Atag i24C Quick start guide

Appliance
Technical Guide
SERVICE ENGINEER EDITION
2019 ONWARDS

2
The heating
industry has
just had an
upgrade
We will help you grow and protect
your business.
Now you
have too

3
Contents
APPLIANCES COVERED AND SERIAL NUMBER 4
iC & iC ECONOMISER PLUS COMBINATION
BOILERS TECHNICAL DATA 5
iS SYSTEM & iR REGULAR BOILERS
TECHNICAL DATA 6
BOILER LAYOUT 7
CONTROL PANEL 8
CONTROLS AND EXPLANATION
OF THE FUNCTIONS 9
Central heating system 9
Change the central heating setpoint temperature 9
Hot water supply 1 0
Change the domestic hot water
setpoint temperature 1 0
Comfort and eco 1 1
Always Active 1 2
Time Based 1 3
Disabled 1 4
Frost protection - the danger of frost 1 5
Air Purge Program 1 6
Commissioning the boiler 1 7
Water pressure sensor 1 8
Flow switch 1 8
COMBI BOILER CENTRAL HEATING MODE CH 1 9
COMBI BOILER HOT WATER MODE DHW 20
Combi boiler CH mode 2 1
Combi boiler DHW mode 2 1
System & regular boiler central
heating mode 2 1
CHECKING COMBUSTION CO222
TECHNICAL MENU 25
PARAMETER CHAPTER 26
PARAMETER LISTING 27
YOU HAVE UPGRADED TO ATAG, WE WILL HELP YOU TO GROW AND PROTECT YOUR BUSINESS
TESTING THE BOILER AND CHANGING
SETTINGS 30
Boiler Manual test setting 30
Gradient speed CH 3 1
SETTING UP INTEGRAL AND EXTERNAL
CONTROLS OPTIONS 32
Integral programmer 33
BOILER INFORMATION 34
Set the heating time periods
(if using integral programmer) 35
To set in time periods 36
Free time programming 37
Home screen settings 38
Setting up installer details
to display on boiler 39
Annual Service reminder 40
WEATHER COMPENSATION 4 1
SETTING THE WEATHER COMPENSATION 42
EQUIVALENT FLUE LENGTHS 44
RESET A FAULT CODE 44
VIEW ERROR CODE HISTORY 45
Error codes 45
RESISTANCE TABLE SENSORS 47
ELECTRICAL DIAGRAM 48
ELECTRICAL FUNCTIONS 49
ATAG 3PORT EXTERNAL DIVERTER VALVE KIT
(vented cylinder) 52
(unvented cylinder) 54
ROUTINE SERVICING 56
Full Service 58
IGNITION ELECTRODE 6 1
EXPANSION VESSEL 62

MODEL GC NUMBER
i24C Combination Boiler 47-310-36
i28C Combination Boiler 47-310-37
i36C Combination Boiler 47-310-38
i40C Combination Boiler 47-310-39
iC Economiser 27 Plus Combination Boiler 47-310-40
iC Economiser 35 Plus Combination Boiler 47-310-41
iC Economiser 39 Plus Combination Boiler 47-310-42
i15S System Boiler 41-310-44
i18S System Boiler 41-310-45
i24S System Boiler 41-310-46
i32S System Boiler 41-310-47
i40S System Boiler 41-310-48
i15R Regular Boiler 41-310-49
i18R Regular Boiler 41-310-50
i24R Regular Boiler 41-310-51
i32R Regular Boiler 41-310-52
i40R Regular Boiler 41-310-53
SERIAL NUMBER: P184510289
P 18 45 1 0289
YEAR WEEK DAY No.
Appliances covered
and serial number
LPG conversion kits for each boiler available
4

