201
CONTROLS - USER OPERATING INSTRUCTION MANUAL

Contents
1 Safety
1.1 Important safety instructions ..................................................................................
1.2 Recommendations and notices ..............................................................................
2 Introduction to the heater controls
2.1 The Graphical User Interface (GUI) .......................................................................
2.2 Navigate and set using the control knob ................................................................
2.3 Display symbol meanings .....................................................................................
3 User operation
3.1 The home page .....................................................................................................
3.2 Setting the time and date ......................................................................................
3.3 Setting DHW operating mode .............................................................................
3.4 Setting DHW temperature .....................................................................................
3.5 Setting DHW heating time program ......................................................................
3.6 Temporary DHW operation function ......................................................................
3.7 Information pages .................................................................................................
3.8 Error messages .....................................................................................................
3.8.1 Error codes ...............................................................................................
3.9 Maintenance messages ........................................................................................
3.10 Regional settings ................................................................................................
4 Commissioning operation (in addition to User operation)
4.1 Logging into commissioning mode .........................................................................
4.2 Input / Output test .................................................................................................
4.3 Communication .....................................................................................................
4.4 Source ..................................................................................................................
4.5 Consumer .............................................................................................................
4.6 Versions ...............................................................................................................
3
4
6
7
8
9
9
10
10
11
13
14
15
16
20
21
22
23
24
25
26
27

Safety 3 MAXXfl o EVO Lite
1 Safety
1.1 Important safety instructions
Danger
If you smell gas:
1. Do not use naked fl ames, do not smoke and do not operate
electrical contacts or switches (lighting, motor, lift etc) 2. Shut
off the gas supply
3. Open the windows
4. Trace possible leaks and seal them off immediately
5. If the leak is upstream of the gas meter, notify the gas sup-
plier.
Danger
Danger to life.
Observe warnings affi xed to this heater. Incorrect operation
of this heater could lead to considerable damage.
Danger
Risk of poisoning:
Never use condensate as drinking water. Condensate is not
suitable for consumption by people or animals. Avoid contact
with skin.
Danger
This heater is not intended for use by persons under the age
of 12, or persons with reduced physical, sensory or mental
capabilities, lack of experience or knowledge. Only users given
supervision or instruction concerning the safe operation of this
heater and understand the hazards involved should be operat-
ing this appliance. Children should be supervised to ensure
that they do not play with the heater.
Danger
Unauthorised conversions and modifi cations to this heater are
not permitted, as these can put persons in danger and could
cause damage to the boiler. Failure to comply with these in-
structions renders the warrantee for the heater void
Danger
Do not store any explosive or highly fl ammable materials
close to the heater
Warning
Risk of burns!
Be careful when using domestic hot water. Depending on the
heater settings the temperature of the hot water can rise above
65OC.
For safety reasons the discharge pipe from the safety valve
must always be open so that water can escape during an
emergency overheat situation.

Safety 4 MAXXfl o EVO Lite
1.2 Recommendations and notices
Caution
Ensure that the heater is regularly serviced. Contact a quali-
fi ed installer/engineer or arrange a maintenance contract for
the servicing of the heater.
Caution
Secure against unintentional switch on. When the DHW
tank is empty, ensure that the heater cannot be switched on
unintentionally.
Caution If there is a danger of freezing do not shut the
gas supply or power off to the heater. This will allow the
frost protection systems of the heater to operate provided
the heater is not in a fault condition.
1.2.1 Condensate trap
To ensure continued effi cient operation of the heater it is recom-
mended that the condensate outlet is checked and serviced at
regular intervals. The frequency of servicing will depend upon the
particular installation and usage but in every case a maximum of
twelve months should be allowed between service inspections.
The condensate outlet shall not be modifi ed or blocked. It is recom-
mended that as part of the regular maintenance the condensate
systems is examined, cleaned and the condensate trap on the side
of the heater is emptied and cleaned. The trap can be examined by
unscrewing by hand the bowl at the bottom of the trap. See illustra-
tion
1.2.2 Heater installation and Maintenance
This heater has been designed for use with G20 and G31 gases and
is manufactured to give an effi cient, safe and long service life. To
ensure continued trouble-free operation of this heater at maximum
effi ciency, it is essential that correct installation, commissioning,
operation and service procedures are carried out strictly in accord-
ance with the instructions given in the “Installation & Maintenance
Manual” supplied separately to this guide.
Only original parts and accessories from the manufacturer may be
used on this heater. Using non-approved parts may compromise the
safety of the heater and invalidate any warranty.

