Geco GH11TA User manual

OPERATING MANUAL FOR
THE CONTROLLER
GH11TA
TO CONTROL
CENTRAL HEATING BOILERS
WITH PISTON FEEDER
PISTON FEEDER
Programme version
01
SERVICE MANUAL
We strongly request that you study the instructions carefully before connecting
and commissioning of each of our devices. In case of any doubt, please
please contact us between 8.00 a.m. and 4.00 p.m.

SERVICE MANUAL GH11TA PAGE 3
SPIS TREŚCI
1. INTRODUCTION ................................................................................................................................. 4
1.1. GRAPHIC DESIGNATIONS .......................................................................................................................... 4
1.2. KEYBOARD AND FUNCTION KEYS ............................................................................................................... 4
2. GENERAL CHARACTERISTICS .............................................................................................................. 5
3. TECHNICAL DATA............................................................................................................................... 5
4. ELECTRICAL INSTALLATION AND CONNECTION RULES ........................................................................ 6
5. QUICK START..................................................................................................................................... 6
6. OPERATION OF THE GH11TA.............................................................................................................. 8
6.1. HEATING SYSTEM OPERATED..................................................................................................................... 8
6.2. AUTOMATIC OPERATION MODE ................................................................................................................. 9
6.3. MANUAL OPERATION MODE ................................................................................................................... 10
6.4. TEMPERATURE PREVIEW ........................................................................................................................ 11
6.5. ALARMS .............................................................................................................................................. 11
6.6. POWER OUTAGE ................................................................................................................................... 11
6.7. BOILER EXPIRATION DETECTION ............................................................................................................... 12
6.8. FEEDER MAXIMUM TEMPERATURE DETECTION ........................................................................................... 12
7. USER SETTINGS................................................................................................................................ 13
7.1. BOILER SET TEMPERATURE (U0) .............................................................................................................. 13
7.2. FUEL FEEDER STANDSTILL TIME (U1)......................................................................................................... 13
7.3. HOLDING TIME (U2).............................................................................................................................. 13
7.4. FAN SPEED (U3) ................................................................................................................................... 14
7.5. SETPOINT TEMPERATURE OF DHW/RETURN (U4) ...................................................................................... 14
7.6. ANTI-LEGIONELLA FUNCTION (U5)........................................................................................................... 14
8. OPERATION OF THE HOT WATER BOILER.......................................................................................... 15
8.1. ASSEMBLY AND CONNECTION.................................................................................................................. 15
8.2. CONFIGURATION OF AUXILIARY PUMP ...................................................................................................... 16

8.3. DHW PRIORITY .................................................................................................................................... 16
8.4. SUMMER MODE.................................................................................................................................... 16
9. ROOM PANEL .................................................................................................................................. 17
GH11TA GA01HA............................................................................................................................... 17
10. TEMPERATURE LIMITER (STB)....................................................................................................... 18
10.1. METHOD OF OPERATION .................................................................................................................... 18
10.2. RESTARTING THE STB FUNCTION (MANUAL) .......................................................................................... 18
11. DEALING WITH DAMAGE TO THE CONTROLLER............................................................................. 19
12. CONNECTING DEVICES TO THE GH11TA CONTROLLER ................................................................... 21
13. SERVICE MODE............................................................................................................................. 22

SERVICE MANUAL GH11TA PAGE 4
1. INTRODUCTION
1.1. Graphic designations
The symbols intended to signal and at the same time emphasise the importance of the text in which the
information on the warning of a dangerous situation is contained have the following graphic form:
Warning
This symbol is used when it is necessary to follow the sequence of operations in the
described instructions. If you make a mistake or do not follow the description, the
device may be damaged or destroyed.
Important!
This symbol indicates information of special interest.

Reference
This symbol indicates the occurrence of additional information in the chapter.
1.2. Keyboard and function keys
PROGRAMMING
ON / OFF
MANUAL
MODE
AUTOMATIC OPERATION
STATUS INDICATION
MANUAL FAN ACTIVATION
/ PARAMETER VALUE CHANGE
UPWARDS
AUTO MODE
OPERATING STATUS
INDICATION IN
CONTINUOUS
MANUAL SWITCHING ON OF
THE FEEDER
/ PARAMETER VALUE CHANGE
DOWN

