Webasto RHA-100, RHA-101, RHA-102 Workshop Manual
Air heaters
Integrated heater
10/2009
9019782B
03/2003
Workshop Manual
Dual Top RHA-100
Dual Top RHA-101/102
Improper installation or repair of Webasto heating and cooling systems can cause fire or the
leakage of deadly carbon monoxide leading to serious injury or death.
To install and repair Webasto heating and cooling systems you need to have completed a
Webasto training course and have the appropriate technical documentation, special tools and
special equipment.
NEVER try to install or repair Webasto heating or cooling systems if you have not completed a
Webasto training course, you do not have the necessary technical skills and you do not have
the technical documentation, tools and equipment available to ensure that you can complete
the installation and repair work properly.
ALWAYS carefully follow Webasto installation and repair instructions and heed all WARNINGS.
Webasto rejects any liability for problems and damage caused by the system being installed by
untrained personnel.
Dual Top Table of Contents
I
Table of Contents
1 Introduction .......................................................................................................................101
1.1 Contents and purpose .............................................................................................................................101
1.1.1 Use of the integrated heaters ........................................................................................................101
1.2 Meaning of signal words .........................................................................................................................101
1.3 Additional documentation to be used .....................................................................................................101
1.4 Statutory regulations and safety instructions ...........................................................................................101
1.4.1 Statutory regulations governing installation ...................................................................................101
1.4.2 General safety information ............................................................................................................101
2 Technical data ...................................................................................................................201
3 Fault code output ..............................................................................................................301
3.1 Manual Control Panel .............................................................................................................................301
3.2 Programmable Control Panel ...................................................................................................................304
4 Function tests ....................................................................................................................401
4.1 General ...................................................................................................................................................401
4.2 Repair Shop Level Testing ........................................................................................................................401
4.2.1 Testing individual components ......................................................................................................401
4.2.1.1 Glowplug resistance test ...................................................................................................401
4.2.1.2 Air temperature sensor resistance test ...............................................................................401
4.2.1.3 Water temperature sensor resistance test ..........................................................................401
4.2.1.4 Air temperature switch .....................................................................................................402
4.2.1.5 Water temperature switch ................................................................................................402
4.2.1.6 Overheating protector .......................................................................................................402
5 Circuit diagrams ................................................................................................................501
5.1 General ...................................................................................................................................................501
5.2 Legend for circuit diagram ......................................................................................................................508
6 Servicing work ..................................................................................................................601
6.1 General ...................................................................................................................................................601
6.2 Work on the heater .................................................................................................................................601
6.3 Work on the vehicle ................................................................................................................................601
6.4 Heater test run ........................................................................................................................................601
6.5 Servicing work ........................................................................................................................................601
6.6 Visual inspections and installation instructions .........................................................................................601
6.7 Removal and installation .........................................................................................................................601
6.7.1 Heater, removal and installation ....................................................................................................601
6.7.1.1 Removal ............................................................................................................................601
6.7.1.2 Installation ........................................................................................................................602
6.7.2 Control Panel, removal and installation .........................................................................................602
6.7.2.1 Manual version (for RHA 100) ...........................................................................................602
6.7.2.2 Programmable version (for RHA 100/101/102) ..................................................................602
6.7.2.3 Installation ........................................................................................................................602
6.8 Start-up ..................................................................................................................................................602
Table of Contents Dual Top
II
7 Repair .................................................................................................................................701
7.1 General .................................................................................................................................................. 701
7.1.1 Work on stripped-down components ........................................................................................... 701
7.1.1.1 Cleaning .......................................................................................................................... 701
7.1.1.2 Visual inspection .............................................................................................................. 701
7.2 Dismantling ............................................................................................................................................ 701
7.3 Assembling ............................................................................................................................................ 708
7.4 Replacement of older to newer type Dual Top RHA 100 ......................................................................... 715
8 Packaging, storage and shipping .....................................................................................801
8.1 General .................................................................................................................................................. 801
Dual Top 1 Introduction
101
1 Introduction
1.1 Contents and purpose
This workshop manual is designed to assist trained personnel with repairing the Dual Top integrated heaters.