iC & iC Economiser Plus combination
boilers technical data
iC ECONOMISER PLUS COMBINATION BOILERS iC Economiser 27 Plus iC Economiser 35 Plus iC Economiser 39 Plus
Part number BE200327 BE200335 BE200339
ErP Seasonal space heating energy eciency class A A A
ErP Seasonal space heating energy eciency (%) 94 94 94
ErP Water heating energy eciency class A A A
ErP Water heating energy eciency (%) 94 96 96
ErP Declared load profile DHW XXL XXL XXL
DHW input (kW) 29.8 40.3 42.5
CH output (kW) 23.2 31.2 31.2
Hot water flow rate @ 35°C rise (l/min) 12.6 16.1 17.0
SEDBUK 2009 (%) 89.7 89.7 89.7
Dimensions (H x W x D) (mm) 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355
Boiler lift weight with jig (Kg) 43 46 46
Standard warranty (years) 10 10 10
LPG conversion kit available Yes Yes Yes
NOx class / NOx mg / kWh 6 / 30.02 6 / 25.71 6 / 25.71
Ingress protection (IP) IPX4D IPX4D IPX4D
Maximum equivalent horizontal flue length (m) 60/100mm 15 8 8
Maximum equivalent vertical flue length (m) 60/100mm 15 8 8
Maximum equivalent horizontal flue length (m) 80/125mm 50 40 40
Maximum equivalent vertical flue length (m) 80/125mm 50 40 40
IC COMBINATION BOILERS i24C i28C i36C i40C
Part number BC100324 BC100328 BC100336 BC100340
ErP Seasonal space heating energy eciency class A A A A
ErP Seasonal space heating energy eciency (%) 94 94 94 94
ErP Water heating energy eciency class A A A A
ErP Water heating energy eciency (%) 85 84 90 90
ErP Declared load profile DHW XL XL XL XL
DHW input (kW) 26.6 30.3 39.3 42.0
CH output (kW) 23.2 23.2 31.2 31.2
Hot water flow rate @ 35°C rise (l/min) 10.1 11.5 14.9 16.2
SEDBUK 2009 (%) 89.7 89.7 89.7 89.7
Dimensions (H x W x D) (mm) 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355
Boiler lift weight with jig (Kg) 41 41 44 44
Standard warranty (years) 10 10 10 10
LPG conversion kit available Yes Yes Yes Yes
NOx class / NOx mg / kWh 6 / 30.02 6 / 30.02 6 / 25.71 6 / 27.10
Ingress protection (IP) IPX4D IPX4D IPX4D IPX4D
Maximum equivalent horizontal flue length (m) 60/100mm 15 15 9 9
Maximum equivalent vertical flue length (m) 60/100mm 15 15 9 9
Maximum equivalent horizontal flue length (m) 80/125mm 50 50 45 45
Maximum equivalent vertical flue length (m) 80/125mm 50 50 45 45
5

iS SYSTEM BOILERS i15S i18S i24S i32S i40S
Part number BS300315 BS300318 BS300324 BS300332 BS300340
ErP Seasonal space heating energy eciency class A A A A A
ErP Seasonal space heating energy eciency (%) 93 93 94 94 94
CH output kW (50/30°C) 14.7 17.5 23.2 31.2 38.8
SEDBUK 2009 (%) 89.8 89.8 89.8 89.8 89.8
Dimensions (H x W x D) (mm) 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355
Boiler lift weight with jig (Kg) 39 39 39 42 42
Standard warranty (years) 10 10 10 10 10
LPG conversion kit available Yes Yes Yes Yes Yes
Solar compatible Yes Yes Yes Yes Yes
NOx class / NOx mg / kWh 6 / 28.90 6 / 28.74 6 / 30.02 6 / 25.71 6 / 27.10
Ingress protection (IP) IPX4D IPX4D IPX4D IPX4D IPX4D
Maximum equivalent horizontal flue length (m) 60/100mm 15 15 15 9 9
Maximum equivalent vertical flue length (m) 60/100mm 15 15 15 9 9
Maximum equivalent horizontal flue length (m) 80/125mm 50 50 50 45 45
Maximum equivalent vertical flue length (m) 80/125mm 50 50 50 45 45
iR REGULAR BOILERS i15R i18R i24R i32R i40R
Part number BR400315 BR400318 BR400324 BR400332 BR400340
ErP Seasonal space heating energy eciency class A A A A A
ErP Seasonal space heating energy eciency (%) 94 94 94 94 94
CH output kW (50/30°C) 14.7 17.5 23.2 31.2 38.8
SEDBUK 2009 (%) 89.8 89.8 89.8 89.8 89.8
Dimensions (H x W x D) (mm) 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355 700 x 440 x 355
Boiler lift weight with jig (Kg) 32 32 32 35 35
Standard warranty (years) 10 10 10 10 10
LPG conversion kit available Yes Yes Yes Yes Yes
Solar compatible Yes Yes Yes Yes Yes
NOx class / NOx mg / kWh 6 / 28.90 6 / 28.74 6 / 30.02 6 / 25.71 6 / 27.10
Ingress protection (IP) IPX4D IPX4D IPX4D IPX4D IPX4D
Maximum equivalent horizontal flue length (m) 60/100mm 15 15 15 9 9
Maximum equivalent vertical flue length (m) 60/100mm 15 15 15 9 9
Maximum equivalent horizontal flue length (m) 80/125mm 50 50 50 45 45
Maximum equivalent vertical flue length (m) 80/125mm 50 50 50 45 45
iS system and iR regular
boilers technical data
6