SERVICE MANUAL GH11TA PAGE 5
2. GENERAL CHARACTERISTICS
The GH11TA controller is made using microprocessor technology with automatic surface mounting.
This controller controls the process of preparation of usable hot water (DHW circuit) and enables operation
of the main heating circuit (CH circuit). The control parameters can be adjusted to the current operating
conditions and the type of boiler. The regulator is equipped with a protection system against power
failures and various types of interference.
The GH11TA controller is equipped with:
inputs:
1. to measure the temperature of the boiler outlet water (NTC type sensor),
2. to measure the fuel feeder temperature (NTC type sensor),
3. to measure the water temperature in the DHW boiler (NTC type sensor),
digital input:
4. to connect a pin break sensor on the feeder - reed switch
input (RS485) for the connection of room panel GA01HA by GECO
It also has four outputs enabling direct connection of devices operating at 230V, i.e.: fan, fuel feeder, CH
circulation pump, HUW pump or mixing pump, depending on the supported heating system ( p.6.1, p.8).
DISCONNECT THE CONTROLLER FROM THE MAIN SUPPLY
DURING A STORM
3. TECHNICAL DATA
Supply voltage
230V ~ +10% -15%
Resistance characteristics
for NTC-type sensors
Operating temperature
od +5°C do +40°C
Moisture
od 20% do 80% RH
Temperature
°C
Resistance

Fan protection
3,15A
0
7174,89
Sensor type
NTC 2,2k
10
4374,83
Operating range of the temperature
sensor
0°C÷100°C
20
2747,10
30
1774,91
40
1172,09
Output
Maximum
continuous load
50
795,08
60
547,95
DHW pump/mixing pump
1A
200W
70
384,62
CO Pump
1A
200W
80
275,86
Fuel feeder
2A
400W
90
202,37
Fan
1A
200W
100
149,16

SERVICE MANUAL GH11TA PAGE 6
4. ELECTRICAL INSTALLATION AND CONNECTION RULES
1. The boiler room should be equipped with a 230V/50Hz electrical installation in accordance with
the relevant regulations.
2. The electrical installation (irrespective of its type) must be terminated with a plug socket fitted
with a protective contact. The use of a socket without a protective terminal connected risks an
electric shock!!!
3. The controller must be connected to a separately routed power line protected with a suitably
selected fast fuse and a residual current circuit breaker (anti-shock).No other devices may be
connected to this line!!!
THE REGULATOR IS POWERED FROM THE MAINS 230V/50HZ ANY
REPAIRS CAN ONLY BE CARRIED OUT WITH THE POWER SUPPLY
DISCONNECTED AT THE FUSE
5. QUICK START
To perform a quick start-up of the GH11TA controller, perform the following steps:
1. Connect the device to the 230V mains (plug in the socket).

2. Switch on the controller using the button . The following screen will appear:

SERVICE MANUAL GH11TA PAGE 7
3. Press the button . The following screen will appear:
The controller will start automatic operation based on the factory-set parameters.
Table of factory settings
User
Parameter
Description
Factory
setting
U0
Prescribed boiler temperature
600C
U1
Feeder standstill time
45 s
U2
Holding time
15 min
U3
Fan speed
5

SERVICE MANUAL GH11TA PAGE 8
6. OPERATION OF THE GH11TA
6.1. Heating system operated
6.1.1. CH + DHW circuit
INPUTS
OUTPUTS
T1 –Boiler Temp.
P1 - Feeder
T2 –Feeder Temp.
P2 - Fan
T3 –CWU Temp.
P3 –CWU Pump
C1 - Contactor
P4 –CO Pump
6.1.2. CH circuit + mixing pump
INPUTS
OUTPUTS
T1 –Boiler Temp.
P1 - Feeder
T2 –Feeder Temp.
P2 - Fan
T8 –Return Temp.
P4 –CO Pump
C1 - Contactor
P8 –Mixing Pump