1.1.1 Use of the integrated heaters
The Webasto Dual Top integrated air / water heaters are designed to heat and to provide hot water in motor homes
and similar vehicles.
The heaters operate independently of the engine and are
connected to the fuel tanks and the service battery of the
vehicle.
The heaters are not designed for heating vehicles transporting hazardous substances.
1.2 Meaning of signal words
Throughout this manual, the signal words WARNING, IMPORTANT and NOTE have the following meanings:
WARNING
This heading is used to highlight operating instructions or
procedures which, if not or not correctly followed, may result in personal injury or fatal accidents.
IMPORTANT
This heading is used to highlight operating instructions or
procedures which, if not or not correctly followed, may result in damage to the equipment or its components.
NOTE
This heading is used to direct your attention to a special feature deemed essential to highlight.
1.3 Additional documentation to be used
This workshop manual contains most of the information
and instructions required for repairing the Dual Top integrated heaters.
However, it is necessary to read additional documentation.
The operating / installation instructions and the installation
suggestion for the specific vehicle (if available) shall also be
used.
1.4 Statutory regulations and safety
instructions
In principle, the general accident prevention regulations and
current works safety instructions are applicable. The "General safety regulations" that go beyond the scope of the
above regulations are stated below.
Any special safety regulations relevant to this instruction
manual will be highlighted in the relevant sections or text
passages of the procedures.
1.4.1 Statutory regulations governing installation
The Dual Top heaters have been type-tested and approved
in accordance with EC Directives 72/245/EEC (EMC) and
2001/56/EC (heater) with the following EC permit numbers:
e1 03 5000
e1 00 0195.
Installation is governed above all by the provisions in Annex
VII of Directive 2001/56/EC and the regulations in the installation instructions.
NOTE
The provisions of these Directives are binding within
the territory governed by EU Directive 70/156/EEC and/
or 2007/46/EC should similarly be observed in countries without specific regulations!
Installation of the Dual Top RHA 101/102 heater and related
components must be in accordance with IEC 60364 (“Electrical installations in caravan parks and caravans”).
IMPORTANT
Dual Top RHA 101/102: you have to be certified to work on
230 V electric systems. Installation and all other jobs carried
out by none certified persons can cause personal injury to
you, the Dual Top and the vehicle. In that case, Webasto will
refuse all liability.
IMPORTANT
Failure to follow the installation instructions and the notes
contained therein will lead to all liability being refused by Webasto. The same applies if repairs are carried out incorrectly or
with the use of parts other than genuine spare parts. This will
result in the invalidation of the type approval for the heater
and therefore of its
homologation / EC type licence
.
NOTE
For vehicles with an EU permit, no entry in accordance with
§ 19 Sub-Section 4 of Annex VIII b to the Road Traffic Act is
required.
1.4.2 General safety information
Follow all the safety information described in the additional
documentation thoroughly.
1 Introduction Dual Top
102
Dual Top 2 Technical data
201
2Technical data
Except where limit values are specified, the technical data
refer to the usual heater tolerances of ± 10 % at an ambient
temperature of + 20 °C and at the rated voltage and in rated
conditions.
Fuel for Dual Top
The diesel fuel specified by the manufacturer must be used.
Class EL heating oil, L heating oil or PME (bio-diesel) must
not be used.
Fuel additives have no negative influences on the heater. If
fuel is extracted from the vehicle‘s tank, follow the additive
instructions issued by the vehicle manufacturer.
After changing to low-temperature fuel, the heater must be
operated for approx. 15 minutes so that the fuel system is
filled with the new fuel.