iC ECONOMISER PLUS COMBINATION BOILER LAYOUT
1Heat exchanger 9Control panel 17 Safety valve
2Ignition unit 10 Three-way valve 18 DHW Economiser
3Fan unit 11 Circulation pump 19 Siphon
4Air supply damper 12 Filling loop 20 Isolation valve flow CH
5Gas valve 13 Flue gas exhaust 21 Isolation valve gas
6Automatic de-aerator 14 Combustion air supply 22 Isolation valve cold water
7DHW plate heat exchanger 15 Boiler data plate 23 Isolation valve return CH
8Control unit 16 Expansion vessel 24 Flue non return valve
T1 Flow sensor P1 Water pressure CCondensation pipe
T2 Return sensor GGas pipe KCold water pipe
T3 Hot water sensor AFlow pipe CH WHot water pipe
F1 DHW flow sensor RReturn pipe CH
Boiler layout
20
A W G
21
K
22
R
23
13
14 5
24 6
3
2 1
16
T1
P1
T2
18 15
7 4
11 9
12
817
19C
F1
T3
10
7

Control panel
(All ATAG boiler range)
RESET
BACK OK
19°25/07/18 09:00
23.2º
75°45°
ECO AUTO
Press OK to enter Menu
1.4 bar
00 02 04 06 08 10 12 14 16 18 20 22 24
1
BC A
D E
Controller buttons
ASelector Wheel Turn the wheel left or right to scroll through available menu options
BOK button Press to select/confirm an item
CBACK button Press to go back one screen
DRESET button Press to reset a fault code
EChimney sweep button Press to enter into service mode which button allows adjustment of high fire/low fire and CO2 settings
Controller display
1DHW comfort or economy mode is active 11 Boiler status indicator, such as "Press OK to enter Menu", error messages and
other status information
2DHW status symbol. A box around the tap symbol indicates DHW is in operation
3Visual illustration of current hot water temperature. Scale changes as the set
temperature is changed
12 Heating supply setpoint
13 Outdoor temperature (if connected)
4Internal room temperature (if present) 14 Time program
5DHW set point temperature 15 Visual illustration of current central heating temperature. Scale changes as the
set temperature is changed
6CH time program active
7Flame Burner on 16 Central heating status symbol. A box around the radiator symbol indicates
central heating is in operation
8Current date and time
9Actual Power Level 17 Thermoregulation function enabled
10 Current central heating system water pressure
5 76 8 9 10 11 12 13
14
15
16
171
2
3
4
8