SERVICE MANUAL GH11TA PAGE 9
6.2. Automatic operation mode
Pressing the button enters the automatic operation mode of the controller, which is signalled by
the upper indicator light on the button ( ).
6.2.1. Fuel feeder
In automatic operation, the unit operates according to a new algorithm for feeding equal portions of fuel.
The amount of fuel fed in one feeder cycle is specified in service parameter F21.
The feeder is started every time set in parameter u1- "Feeder standstill time".
After reaching the maximum advance position, the piston is retracted until the reed switch operates, the
feeder run time is reset and the feeding cycle repeats.
After switching to AUTOMAT mode from REED MODE or after a power failure, the controller activates the
feeder until reaching the maximum position of reversal (reed switch operation), then the feeder starts
operating normally.
The feeder operation is suspended after the STOP&GO function is activated. The feeder and fan operation
is not suspended (STOP&GO) if the temperature drop is more than 6 degrees below the setpoint. In
addition, this function can be deactivated using service parameter F23.
Activation of the fuel feeder and its operation is signalled by lighting up the lower indicator on the button
(p.1.2 str.4).
6.2.2. CO Pump
In AUTOMATIC mode, the CH pump is switched on if the boiler water temperature is higher than or
equal to the value set in the F06 service parameter (factory setting is 400C).
Activation of the CH pump and its operation is signalled by the lighting up of the vertical line on the
left side of the display on the main screen of the controller.
The controller will switch off the pump if the water temperature falls to the pump cut-in
temperature minus 4oC. (If the switch-on temperature of the CH pump is 400C, then the switch-off
temperature of the CH pump is 360C).
6.2.3. Fan
In AUTOMATIC mode, the fan runs continuously until the boiler reaches the preset temperature
set by the user in parameter u0. During this time, the fan operates at its maximum speed. Activation and
operation of the fuel feeder is signalled by lighting up the upper indicator light on the button.
6.2.4. Contactron
The maximum piston retraction sensor (reed switch) in AUTOMAT mode operates according to the
value set in service parameter F19. When the time 5/4value of F19 is exceeded and the reed switch does
not operate, ALARM 9 appears. (p.Błąd! Nie można odnaleźć źródła odwołania. pg.Błąd! Nie
zdefiniowano zakładki.).

SERVICE MANUAL GH11TA PAGE 10
6.2.5. HOLD MODE
The controller switches to this operating mode if the temperature on the boiler reaches the value
set by the user in parameter u0.
This mode of boiler operation is signalled by the lighting up of the lower indicator light on the button
( ).
The fuel feeder and fan remain off in this operating mode for the time set by the user in parameter u2.
After this time, the controller will switch on the feeder and fan for the time set by the manufacturer in
service parameter F19.
The fan will run correspondingly longer than the feeder for the time set in service parameter F18 to ignite
the added coal.
The controller will exit BASIC mode and return to AUTOMAT mode if the boiler temperature drops to a
value equal to u0 - F05.
The CH pump operates in the same way as in automatic operation.
6.3. Manual operation mode
In this mode of operation, the user can manually and independently switch on and off the fuel feeder
and fan. To do this, follow the diagram below:
In the manual operation mode, it is also possible to switch on the C.O. and DHW pumps. To switch
on the C.O., press the key combination simultaneously: + . Activation of the central
heating pump and its operation is signaled by the appearance of a vertical dash on the left side of
the display on the main screen of the controller.
To turn on the DHW pump, press the key combination simultaneously: + . Activation of
the DHW pump and its operation is signaled by the appearance of a vertical dash on the left side
of the display on the main screen of the controller.
Pressing the button enters manual operation mode from automatic operation mode and immediately
stops the operation of the fan and feeder.
STEP 1
STEP 2
→
The controller
shows the
measured water
temperature on
the CO boiler.
Fuel feeder
The lower indicator light on the
button comes on .
Pressing the button again turns
off the feeder, and
extinguishes the indicator light
Fan
The top light on the button
comes on . Pressing the
button again turns off the
feeder, and extinguishes the
indicator light

SERVICE MANUAL GH11TA PAGE 11
6.4. Temperature preview
When the button is turned on the display shows the outlet water temperature
from the boiler. Viewing temperatures: DHW/return and feeder are possible in AUTOMAT and BASIC
operating modes, provided that the DHW/return or feeder sensor operation is enabled, respectively.
To preview the feeder temperature, press the button . Pressing the button again exits the
preview. It also exits the preview automatically 10s after the button is pressed.
To preview the DHW/return temperature, press the button . Pressing the button again exits the
preview. It also exits the preview automatically 10s after the button is pressed.
6.5. Alarms
The controller distinguishes between 8 alarm states. In each of them, the alarm number is displayed,
and the acoustic alarm output is activated. In case of simultaneous occurrence of several alarm states,
their numbers are displayed cyclically. Exit from the alarm state is possible only after pressing the button
.
Types of alarms:

AL1

STB tripped or fuse blown

AL2

Boiler outlet water temperature sensor failure

AL3

Feeder temperature sensor failure

AL4

Failure of DHW/return temperature sensor

AL9

No feeder rotation / faulty reed switch

AL11

Maximum feeder temperature exceeded

AL12

Overheating of the boiler

AL13

Boiler expiration
6.6. Power outage
After a power outage, the controller will take action depending on the state it was in before the power
outage. The controller waits 1 minute for the state of the power grid to stabilize, after which it returns to
operation with the previously programmed parameter values.
During the waiting time, the display shows the time in seconds remaining
to its end, and the indication of the state in which the controller was before the power outage:
The flashing letter "A" corresponds to automatic operation,
the letter "P" corresponds to sustained operation,
the letter "r" of manual operation.
Along with the letters, the corresponding lights also flash (AUTOMATIC OR HOLDING ).