Table 201: Technical data RHA 100
Heater Operation Dual Top RHA 100
Type approval
heater:
EMC:
e1 00 0195
e1 03 5000
Model Air heater with evaporator burner
Heat output Control range 1.5 - 6.0 kW
Fuel Diesel, DIN/EN 590
Fuel consumption Control range 0.17 - 0.65 l/h
Rated voltage 12 V
Operating voltage range 10.5 - 15 V
Current input at 12V Summer mode
Winter mode, heat and hot
water
Stand-by
< 1 A
0.5 ~ 7 A
0.001 A
Rated power consumption Control range 15 - 65 W (EN 1646)
Max. ambient temperature:
Heater:
- Operation
- Storage
Control Panel:
- Operation
- Storage
-30 ~ +50 °C
-40 ~ +85 °C
-30 ~ +75 °C
-40 ~ +85 °C
Max. altitude (guaranteed function) 2,200 m
Adjustment range for interior temperature Control range +5 ~ +35 °C
Delivery rate for hot air (free blowing without
warm-air duct)
Maximum 200 m
3
/h
CO
2
in exhaust gas (permitted function range) 2 kW
6 kW
5.0 ~ 8.0
9.0 ~ 13
Water capacity 11 l
Water system pressure max. 3,5 bar
Overpressure valve 4.0 bar
Pressure water pump, central water supply Maximum 2.5 bar
Heater dimensions Length: 530 ± 2 mm
Width: 352 ± 1 mm
Height: 256 ± 1 mm
Weight (w/o water contents) 20 kg
2 Technical data Dual Top
202
Table 202: Technical data RHA 101/102
Heater Operation Dual Top RHA 101 Dual Top RHA 102
Type approval
heater:
EMC:
e1 00 0195
e1 03 5000
e1 00 0195
e1 03 5000
Model Air heater with
evaporator burner
and electric heating
device
Air heater with
evaporator burner
and electric heating
device
Heat output
diesel
electric
Control range 1.5 - 6.0 kW
0.6 - 1.2 kW
1.5 - 6.0 kW
1.0 - 2.0 kW
Fuel Diesel, DIN/EN 590 Diesel, DIN/EN 590
Fuel consumption Control range 0.17 - 0.65 l/h 0.17 - 0.65 l/h
Rated voltage 12 V 12 V
Operating voltage range 10.5 - 15 V 10.5 - 15 V
Current input at 12V Summer mode
Winter mode, heat and hot
water
Stand-by
< 1 A
0.5 ~ 7 A
0.001 A
< 1 A
0.5 ~ 7 A
0.001 A
Rated power consumption Control range 15 - 65 W (EN 1646) 15 - 65 W (EN 1646)
Max. ambient temperature:
Heater:
- Operation
- Storage
Control Panel:
- Operation
- Storage
-30 ~ +50 °C
-40 ~ +85 °C
-25 ~ +50 °C
-40 ~ +85 °C
-30 ~ +50 °C
-40 ~ +85 °C
-25 ~ +50 °C
-40 ~ +85 °C
Max. altitude (guaranteed function) 2,200 m 2,200 m
Adjustment range for interior
temperature
Control range +5 ~ +35 °C +5 ~ +35 °C
Delivery rate for hot air (free blowing
without warm-air duct)
Maximum > 200 m
3
/h > 200 m3/h
CO
2
in exhaust gas (permitted
function range)
2 kW
6 kW
5.0 ~ 8.0
9.0 ~ 13
5.0 ~ 8.0
9.0 ~ 13
Water capacity 11 l 11 l
Water system pressure max. 3,5 bar max. 3,5 bar
Overpressure valve 4.0 bar 4.0 bar
Pressure water pump, central water
supply
Maximum 2.5 bar 2.5 bar
Heater dimensions Length: 530 ± 2 mm
Width: 352 ± 1 mm
Height: 256 ± 1 mm
Length: 530 ± 2 mm
Width: 352 ± 1 mm
Height: 256 ± 1 mm
Weight (w/o water contents) 21 kg 21 kg
Dual Top 3 Fault code output
301
3 Fault code output
NOTE
This chapter describes the fault codes given out by the manual and programmable Control Panels.