Central heating system
The CH program is always active after start-up.
This is indicated by a rad symbol .
If there is heat request, it is indicated by a square around the rad symbol
and the description at the bottom of the screen of ‘C.Heating Active’.
The heating will be put into operation. The circulation pump will switch on
and the burner will switch on after 1 to 2 minutes (flame icon) .
When there is no more heat requested the radiator symbol may have the
square around it or not, but the flame (flame icon) symbol will disappear.
The pump will continue to run for 60 seconds due to the pump over run
feature. The description at the bottom of the screen of ‘CH Pump Overrun’.
From the controller Home screen,
press OK.
1
Controls and explanation
of the functions
19°25/07/18 09:00
80°60°
ECO AUTO
C.Heating Active
1.5 bar
00 02 04 06 08 10 12 14 16 18 20 22 24
RESET
BACK OK
19°25/07/18 09:00
80°60°
ECO AUTO
Press OK to enter Menu
1.5 bar
Turn the selector wheel to highlight
Complete Menu. Press OK.
2
CH Settings is highlighted.
Press OK.
3
Option CH Setpoint Temp is
highlighted. Press OK.
4
Option T set Z1 is highlighted.
Press OK.
Note: T set Z2 and T set Z3 are inactive functions.
5
Turn the selector wheel until the
desired temperature appears on
the screen. Press OK.
Available temperature settings:
20°C - 80°C
6
Change the central heating setpoint temperature
Time program / Manual
Summer / Winter / OFF
Complete Menu
T set Z1
T set Z2
T set Z3
80
80
80
CH Settings
DHW Settings
Screen Settings
CH Setpoint Temp
Time program
Holiday function
AUTO function
Pump continuous running
T set Z1
Set the send temperature of zone 1
80°C
Press OK to confirm
9

Hot water supply
The DHW program is always active after start-up.
This is indicated by a tap symbol .
If there is a hot water request, this is indicated by a square around
the tap symbol and the description at the bottom of the screen
of ‘ DHW Active’. The hot water supply will be activated.
The circulation pump will start circulating and the burner will switch
on (flame icon) .
The pump will continue to run for 30 seconds due to the pump
over run feature. The description at the bottom of the screen
of ‘DHW pump over run’ (combi boiler or system boilers
with ATAG 3-port diverter kit).
19°25/07/18 09:00
80°60°
ECO AUTO
DHW Active
1.5 bar
From the controller Home screen,
press OK.
1
RESET
BACK OK
19°25/07/18 09:00
80°60°
ECO AUTO
Press OK to enter Menu
1.5 bar
Turn the selector wheel to highlight
Complete Menu. Press OK.
2
Turn the selector wheel to highlight
DHW Settings. Press OK.
3
Option DHW Comfort Setpoint
Temp is highlighted. Press OK.
4
The current DHW comfort Setpoint
temperature is displayed. Press OK.
5
Turn the selector wheel until the
desired temperature appears on
the screen. Press OK.
Available temperature settings:
40°C - 65°C
6
Change the domestic hot water setpoint temperature
Time program / Manual
Summer / Winter / OFF
Complete Menu
DHW comfort Setpoint Temp 60
CH Settings
DHW Settings
Screen Settings
DHW comfort Setpoint Temp
Time program
Comfort function
DHW comfort Setpoint Temp
Set the domestic hot water temperature
60°C
Press OK to confirm
10

Comfort and eco
ECO and COMFORT are the hot water preheat settings, COMFORT for ON or ECO for OFF.
By default the hot water supply is set to ECO.
COMFORT mode is a domestic hot water setting that enables the boiler to fire up more often
to maintain the heat exchanger temperature. If COMFORT is selected the keep hot facility will
heat the water to the selected DHW temperature on the front of the boiler. This enables quicker
delivery of hot water to hot water fixtures.
ECO mode will result in a possible longer DHW waiting time, because the boiler will not being
fired up for pre-heating the hot water supply.
By default the hot water supply is set to ECO and COMFORT mode is disabled (turned o).
To enable (turn on) COMFORT mode, follow the steps below.
COMFORT MODE HAS THREE OPTIONS:
Option 1: Always Active
This option provides continuous hot water all day long. The boiler maintains the primary heat
exchanger temperature to quickly deliver hot water to the plate heat exchanger. This selection
provides the quickest delivery of hot water to hot water taps, but uses the most energy
(COMFORT mode will be displayed on the home screen).
Option 2: Time Based
The boiler maintains the primary heat exchanger temperature based on the time selections.
This selection requires more energy use than when disabled, but not as much energy use as
the “Always Active” option (COMFORT or ECO with a time clock logo will be displayed on the
home screen depending which mode it is in).
Option 3: Disabled
The boiler operates and produces hot water; however, it will not maintain the primary heat
exchanger temperature for quicker hot water production. This selection saves some energy, but
requires longer time to provide hot water to the hot water taps (ECO mode will be displayed on
the home screen).
19°25/07/18 09:00
80°60°
ECO AUTO
DHW Active
1.5 bar
19°25/07/18 09:00
80°60°
ECO AUTO
DHW Active
1.5 bar
11