SERVICE MANUAL GH11TA PAGE 12
6.7. Boiler expiration detection
6.7.1. No Fuel
If during automatic operation for the time set in parameter F09, the boiler outlet water temperature is
below the value set in parameter F08, then the controller considers that the boiler has expired and AL13
appears.
6.7.2. Rapid drop in outlet water temp
If the boiler outlet water temperature decreases by 100C during automatic operation and it does not
increase by 40C during the decrease, the CH pump and the DHW pump are turned off and the controller
enters the expiration detection mode.
The controller waits for the time set in parameter F10, during which it checks whether there has been a
40C temperature rise.
If YES, the expiration detection is completed, and the CH pump and DHW pump (if required) are switched
on.
If NO, it means that the furnace has expired - the controller reports AL13.
6.8. Feeder maximum temperature detection
The GH11TA controller is equipped with an option for additional protection against temperature rise in the
fuel feeder above the permissible value, thus preventing the flame from going back into the fuel feeder.
This detection works only in the automatic boiler operation mode (AUTOMATIC, BASIC).
When the temperature set in service parameter F14 is measured and exceeded, the fuel feeder turns on
for the time set in service parameter F16 to eject the ignited fuel from the feeder. During the F16 time, the
fan remains off.
After the time set in service parameter F15, the controller returns to control the max feeder temperature.
When temp. of the feeder > 900C then the fan is absolutely stopped, the fuel feeder is switched on for
2xF16, and the controller display shows the AL11 alarm message The controller remains in the alarm state
until the user reacts.
IF F14=0 THEN THE FEEDER SENSOR OPERATION IS DISABLED AND THE
FEEDER MAX TEMPERATURE RISE DETECTION FUNCTION DOES NOT
WORK.

SERVICE MANUAL GH11TA PAGE 13
7. USER SETTINGS
7.1. Boiler set temperature (u0)
Changes in the value of the boiler set temperature are made as follows:
7.2. Fuel feeder standstill time (u1)
This is the time between successive coal feeds to the CO boiler in AUTOMATIC mode (without taking into
account service parameter F47). The actual value of the time between fuel feeds is: U1×F47.
Its range of variation is from 5 s to 250 s.
Changing this parameter is done as follows:
STEP 1
STEP 2
STEP 3
STEP 4
→
→
lub
→
The green LED on
the button lights up.
The display shows
the value of the
parameter u0
Transition
to
parameter
u2
Setting the desired
value
from 5s to 250s
Saving
The new value
of the
parameter.
Move to
parameter u2
7.3. Holding time (u2)
This is the time after which the controller will switch on the feeder and the fan for a manufacturer-
specified time in the FIXING mode to prevent the boiler from expiring. The modification range of this
parameter is from 5 min to 250 min. Modification of this parameter is carried out in the same way as
described in p.7.1 and p.7.2.
STEP 1
STEP 2
STEP 3
→
lub
→
The green LED on the
button lights up.
The display shows the
temperature set so far
Setting the desired
temperature from the
range from 500C to 850C
Memorizing
The new temperature
value.Transition to
parameter u1
If during the setting of the new temperature for 15 seconds none
of the keys is pressed , , ,
then the new temperature will not be stored and the controller
will exit programming mode.