Safety 5 MAXXfl o EVO Lite
1.2.3 Regulations and standards
It is the law that all gas heaters are installed by a competent person in
accordance with the regulations. Failure to install or maintain heaters
correctly could lead to prosecution.
It is in your own interest, and that of safety, to ensure that the law is
complied with. The installation of the Heater MUST also be in accord-
ance with the current wiring regulations, the Local building regula-
tions, building standards, the bye laws of the local water undertaking,
any relevant requirements of the local authority.
A detailed guide to the Installation and maintenance of this
heater is supplied separately (Installation and Maintenance
Manual) and this is intended for use by the specialist com-
mercial installers and service engineers.
1.2.4 Frost protection
This heater is fi tted with an automatic Frost Protection system. Pro-
vided there is electrical power, gas is connected and the heater is
not in a lockout condition, this system will be eff ective in preventing
damage to the heater caused by frozen water. This protection will be
active even when the controls are in the standby operation mode.
If the temperature of the Domestic Hot Water tank should fall below
5OC heat engine(s) will operate to bring the DHW tank temperature up
to 6OC before turning off again.
If the temperature of the internal fl ow pipework (heat engine) was to
drop to 3OC the heat engine(s) will operate until the temperature reg-
istered by the heat engine return sensor reaches 16OC. This will also
heat up the tank temperature to around 16OC
1.2.5 Nominal capacity
The capacity in litres of the in-built DHW tank is given in this table:-
Tank size 200 litres
Models SC 15/201
SC 25/201
SC 35/201
SC 45/201

Introduction 6 MAXXfl o EVO Lite
2 Introduction to the heater controls
2.1 The Graphical User Interface (GUI)
1 Control knob (press to enter)
2 Reset switch (under plastic cover)
3 Graphical User Interface
2.1.1 GUI Basics
The control knob is used to operate the GUI. The display is or-
ganised into a navigation bar, status bar, and work area.
The water heater is operated by rotating to move the selector
over the screen then pushing to select the item. When selected
the item will be displayed as inverse and can then be changed by
rotating and the change is confi rmed by pushing (enter).
If the item was selected by mistake, take your hand away
from (do not push to enter).Wait for 5 seconds and the
item will de-select and revert to its previous value.
In order to return to the previous screen select the back “arrow” or
“back” text in the bottom right corner of the screen at any time.
3
2
DHW temp 1 60.2
O
C
1
1
S
tatus bar
Home page
Hot water page
Navigation bar
Work area
Information page
Setup page
DHW temp 1 58.9 oC
1 1
1
1
1

Introduction 7 MAXXfl o EVO Lite
Not selected: The operating object is displayed normally, black on white background.
Preselected: The operating object is framed.
Selected: The operating object is inverted with white on black background.
2.2 Navigate and set using the control knob
Operating objects may have three display states:
To go to the navigation bar:
To set values in the work area:
Operating tips:
Turn control knob.
• The preselection is displayed with a frame around the symbol.
• The related topic page is displayed in the work area.
Press control knob.
• The symbol is selected on the navigation bar and is displayed inverted.
• The fi rst adjustable operating object of the work area is preselected.
Go back using the Back arrow on the navigation bar.
• The symbol in the navigation bar is once again preselected.
Turn control knob.
• The preselection is displayed with a frame around the operating object
Press control knob.
• The operating object is selected and is displayed inverted.
• The lower level is displayed if the operating object consists of multiple levels (e.g. Time
program).
Turn control knob. Set value.
Press control knob. Confi rm the set value.
• The set operating object is once again preselected.
Continue navigation
• To other pages, for selected and inverted displayed page titles.
Back “Back” goes a level higher within the work area.
Back arrow to return to navigation bar.
Editing time-out 5 seconds A changed setting reverts to the original state if not confi rmed
within this period.
Long button
pressure
> 3 seconds A long press of the knob on any expert view returns to the “Expert
view start page” (diagnostics page).
Locking time-out 1 minute Certain plant states are displayed in the foreground, e.g. Special
operations page. However, users are still able to go to any page
and set values. The foreground page returns after this period with-
out operator intervention.
Operating time-out 8 minutes The display switches automatically after this period without opera-
tion to the start page on the operator unit or display in standby on
the room unit.