From the controller Home screen,
press OK.
1
RESET
BACK OK
19°25/07/18 09:00
80°60°
ECO AUTO
Press OK to enter Menu
1.5 bar
Turn the selector wheel to highlight
Complete Menu. Press OK.
2
Turn the selector wheel to highlight
DHW Settings. Press OK.
3
Turn the selector wheel to highlight
Comfort function. Press OK.
4
Turn the selector wheel to highlight
Always Active. Press OK.
5
The message in the screen appears.
The Always Active mode is now
selected.
6
Always Active
In always active mode COMFORT will be displayed continuously on the front display. To enable the Always Active comfort mode setting,
Follow the steps below.
Time program / Manual
Summer / Winter / OFF
Complete Menu
Disabled
Time based
Always Active
CH Settings
DHW Settings
Screen Settings
DHW comfort Setpoint Temp
Time program
Comfort function
Comfort function set to: Always active
The boiler will be ignited to quickly provide Hot
Water all day long
12

From the controller Home screen,
press OK.
1
RESET
BACK OK
19°25/07/18 09:00
80°60°
ECO AUTO
Press OK to enter Menu
1.5 bar
Turn the selector wheel to highlight
Complete Menu. Press OK.
2
Turn the selector wheel to highlight
DHW Settings. Press OK.
3
Turn the selector wheel to highlight
Comfort function. Press OK.
4
Turn the selector wheel to highlight
Always Active. Press OK.
5
The message in the screen appears.
The Time Based mode is now selected.
6
Press the BACK button one time.
Turn the selector wheel to highlight
Time program. Press OK.
Select one of the two options:
Free Time Programming - User
defined times for when confort is acive
Preset programs - options for preset
times for comfort mode to be active.
DHW is highlighted.
Press OK.
Time Based
In time based mode a clock icon is displayed next to the ECO or COMFORT on the front screen to indicated this time based mode.
To enable the Time Based comfort mode setting, follow the steps below.
Time program / Manual
Summer / Winter / OFF
Complete Menu
Disabled
Time based
Always Active
CH Settings
DHW Settings
Screen Settings
DHW comfort Setpoint Temp
Time program
Comfort function
DHW comfort Setpoint Temp
Time program
Comfort function
Free Time Programming
Preset programs
DHW
Comfort function set to: Time Based
Turn the selector wheel to highlight
Set time program. Press OK.
You then select the days with the
same time program. Use the selector
wheel to scroll to the day(s) you want
the same. Select OK on each day that
will have the same schedule.
Set Comfort T
Set Reduced T
Set time program
7
8
9
10
11
13

Disabled
In disabled mode ECO will be displayed continuously on the front display.
To enable Disabled (factory setting) comfort mode setting, follow the steps below.
From the controller Home screen,
press OK.
1
RESET
BACK OK
19°25/07/18 09:00
80°60°
ECO AUTO
Press OK to enter Menu
1.5 bar
Turn the selector wheel to highlight
Complete Menu. Press OK.
2
Turn the selector wheel to highlight
DHW Settings. Press OK.
3
Turn the selector wheel to highlight
Comfort function. Press OK.
4
Option Disabled is highlighted.
Press OK.
5
The message in the screen appears.
Comfort mode is now disabled.
6
Time program / Manual
Summer / Winter / OFF
Complete Menu
Disabled
Time based
Always Active
CH Settings
DHW Settings
Screen Settings
DHW comfort Setpoint Temp
Time program
Comfort function
Comfort function disabled
14