Replacement of parts, dismantling and assembly (e.g. for inspection and cleaning) is described in chapter 7: "Repair".
3.1 Manual Control Panel
Abb. 301 Manual Control Panel
The manual Control Panel is used for RHA 100 heaters only.
The heater is able to identify faults on individual
components and during the operation.
The Control Panel gives out the fault code in a flashing
mode.
After a series of 5 fast GREEN flashes, the fault code output
will be a repeated sequence of long RED flashes. After that,
again there will be 5 fast GREEN flashes. This process is
repeated until the heater is switched off. The meaning of
the number of red flashes is shown in: Table 301: "Fault
messages manual Control Panel".
Rectify the cause of the fault.
To reset the fault, switch the heater off (at least 5 seconds)
and then turn back on.
If serious malfunctions such as overheating or failure to start
reoccur, the heater is locked and can be put back into service by deleting the failures.
Do this by disconnecting the power supply (e.g. by removing
all 3 fuses in this sequence: 5A, 10A, 15A; inserting the fuses in reversed order), while the appliance is switched on (see
Operating Instructions, mode selector knob in position 1, 2,
3, 4 or 5), but the heater is not running (to be judged by the
sound of the heater).
Deleting failures can also be done with the Webasto Thermo
Test PC-Diagnosis.
If a fault occurs, the heater stops. In case of electrical safety/
drain valve fault (17 red flashes), heating of the interior is
still possible.
Fig. 302 Example of fault code
LED
“n” x red 5 x green5 x green
1“n”2
3 Fault code output Dual Top
302
Table 301: Fault messages manual Control Panel
Number of
RED flashes
Meaning Remedy
00 No communication between Control Panel and
heater, or error Control Panel
1 First, remove fuses 15A and 5A. Then put in fuse 15A,
followed by fuse 5A.
2 Check connections of Control Panel.
3 Check fuse 15A.
4 Check wiring harness.
5 Replace Control Panel (see chapter 6: "Servicing
work").
6 Replace control unit.
01 No start (after 2 attempts to start) 1 Check fuel supply (enough fuel, at least 8 ltr.; check
fuel connection and tubes), reset heater (by switching
off for at least 30 sec.).
2 Clean burner insert.
02 Flame failure (at least > 3) 1 Check fuel supply (enough fuel, at least 8 ltr.; check
fuel connection and tubes), reset heater (by switching
off for at least 30 sec.).
2 Clean burner insert.
03 Under voltage or over voltage Charge battery or connect to another power source (DC,
12V or charger 230V),
reset heater (by switching off for at least 5 sec.)
04 Fuel pump disconnection / short circuit /
overheating
1 Check fuel pump cable and connectors.
2 Check internal wiring harness connections Y9, Y10.
05 Hot air motor fault: disconnection / short circuit
/ fan speed out of range / fan blocked
1 Let heater cool down.
Check power supply:
Fuse correct (fuse not damaged, 10A fuse used for
PWM module) and functioning.
All contacts are correct (no corrosion).
Voltage correct (>12V).
Restart heater.
2 Start blower: component test in diagnostic mode.
Run blower 5 minutes at 80%.
Listen if there is any unusual noise (grinding, etc.).
Restart heater.
3 Dismount application parts until the fan is visible.
Check if dirt, screws, objects or deformations block
the fan.
Check fan clearance with your finger (no high force!).
Remove all matters that block the fan.
Restart heater.
4 Remove service cap.
Check all electrical connectors.
Moisture in connectors (2-pin connector and 4-pin
connector)?
Moisture in connectors or on PWM module?
PWM module dark or burned?
12V power supply permanently available at PWM
module? (measure voltage between brown and red/
blue cable contacts of 4-pin connector) If not, check
external wiring harness: routing wiring harness and
pins of 12 pin connector.
In case there is a bad connector, bad wiring harness or
defect PWM module: replace defect part.
5 If heating air blower assy and wiring harness have
been checked and Dual Top still doesn’t run: replace
complete Dual Top.