Introduction 8 MAXXfl o EVO Lite
2.3 Display symbol meanings
The following symbols are located on the navigation bar (left, vertical):
The following symbols can be displayed on the status bar (top, horizontal):
Accessible for end-user and experts:
Start page: Heater status. Access to system operation mode.
DHW page. Access to temperature and time clock settings
Info pages:
• Messages (errors, events)
• Heater information
Service/setting pages:
• Setting options for domestic hot water system
• Operate special operations (e.g. for maintenance work)
• Login in expert view (see note below)
Available in addition for experts:
Diagnostic pages: Analyse and test heater and system.
Adjust/repair pages:
• Adapt parameters in ‘Complete parameter list’
Symbol ‘Alarm’ indicates a system error.
Symbol ‘Maintenance/Special operations’ indicates the presence of a maintenance message
or special operation feedback.
Symbol ‘Event’ indicates an event message from the system.
‘Hand’ symbol The ‘Hand’ symbol is displayed if the heater operation mode is being held “off ”
because hot water operation mode is set to off in the Domestic hot water page.
12:00 The device clock is synchronized with the clock from the connected controller.
Symbol ‘User’ and the number to the right (access level 1 to 3) indicate which user level is
currently active.
• None: User
• 1: Commissioning engineer
• 2: Heating engineer
• 3: OEM
Symbol ‘Producer’ indicates the water heater burner is currently operating and a fl ame has
been successfully detected.

User operation 9 MAXXfl o EVO Lite
Regional settings (1/3)
Time 13:28
Date 09.08.2016
1
1
1
1
1
3.0 User Operation
3.1 The home page
3.2 Setting the time and date
The home page for the heater GUI unit displays the most im-
portant information on the water heater and system operation
mode. There are no settings that can be applied whilst in this
screen.
To set the current time and date proceed with the following steps:
To set the time:
1. Rotate until the settings page symbol is highlighted then
press enter “Regional settings (1/3)” should already be prese-
lected.
2. Rotate to select the time fi eld then press enter
3. Rotate and enter a new hour value.
4. Rotate and enter a new minute value.
To set the date:
5. Rotate to select the date fi eld then press enter
6. Rotate and enter a new date, month and year after each
item is set.
7. Rotate for additional regional settings or exit regional set-
tings with “Back”.
8. It is also possible to adjust the dates set for the start and end
of summer time, for the purposes of automatic clock adjust-
ment.
DHW temp 1 58.9 oC
1
1
1
1
Back

User operation 10 MAXXfl o EVO Lite
1
3.3 Setting DHW Operating mode
3.4 Setting DHW temperature
Using select the Domestic hot water page and press enter
to view.
Rotate to select the operating mode, then press enter to
select and change the mode to “On”.
Using to highlight the “Nominal set point” press enter and
enter a new value and then enter within 3 seconds to confi rm.
1
1
Domestic Hot Water
Operating mode On
Temporary ...
Nominal set point 60oC
Time program 00 12 24
Domestic hot water
Operating mode Off
Temporary ---
Nominal set point ---
Time program 00 12 24
Domestic Hot Water
Operating mode On
Temporary ...
Nominal set point 62oC
Time program 00 12 24

User operation 11 MAXXfl o EVO Lite
1
1
3.5 Setting DHW heating time program
Select the Domestic Hot Water (DHW) page by rotating and
pressing . Toggle to the operating mode and ensure that
Domestic Hot Water is turned “On”.
With the DHW page selected, rotate to highlight the time
program fi eld, then press enter to open the time clock setting
page.
Select the day fi eld to change the times of that day. Press
to enter screen to set times for that day.
Domestic Hot Water
Operating mode On
Temporary ...
Nominal set point 60oC
Time program 00 12 24
Domestic Hot Water
Operating mode On
Temporary ...
Nominal set point 60oC
Time program 00 12 24
Domestic hot water
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
00 12 24
Back
1

User operation 12 MAXXfl o EVO Lite
Monday
Set time program
12:00 to 18:00
00 06 12 18 24
Back
Copy
Monday
Set time program
12:00 to 18:00
00 06 12 18 24
Back
Copy
1
Use to select and set existing time band.
Scroll to the beginning (00 hours) to insert another time band
(up to a total of 3 time bands per day can be set).
To delete a time band use to move the start and end times
of the band to be the same then press enter.
The time settings of any day can be copied and applied to
other days in the weekly schedule.
After setting up the times of the day required to be copied,
select copy in order to move to the “copy to screen”.
Using the select the day to be copied to and press enter.
Repeat this operation as required.
1
Copy Monday to
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Done
1