From the controller Home screen,
press OK.
1
RESET
BACK
19°25/07/18 09:00
80°60°
COMFORT AUTO
Press OK to enter Menu
1.5 bar
OK
Turn the selector wheel to highlight
Complete Menu. Press OK.
2
Frost protection - the danger of frost
If there is danger of frost damage to the CH installation and there is no outside sensor connected, it is advisable to let the pump run
continuously. If the pump is set to continuously this is displayed by a solid frost symbol (frost icon) .
To set pump to continuously on, proceed as follows:
Time program / Manual
Summer / Winter / OFF
Complete Menu
CH Settings is highlighted.
Press OK.
3
CH Settings
DHW Settings
Screen Settings
Turn the selector wheel to highlight
Enable. Press OK.
If the pump is set to continuously
running the frost icon is displayed.
5
Pump continuous running
Disabled Enabled
Turn the selector wheel to highlight
Pump continuous running. Press OK.
4
CH Setpoint Temp
Time program
Holiday function
AUTO function
Pump continuous running
Boiler frost protection
The boiler frost protection is based on the water temperature
measured by the flow T1 sensor in the heat exchanger. When the
measured T1 temperature gets below 8°C in the boiler, the boiler pump
starts for 2 minutes and the 3-way valve will switch 1 minute to CH and
1 minute to DHW. if the T1 temperature has descended < 4°C the pump
will run and the burner will be started on low load for 30 seconds,
when T1 temperature is > 8°C, burner will be switched OFF.
DHW frost protection: if the cylinder temperature is below 8°C the
burner will be started and stops when temperature reaches 12°C
In this mode the frost symbol (frost icon) will flash.
Installation frost protection
For this type of protection an outside sensor must be connected, if no
outside sensor is connected the installation frost protection is not active.
When the outside sensor measures a temperature between 1.5°C
and -4°C the boiler pump will come on for 10 minutes every 6 hours.
When the outside temperature gets to -5°C or lower the pump will run
continuously.
When the outside temperature gets above 1.5°C again, the installation
frost protection is o. In this mode the frost symbol (frost icon) will be
continuously on solid.
THERE ARE TWO TYPES OF FROST PROTECTION INTEGRATED IN THE BOILER, FROST PROTECTION OF THE BOILER AND FROST
PROTECTION OF THE INSTALLATION.
15

Pump kick and diverter valve kick
Every 24 hours, if there is no heat demand from heating or DHW
the pump will be started for 10 seconds and the diverter valve will
be opened and closed again. This is done to prevent the pump and
diverter valve from sticking.
Boiler anti-cycle time
If during a demand for central heating the burner switches o, because
the desired flow temperature is exceeded, there will be an anti-cycle
time in operation for 5 minutes. This means that the burner switches on
again after 5 minutes if there is still a demand for the heating.
Pump overrun
After the heating demand the burner will shut down and the pump will
run for a further 60 seconds. This can be changed in parameter 2.3.7
from 1 - 16 minutes. After DHW demand it would be 30 seconds if T1 is
<75°C or 3 minutes if T1 >75°C.
Air Purge Program (Combi and System boilers)
The boiler is equipped with an automatic air purge program.
The installation system needs to be filled with water and bled free of
air before turning power onto the boiler. Then the automatic air purge
program will ensure that the boiler is free of air before firing up.
The automatic air purge program starts when the water pressure in the
boiler gets to 1.1 bar. The display will show ‘Air purge Active’ on the
screen with the current central heating system water pressure.
The complete program for the boiler air purge takes 7 minutes.
During these 7 minutes, the pump is started and stopped, and the
three-way diverter valve is alternately sent to the heating and to the
DHW position several times and with short pauses to make sure that
the air inside the boiler leaves through the automatic air vent.
System boiler
Same as combi, but there is no internal diverter valve to move.
Regular boiler
Same as combi, but there is no diverter valve to move or a pressure
reading and there is a feed & expansion tank.
16