SERVICE MANUAL GH11TA PAGE 14
7.4. Fan speed (u3)
This parameter determines the speed of the fan, that is, the amount of air supplied. It allows you to select
the fan speed according to the quality and type of fuel used.
The value of this parameter can be changed in the range 1 10 , where "1" means the minimum speed,
and "10" is the maximum.
Modification of this parameter is carried out in the same way as described in
in p.7.1 and p.7.2.
7.5. Setpoint temperature of DHW/return (u4)
This parameter is available to the user only if the user uses the
the domestic hot water (DHW) heating or return temperature stabilization option and has configured
the auxiliary pump by setting service parameter F00 to "01"' "02", "03" or "04" (p.8.2 page 17).
Modification of this parameter is carried out in the same way as described in p.7.1 and p.7.2.
7.6. Anti-Legionella function (u5)
The GH11TA controller is equipped with an ANTI-LEGIONELLA function to reduce the growth of Legionella
pneumophilia bacteria in the hot water system. This function is available to the user only if the value of
service parameter F00 has been set to "02", "03" or "04" (p.0 p.17).
Legionella bacteria thrive in an aqueous environment, and the optimum for their growth is at 38-420C. The
growth of these bacteria is also favored by stagnant hot water in systems, heaters and DHW tanks.
Legionella bacteria cause a non-specific form of pneumonia known as Legionnaires' disease, or
Legionellosis. Legionellosis has been officially recognized by the Ministry of Health as an infectious disease.
The ANTI-LEGIONELLA function implemented by the GH11TA controller on ensure the creation of a
in the domestic hot water system (DHW tank) such conditions that Legionella bacteria do not find
favorable living conditions.
In order to activate the ANTI-LEGIONELLA function, parameter u5 should be set to 1.
Activation of this function and its duration is shown by the flashing letter "L" on the left side of the display,
before the displayed temperature value.
Deactivation of this function is possible by setting the value of the parameter u5=0 or by pressing the
button . The Anti-Legionella function also terminates when the power supply fails.
The Anti-Legionella function is an overriding function, which means that it is executed by the controller
first (priority function).
When this function is activated, the water temperature in the boiler is raised to 700C
and is maintained for a period of 10 minutes.
ACTIVATING THE ANTI-LEGIONELLA FUNCTION INCREASES THE HOT
WATER TEMPERATURE TO 700C .
USE EXTREME CAUTION WHEN USING HOT WATER.
YOU MAY RISK SCALDING !!!

8. OPERATION OF THE HOT WATER BOILER
GH11TA controller allows you to connect an additional pump to control the heating of domestic hot
water (DHW) in the boiler.
8.1. Assembly and connection
If you want to use the domestic hot water (DHW) heating option, perform the following steps:
1. connect the boiler according to the attached diagram (p.6.1.1 p.8).
2. place the DHW temperature sensor inside the boiler
It is recommended to install the DHW temperature sensor in the
measuring wells of the company "GECO" Ltd.
It is absolutely forbidden to place temperature sensors in wells with oil
or other liquid !!!
3. connect the DHW temperature sensor to the controller under the terminals as shown in
Figure 2.
4. configure the operation of the DHW pump (p.8.2 p.17).
The DHW temperature sensor is an additional sensor (option), not
supplied with the GH11TA controller.
It is possible to purchase the aforementioned sensor for an additional
fee from the manufacturer, i.e. "GECO" Sp. z o.o.

SERVICE MANUAL GH11TA PAGE 16
8.2. Configuration of auxiliary pump
In this parameter, the user has the option to switch on the operation of an additional pump, which can
be a mixing pump or a DHW pump operating with or without priority mode.
The DHW pump is switched on when the boiler outlet water temperature is higher than 400C
and higher than the boiler water temperature (in order not to cool down the DHW boiler) and the boiler
temperature is lower than the one set by the user in parameter u4 (p.7.5 p.15).
The indication of the pump operation is a dot next to the fan symbol on the display.
In the case of the boiler room configuration as shown in the diagram (p.6.1.1 p.8), the boiler
controller does not have an external alarm output, but has the ability to view the DHW boiler temperature
To switch on in the controller support for an additional pump, proceed as follows:
STEP 1
STEP 2
STEP 3
STEP 4
→
→
lub
→
Display shows
„─ ─ ─ ─”
Hold for 2s
Set the desired value of F00
00 –no pump operation
01 –mixing pump
02 –DHW pump winter without priority
03 –Winter DHW pump with priority
04 –DHW pump summer (summer
mode)
Remembering
new
value
8.3. DHW priority
In the GH11TA controller it is possible to set the operation of the DHW pump in priority mode.
If you select such a mode of operation of the DHW pump, DHW heating becomes the overriding function in
the controller.
To do this, set the value "3" of service parameter F00.
8.4. Summer mode
The GH11TA controller is equipped with the so-called SUMMER MODE, with the help of which it is possible
to disable the CH pump for the summer period, and the boiler works only for the needs of DHW.
To do this, set the value "4" of service parameter F00.