User operation 13 MAXXfl o EVO Lite
3.6 Temporary DHW operation function
Copy Monday to
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Done
Once times have been copied select “Done “ to return to Do-
mestic hot water page.
Outside of the programmed operation times for water heating, the
operation of the water heater can be turned on for a single occasion
where Hot Water will be heated to the nominal set point. The heater
control returns to normal operation using pre-settings as soon as the
hot water reaches set point.
Using enter the Domestic Hot Water page. Move the indicator
over the “Temporary” fi eld and press enter to highlight the fi eld.
Change the “Temporary” fi eld from “---” to “Recharging” and press
enter to activate Temporary operation mode.
Heater operation is now active and will recharge the DHW tank
water to the nominal set point previously programmed.
Once this function has been started it can only be stopped by
changing the operating mode to “on” then back to “off ”.
It is not possible to view or change the nominal set point
once this operation has been started. If you have any
doubts as to the current hot water set point, cancel the op-
eration (as described above) and start the heater using the
operation mode to view and set the nominal set point.
Domestic hot water
Operating mode Off
Temporary Recharging
Nominal set point ---
Time program 00 12 24
1
Domestic Hot water
Operating mode Off
Temporary ---
Nominal set point ---
Time program 00 12 24

User operation 14 MAXXfl o EVO Lite
3.7 Information pages
Information regarding the operation state of the water heater
can be viewed by selecting “ ” pages and pressing enter.
In this example the screen is showing the status of DHW and
the tank temperature:-
To view additional info pages rotate
In this example the screen is showing the status of DHW and
the temperature of the heated water entering the top of the hot
water tank from the heat engine.
Domestic hot water
Charging active
DHW temp 1 58.6oC
Boiler
In operation for domestic hot water
Boiler temp 62.0oC
1

User operation 15 MAXXfl o EVO Lite
3.8 Error messages
If the heater controls are unable to operate the gas burner or it
detects a undesirable condition, the controls will put the heater
into a “lockout” mode and the heater may be prevented from
operating again, until manually reset.
If the error detected is a minor one, the controls will allow the
heater to operate normally, but in either case an error mes-
sage symbol will be displayed in the status bar and a
text explanation will be displayed on the home screen and in
the Information menu. Any important messages aff ecting the
operation of the heater should be displayed instead of the
normal “Home” screen.
Depending on the type of error, this may need to be cleared
before the heater will function again. Viewing the info page
(see 3.7) will provide greater detail of the error (refer to the
table in 3.8.1 for error codes).
In this example the heater has gone into a lockout mode,
because the gas supply has been interrupted. The resolution
would be to re-establish the gas supply to the heater and then
reset the error to restart heater operation again (see below).
To RESET an error message use to select Reset and
press enter. Within 3 seconds press enter again to con-
fi rm the Reset action. Provided the error condition has
been corrected the heater will run through the ignition
sequence again.
A Lockout condition should not be repeatedly reset. If
the condition persists then a qualifi ed repair engineer
should be consulted.
When a reset action has been applied a message is displayed
across the screen for about one second (see example oppo-
site).
Further diagnostic codes and the history of the last 20
error messages can be found by logging in as “En-
gineer” and accessing the “Error” menu. For details
on how to do this please refer to
section 4.2 of this
section 4.2 of this
manual.
manual.
1
Error
133: Safety time exceeded
Confi rm
i Reset
Error
133: Safety time exceeded
Reset
Error
133: Safety time exceeded
Reset

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.