Make sure before the boiler is put into operation that the boiler and installation have been fully vented. Vent the gas line and open the gas isolation
valve to the boiler. The boiler requires no adjustment of the burner pressure and quantity as it has been set in the factory and should not be reset.
Commissioning the boiler
Turn on the boiler
electrical supply.
After filling the 7 minute air purge program
starts;
Device discovery...
14.09.18
Airpurge active
1.7 bar
19°25/07/18 09:00
80°60°
ECO AUTO
DHW Active
1.1 bar
19°25/07/18 09:00
80°60°
ECO AUTO
DHW Active
1.1 bar
1
Vent the entire heating installation
starting at the lowest point;
4
When the boiler starts up for the first time
the following screens will be shown:
Initializing...
14.09.18
2
Check the water pressure and top up if
necessary to 1.0 – 1.2 bar;
5
3
17

Water pressure sensor
This sensor control has following settings:
0.5 bar: below this pressure the burner is blocked for operation
0.5 to 0.8 bar: boiler will reduce Tset max by 5°C
0.8 to 3.0 bar: boiler fully functional
3.0 bar: above this pressure the boiler is blocked for operation
The pressure sensor is also used to set the boiler free before every start.
Before the burner is set free the boiler does a pump check, it checks for
an increase in pressure when the pump starts. If there is an increase of
water pressure, the boiler will fire up. If there is no increase the burner is
blocked.
Flow switch (Regular boiler)
In the regular boiler there is no pump inside and because of the low pressure there is no pressure sensor inside as well.
To register if the system pump is working and there is water in the system there is a flow switch and this flow switch sets the burner free.
The iC, iC Economiser Plus & iS boilers are supplied with a pressure sensor.
If the water pressure drops below 0.8 bar the text "Warning 1P4 Filling Needed" will appear
in the screen;
Between 0.5 and 0.8 bar and the boiler will reduce Tset max by 5°C.
If the water pressure drops below 0.5 bar the text "Fault 108 Filling Needed, Restore the pressure
in the heating circuit " will appear in the screen; The air purge program starts when the water
pressure has been below 0.5 bar. The automatic air purge program will take approx. 7 minutes
and will be followed by the home screen when the water pressure is taken above 1.2 bar.
Filling Needed
ALERT
Warning 1P4
25/07/18 09:00 0.7 bar
Filling Needed
ALERT
Fault 108
25/07/18 09:00 0.4 bar
Restore the pressure in the heating circuit
18

Combi boiler central heating mode (CH)
C.H. Demand
Pump On iC & iS Range Error Code: 140
iR Range Error Code: 141
Pump Check by
Water Pressure - OK
Diverter Valve
CH Position
Gas Valve Start
Sequence
Fan On 612 Fan Error
No Ignition
Boiler Operating
Gas Valve Opens
Spark
Ignition
Flame ON
Flame
Stabilization
5 Seconds
Stabilization
No Flame
Detection
Boiler Will Go
To Low Load
Error code: 501
No flame
detected - Reset
5 Attempts –
Ignition Achieved
NO
NO
NO
YES
YES
YES
5 Attempts 5P1
or 5P2 - Ignition
Achieved
19

Combi boiler hot water mode (DHW)
D.H.W. Demand
Pump On Pump Check by
Water Pressure - OK
Diverter Valve
D.H.W. Position
Gas Valve Start
Sequence
Fan On 612 Fan Error
No Ignition
Boiler Operating
Gas Valve Opens
Spark
Ignition
Flame ON
Flame
Stabilization
5 Seconds
Stabilization
No Flame
Detection
D.H.W. Rated
Output
5 Attempts –
Ignition Achieved
NO
YES
YES
YES
Error code: 501
No flame
detected - Reset
NO
NO
5 Attempts 5P1
or 5P2 - Ignition
Achieved
iC & iS Range Error Code: 140
iR Range Error Code: 141
20