06 Overheating or exceeding gradient water
temperature sensor
1 Check water level, reset heater (by switching off for at
least 5 sec.) or select winter mode without hot water
production.
2 Check fuel pump cable and connectors.
3 Check if hot and cold water pipes have been
connected correctly.
4 Check internal wiring harness connections Y9, Y10.
Dual Top 3 Fault code output
303
Note:
n/a = not available
07 Overheating or exceeding gradient hot air
temperature sensor
1 Ensure that hot air can flow freely, air intake and
outlets are not blocked.
Reset heater (by switching off for at least 5 sec.)
2 Check fuel pump cable and connectors.
3 Check internal wiring harness connections Y9, Y10.
4 Check correct assembly of hot air temperature sensor.
08 Overheating of heaters' control unit Ensure that cooling air can flow freely,
reset heater (by switching off for at least 5 sec.)
09 Combustion air motor fault: disconnection /
short circuit / overload / blocked
1 Ensure that cooling fan can freely rotate,
remove possible blocking objects.
2 Check fuse 15 A.
3 Check connector Y1 at control unit.
4 Change Drive Assy.
10 Control unit fault / heater locked 1 Put heater back into service (see beginning of this
section) and restart heater.
2 Replace control unit.
11 Interior temperature sensor disconnection or
short circuit
1 Check routing of cable, ensure that it is not pinched or
crushed,
check the connector behind the control panel.
Reset heater (by switching off for at least 5 sec.)
2 Replace interior temperature sensor.
12 Hot air temperature sensor disconnection /
short circuit
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check resistance of hot air temperature sensor.
3 Reset heater (by switching off for at least 5 sec.)
4 Replace sensor wiring harness.
13 Water temperature sensor disconnection /
short circuit
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check resistance of water temperature sensor.
3 Reset heater (by switching off for at least 5 sec.)
4 Replace sensor wiring harness.
14 Glow plug / flame detector disconnection /
short circuit
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check resistance of glowplug.
3 Reset heater (by switching off for at least 5 sec.)
4 Replace burner (incl. glowplug and evaporator
housing assy).
15 Early flame detection See fault message 14.
16 n/a n/a
17 Electrical safety/drain valve disconnection /
short circuit
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check function of solenoid valve with separate
12V DC power supply.
3 Reset heater (by switching off for at least 5 sec.)
4 Replace solenoid valve.
Table 301: Fault messages manual Control Panel
Number of
RED flashes
Meaning Remedy
3 Fault code output Dual Top
304
3.2 Programmable Control Panel
Fig. 303 Programmable Control Panel
The programable Control Panel can be used with all types
Dual Top heaters.
The heater is able to identify faults on individual
components and during the operation.
The Control Panel gives out the fault message.
Rectify the cause of the fault.
To reset the fault, confirm message by pressing OK (if
provided) or switch off the Dual Top for at least 5 seconds.
If serious malfunctions such as overheating or failure to start
reoccur, the heater is locked and can be put back into
service by deleting the failures.
Do this by disconnecting the power supply:
Ensure that the heater/ventilator is not running (to be
established by the sound of the heater operating).
If necessary wait until ventilators stop running.
Switch off Dual Top by pressing on/off button.
Remove all 3 fuses in this sequence: 5A, 10A, 15A; insert
the fuses in reversed order after at least 5 seconds.
Now the heater is reset.
Deleting failures can also be done with the Webasto Thermo
Test PC-Diagnosis.
If a fault occurs, the heater stops. Failure of drainage valve
(message 28 and 29) will not abort heater operation and will
not be shown during heater operation.
Table 302: Fault messages programmable Control Panel
Message Meaning Remedy
Message 01
No data connection
No communication between
Control Panel and heater, or error
Control Panel.
1 First, remove fuses 15A and 5A. Then put in fuse 15A,
followed by fuse 5A.
2 Check connections of Control Panel.
3 Check fuse 15A.
4 Check wiring harness.
5 Replace Control Panel (see chapter 6: "Servicing
work").