User operation 17 MAXXfl o EVO Lite
3.8.1 Error codes (continued)
Error
Code Error Code Description Diag. Code Notes
110 SLT Lockout 306 431
432 433
434 435
436 756
Electronic temperature limits exceeded. General overheating issue. Check for
pump operation, trapped air and heat exchanger blockages. Monitor tempera-
tures of system to establish problem area.
429 818 Safe reset of the error sub code 433 (see above) has not been met. Allow the
water heater to cool further before resetting.
305 412
550 551
754
Mechanical overheat protection circuit is open circuit (connection X18 on
control PCB). Check connector is fully inserted
426 437
815
Flow temperature heat up gradient exceeded. Check pump operation and
presence of trapped air in the heat exchanger. Flow through heat exchanger
may be restricted.
438
817
Maximum Delta T of system exceeded. Check pump operation and presence
of trapped air in the heat exchanger. Flow through heat exchanger may be
restricted.
428 Maximum Delta T of system exceeded. Initial starting of the pump before the
burner is operated, can cause this error. If accompanied by code 429 within
the same minute, this error can be disregarded.
429 Safe reset of the error sub code 428 /438 (see above). Allow the water heater
to cool further before resetting.
427 816 Safe reset criteria has not been met. Allow the water heater to cool further
before resetting.
420 421
819 820
Return temperature greater than fl ow temperature. Check that the fl ow and
return sensors are operating correctly
419 430
813 814
Flow temperature limit exceeded. Check for overheating issues and fl ow sen-
sor (B2) performance.
809 810
422 423
Flow temperature not plausible - Reading less than 0OC or greater than
124OC . Check fl ow sensor (B2) and replace if necessary.
425
812
Return temperature limit exceeded. Check for overheating issues and return
sensor (B7) performance.
424
811
Return temperature not plausible - Reading less than 0OC or greater than
124OC . Check return sensor (B7) and replace if necessary.
111 Shutdown limit
thermostat
264 Heat exchanger temperatures have been exceeded. Investigate fl ow rates
and controls to determine causes of temporary fault code.
125 Maximum boiler
temperature
exceeded
286 500
740
Temperature supervision lockout. Check pump, shutoff valves, burner and
fl ow rates before resetting
501 Temperature has not increased at fl ow sensor after burner start. Check fl ow
sensor is correctly clipped to pipe work.
502 Temperature has not increased at return sensor after burner start. Check
return sensor is correctly clipped to pipe work.
126 DHW charging
temperature not
reached
72 Charging temperature not achieved within parameterised time scale. Check
operation and heat up times for heater
127 DHW legionella
temperature not
reached
73 Check operation of legionella function and DHW system. Legionella setpoint
has not been achieved within 48 hours of the legionella function operating.
When using a secondary return system and sensor, do not set the legionella
function setpoint too high, as the heat losses of the hot water pipework may
not permit this setpoint to be achieved at the return point before the heater.

User operation 18 MAXXfl o EVO Lite
3.8.1 Error codes (continued)
Error
Code Error Code Description Diag. Code Notes
128 Loss of fl ame
during operation
244
625
Count of loss-of-fl ame incidents exceeded (a maximum of 15 loss of fl ame inci-
dents are permitted in a 24 hour period )
394
834
Flame lost in operation during safety time, before the start of the modulation
phase. Check the burner CO2 is set correctly. Check operation and condition of
the ionisation electrode.
854 Flame lost in operation within the fi rst 7 seconds after safety time. Check the
burner CO2 is set correctly. Check operation and condition of the ionisation elec-
trode.
253 Flame lost in modulation phase
130 Flue gas temper-
ature too high
Any Check causes of high temperatures before operating Appliance. Inspect inside of
heat exchanger for dirt build up. Check CO2 levels at min and max output.
133 Safety time ex-
ceeded
254
395
755
Records individual ignition failures and the times they have occurred. Check gas
supply, spark electrode, spark generator, Ionisation probe, burner CO2 setting
and fl ue system
245
625
757
A total of 5 unsuccessful ignition attempts has occurred within a 24 hour period,
resulting in a permanent lockout
142 Device failure
(Bus)
Any Check that the appliance and any OZW672 is powered and connected correctly.
151 BMU Internal
error
330 Error when closing ignition relay - Check ignition generator and connections from
controls - Replace control PCB if no fault found
331 Error when opening ignition relay - Check ignition generator and connections
from controls - Replace control PCB if no fault found
332 Error when closing gas valve relay - Check gas valve and connections from con-
trols - Replace control PCB if no fault found
333 Error when opening gas valve relay - Check gas valve and connections from
controls - Replace control PCB if no fault found
336
337
Internal safety relay error - Check if polarity of live and neutral has been reversed
to the appliance. Replace PCB if fault repeatedly occurs.
152 Parameterization
error
Any Incorrect / confl icting parameters input (last changed parameters need to be
investigated).
All
others
Fan speed setting error. For example the ignition speed cannot be set lower than
the minimum fan speed - Review fan speeds and adjust.
153 Unit Locked 622 Temperature inside the appliance casing has exceeded 90OC. Check burner door
seals and door nuts are correctly tightened. Activating a reset for more than 10
seconds will also produce this lockout.
848
849
Parameter update fi nished. Press reset to apply changes.
160 Fan speed
threshold not
reached
233
749
Fan does not reach required speed setpoint via PWM control- Check wiring and
operation of fan. Replace fan if necessary
377 Fan speed not reached - Home run stage
378 Fan speed not reached - Standby stage
379 Fan speed not reached - Ignition stage
380 Fan speed not reached - Pre purge stage
381 Fan speed not reached - Post purge stage
171 Fault input 1 Any User defi ned OZW672 input D1 has been activated.
172 Fault input 2 Any User defi ned OZW672 input D2 has been activated.
183 Unit in param-
eterisation mode
770 Code will be displayed when a programming stick is used but should clear when
programming is complete. Repeat stick operation if fault code persists
Any Press reset after any programming has been actioned to remove lockout