SERVICE MANUAL GH11TA PAGE 17
9. Room Panel
The GH11TA regulator has been adapted for full communication with GECO's GA01HA room panel,
enabling comfortable supervision of boiler operation from the apartment.
The room panel GA01HA connected to the GH11TA controller allows:
change the preset temperature of the boiler (u0)
change the preset DHW temperature (u4)
appearance on the room panel of information about all alarms
preview of boiler operation status
preview of device operation status (fan, CH pump, HUW pump)
preview of all measured temperatures
If a GA01HA room panel is properly connected to the GH11TA controller, it will be automatically detected
by the controller and no additional actions or settings are required on the part of the user.
In this situation, the controller operates according to the settings set by the room panel.
Disconnection of the room panel (interruption of communication) or damage to the cable connecting the
panel to the controller is manifested by the disappearance of the "dot" on the last display 30s after the
panel is disconnected.
In order to connect the GA01HA room panel to the GH11TA controller, it is necessary:
STEP 1
STEP 2
STEP 3
STEP 4
STEP 5
Turn off the
controller with
the
button
and remove the
plug from the
mains cable
from the socket
→
Open the
controller
(remove the
top cover of
the housing)
→
Connect the
room panel to
the controller
at terminals
A-B-C-D as
shown in
picture 1.
→
Snap the top
cover of the
controller
housing (close
the
controller)
→
Insert the plug of the
power cord into the
230V socket
and turn the
controller on with
the button
GH11TA GA01HA
Picture. 1 Connection diagram of room panel GA01HA to controller GH11TA
THE FACT THAT THE CONTROLLER OPERATES ACCORDING TO THE
SETTINGS OF THE ROOM PANEL IS INDICATED BY THE LIGHTING OF A
DOT ON THE LAST DISPLAY

SERVICE MANUAL GH11TA PAGE 18
10. TEMPERATURE LIMITER (STB)
The GH11TA controller is equipped with additional mechanical protection, independent of the
automation, called a safety temperature limiter (STB).
10.1.Method of operation
If the heating water reaches the temperature 950Cthe temperature limiter will operate automatically
(activate the STB function) and interrupt the fuel supply and combustion air supply (turn off the fuel feeder
and fan).
When the temperature on the limiter drops by about 200Cit will be possible to activate the STB
function again, only manually.
10.2.Restarting the STB function (manual)
To restart the device, press the "RESET" button located
on the left side of the controller housing.
For safety reasons, the controller does not automatically return to automatic operation.
To return the controller to work again, press the button twice :
- the first press of the button will cancel the alarm and turn off the controller
- a second press of the button will restart the controller
- press - the controller will go into automatic operation mode
PUNCTURE OR BREAKAGE OF THE CAPILLARY MEANS LEAKAGE OF THE
TEMPERATURE LIMITER FILLED WITH LIQUID, WHICH LEADS TO
INCORRECT OPERATION OF THE GH11TA CONTROLLER.
IF THE DESCRIBED MALFUNCTION IS FOUND, THE TEMPERATURE
LIMITER SHOULD BE DISCONNECTED FROM THE GH11TA CONTROLLER,
REMOVED AND REPLACED WITH A NEW UNIT.

SERVICE MANUAL GH11TA PAGE 19
11. DEALING WITH DAMAGE TO THE CONTROLLER
If you notice any irregularities in the operation of the controller, it is advisable to contact the boiler
supplier/manufacturer or GECO Ltd.
Professional technical advice will be provided there.
If you find it necessary to take service action to repair the controller, you should dismantle the damaged
controller from the boiler and send the complete controller, including the casing, to the indicated address.
SENDING AN INCOMPLETE CONTROLLER TO THE SERVICE WILL
AUTOMATICALLY VOID THE WARRANTY
PREPARING THE CONTROLLER TO BE SENT FOR SERVICE
STEP 1
Disconnect the controller
from the power supply voltage
(remove the plug from the socket)
STEP 2
Remove the front panel
using flathead screwdriver

SERVICE MANUAL GH11TA PAGE 20
STEP 3
Remove the housing cover
by undermining the latches
using
flathead screwdriver
STEP 4
Remove the plug connectors with
connected wires from the sockets,
unscrew the ground wires from the PE
strip, loosen the wire clamping strip and
remove all the wires outside the
controller
STEP 5
Remove the controller from the boiler by
unscrewing the 4 mounting screws
in the lower part of the
housing of the controller
STEP 6
Replace the top cover of the housing
and the front panel