6 Replace control unit.
Message 02
No start of combustion
No start (after 2 attempts to start) 1 Check fuel supply (enough fuel, at least 8 ltr.; check
fuel connection and tubes), reset heater (by switching
off for at least 30 sec.).
2 Clean burner insert.
Message 03
Combustion interrupted
Flame failure. Restart not successful See message 02.
Message 04
High battery voltage
Operation voltage is above
permitted value
Reset heater (by pressing OK or switching off for at least
5 sec.)
Message 05
Low battery voltage
Operation voltage is below
permitted value
Charge battery or connect to main power supply (230V),
reset heater (by pressing OK or switching off for at least
5 sec.)
Message 06
Fuel pump disconnected
or system overheated
Fuel pump disconnection / one of
the three overheating switches
detects too high temperature
OR relaybox, cable or connection
relaybox is defective
1 Check fuel pump cable and connectors.
2 Check internal wiring harness connections Y9, Y10.
RHA 101/102 additionally:
1 Check wiring harness relaybox to heater.
2 Check relaybox and connections relaybox.
Message 07
Fuel pump short circuit
Fuel pump short circuit to ground
OR relaybox, cable or connection
relaybox is defective
See message 06.
Dual Top 3 Fault code output
305
Message 08
Failure heating air
ventilator
Hot air motor fault: disconnection /
short circuit / fan speed out of range
/ fan blocked
1 Check power supply:
Fuse correct (fuse not damaged, 10A fuse used for
PWM module) and functioning.
All contacts are correct (no corrosion).
Voltage correct (>12V).
Restart heater.
2 Start blower: component test in diagnostic mode.
Run blower 5 minutes at 80%.
Listen if there is any unusual noise (grinding, etc.).
Restart heater.
3 Dismount application parts until the fan is visible.
Check if dirt, screws, objects or deformations block
the fan.
Check fan clearance with your finger (no high force!).
Remove all matters that block the fan.
Restart heater.
4 Remove service cap.
Check all electrical connectors.
Moisture in connectors (2-pin connector and 4-pin
connector)?
Moisture in connectors or on PWM module?
PWM module dark or burned?
12V power supply permanently available at PWM
module? (measure voltage between brown and red/
blue cable contacts of 4-pin connector) If not, check
external wiring harness: routing wiring harness and
pins of 12 pin connector.
In case there is a bad connector, bad wiring harness or
defect PWM module: replace defect part.
5 If heating air blower assy and wiring harness have
been checked and Dual Top still doesn’t run: replace
complete Dual Top.
Message 09
Failure ventilator
amplifier
No communication between
amplifier of heating air ventilator
and heaters control unit
1 Check internal cable routing (4-pins) from control unit
to PWM module.
2 Replace heating air blower assy.
3 Replace thermo unit.
Message 10
High temperature
sanitary water
Overheating water temperature
sensor
1 Check water level, reset heater (by pressing OK or
switching off for at least 5 sec.) or select winter mode
without hot water production.
2 Check fuel pump cable and connectors.
3 Check internal wiring harness connections Y9, Y10.
Message 11
High temperature
sanitary water
Exceeding gradient water
temperature sensor
1 See message 10.
2 Check if hot and cold water pipes have been
connected correctly.
Message 12
High temperature
heating air
Overheating hot air temperature
sensor
1 Ensure that hot air can flow freely, air intake and
outlets are not blocked.
Reset heater (by pressing OK or switching off for at
least 5 sec.)
2 Check fuel pump cable and connectors.
3 Check internal wiring harness connections Y9, Y10.
4 Check correct assembly of hot air temperature sensor.
Message 13
High temperature
heating air
Exceeding gradient hot air
temperature sensor
See message 12.
Message 14
Failure cooling air
ventilation
Overheating of heaters' control unit Ensure that cooling air can flow freely,
reset heater (by pressing OK or switching off for at least
5 sec.)