User operation 19 MAXXfl o EVO Lite
3.8.1 Error codes (continued)
Error
Code Error Code Description Diag. Code Notes
217 Sensor error 765
766
Short circuit of Ionisation circuit. Check operation of ionisation probe using pa-
rameter 8329 (menu - Diagnostics heat generation). Ionisation probe may need
replacing. Check electrical supply to the heater and burner - pay special attention
to the earth circuit and supply.
317 Grid frequency
outside permitted
range
275
461
The frequency (Hz) of the electrical supply is outside permitted tolerance. Check
electrical supply to heater.
324 Input BX, same
sensors
110 BX sensor duplicated - Two sensor inputs have been defi ned twice with the same
sensor type (e.g. B3). Review last parameters programmed to remove duplica-
tion.
325 Input BX/exten-
sion mod, same
sensors
Any BX expansion module 1 sensor duplicated - Two sensor inputs have been de-
fi ned twice with the same sensor type (e.g. B3). Review last parameters pro-
grammed for the expansion module to remove duplication.
327 Extension mod,
same function
Any AGU2.5 expansion module function duplicated - check parameter setup (in “Con-
fi guration” menu)
335 /
336
Sensor input
BX21 / BX22
without function
211 /
212
A sensor has been detected connected to BX21 of the AGU2.5 expansion mod-
ule 1, but not defi ned. Defi ne the sensor using the parameters or remove the
sensor if not required.
All
other
As above except the undefi ned sensor is connected to an AGU2.5 expansion
module 1. The AGU2.5 expansion module should be defi ned as module 1 -
Check the dip switches on the front of the device is set correctly
384 Extraneous light 252
393
Ionisation current detected before whilst in standby mode. Check ionisation
current (“Diagnostics producer” parameter 8329). If there is a current present is
greater than 0.61 whilst the burner is in standby, turn off gas supply to check gas
valve is closing completely. If current is still present, remove ionisation probe and
use a screwdriver to clear the opening through the burner door before replacing
the probe and testing again.
Persistent errors may indicate that the burner is only operational for very short
periods. Try increasing the switching differential by at least 1OC (parameter 5024)
to increase burner run time.
Other Ionisation current detected during ignition phase before the gas valve is opened.
385 Mains under volt-
age
554
555
Mains voltage below 185v - check electrical supply to the appliance.
386 Fan speed toler-
ance
388 Fan outside allowed speed tolerance during standby phase
531
389
Fan outside allowed speed tolerance during pre-purge phase
374
383
384
Fan outside allowed speed tolerance during ignition phase.
375
386
Fan outside allowed speed tolerance during min modulation phase.
385 Fan outside allowed speed tolerance during max modulation phase.
532
534
382
390
Fan outside allowed speed tolerance during post-purge phase
Other Check connections and wiring loom of the fan. Replace fan if no fault found. If
necessary use parameter 9650 Chimney drying mode to test the function of the
fan without having to operate the burner.
432 Function earth
not connected
Any No Ignition earth, X1 / X17 not connected or earth fault. Check internal and exter-
nal earth wiring to the heater
433 Heat exchange
temperature
Any Heat exchanger temperature is too high. Investigate all sources of overheating.
When the issue has been resolved examine the heat exchanger for damage
before putting back into operation.
NA DHW Operating
mode locked
Any Check to see if the remote enable link wire is fi tted or external controls wired to
these terminals are closing this circuit. To activate DHW operation this circuit
must be closed.

User operation 20 MAXXfl o EVO Lite
Maintenance
105: Maintenance message
3.9 Maintenance messages
Example
The display will show a symbol if the heater is reporting a
maintenance issue. The heater will continue to operate as normal,
but it may in future stop if the maintenance message is ignored and
an error develops as a result.
In this example ‘105: Maintenance message’ is used to notify
the user, the heater has been in operation for more than 12
months and requires a service inspection. When servicing has
been completed, the service counter should be reset using
parameter 7045, in the Service / special operation menu
(see
installation and maintenance manual section 9.2.1).