Message 15
Failure combustion air
motor
Combustion air motor interrupted 1 Ensure that cooling fan can freely rotate,
remove possible blocking objects.
2 Check fuse 15 A.
3 Check connector Y1 at control unit.
4 Change Drive Assy.
Message 16
Failure combustion air
motor
Combustion air motor fault:
disconnection / short circuit /
overload / blocked
See message 15.
Table 302: Fault messages programmable Control Panel
Message Meaning Remedy
3 Fault code output Dual Top
306
Message 17
Failure control unit
Control unit (heater) fault / heater
locked
1 Put heater back into service (see above this table) and
restart heater.
2 Replace control unit.
Message 18
Failure cabin temperature
sensor
Interior temperature sensor
disconnection / short circuit
1 Check routing of cable, ensure that it is not pinched or
crushed,
check the connector behind the control panel.
Reset heater (by pressing OK or switching off for at
least 5 sec.)
2 Replace interior temperature sensor.
Message 19 n/a n/a
Message 20
Failure heating air
temperature sensor
Hot air temperature sensor
disconnection
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check resistance of hot air temperature sensor.
3 Reset heater (by pressing OK or switching off for at
least 5 sec.)
4 Replace sensor wiring harness.
Message 21
Failure heating air
temperature sensor
Hot air temperature sensor short
circuit
See message 20.
Message 22
Failure sanitary water
temperature sensor
Water temperature sensor
disconnection
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check resistance of water temperature sensor.
3 Reset heater (by pressing OK or switching off for at
least 5 sec.)
4 Replace sensor wiring harness.
Message 23
Failure sanitary water
temperature sensor
Water temperature sensor short
circuit
See message 22.
Message 24
Failure glow plug
Glow plug / flame detector
disconnection
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check resistance of glowplug.
3 Reset heater (by pressing OK or switching off for at
least 5 sec.)
4 Replace burner (incl. glowplug and evaporator
housing assy).
Message 25
Failure glow plug
Glow plug / flame detector short
circuit
See message 24.
Message 26
Failure flame detection
Early flame detection See message 24.
Message 27
Failure relay box
Short circuit of 230V indication
signal from relay box to heater
1 Check wiring harness relaybox to heater.
2 Check the relay box and wiring connections.
3 Check Control Panel and connections Control Panel.
4 Check internal wiring harness connections Y9, Y10.
Message 28
Failure drain valve
Electrical drainage valve
disconnection
1 Check routing of cable, ensure that it is not pinched or
crushed, check the connectors.
2 Check function of valve with separate 12V DC power
supply.
3 Reset heater (by pressing OK or switching off for at
least 5 sec.)
4 Replace solenoid valve.
Message 29
Failure drain valve
Electrical drainage valve short circuit See message 28.
Message 30
Failure relay
230V high or low power relay circuit
interrupted / short circuit
See message 27.
Message 31, 32, 33 n/a n/a
Table 302: Fault messages programmable Control Panel
Message Meaning Remedy
Dual Top 3 Fault code output
307
Note:
n/a = not available
Message 34
System overheated or
relay circuit disconnected
One of the three overheating
switches detects too high
temperatures / overheating relay
circuit interrupted
RHA 101/102:
1 Check wiring harness relaybox to heater.
2 Check the relay box and wiring connections.
3 Check Control Panel and connections Control Panel.
4 Check internal wiring harness connections Y9, Y10.
All:
1 Check for overheating (see messages 10, 11, 12, 13
and 14).
2 Reset heater (by pressing OK or switching off for at
least 5 sec.)
Message 35
Failure relay box
230V overheating relay short circuit See message 27.
Message
36, 37, 38, 39, 40, 41
n/a n/a
Message 42
Failure 230V heating
element
Electric heating device 230V defect.
No relevant temperature increase
detected.
1 Check water system for a permanent open hot water
tap OR heavy leakages.
2 Check cable 230V from relaybox to heater and
corresponding connectors.
3 Check electrical element heaters.
Table 302: Fault messages programmable Control Panel
Message Meaning Remedy
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