Rotex GSU 320 User manual

For the owner
ROTEX GasSolarUnit
Gas condensing boiler with stratified solar storage tank
Operating instructions
Type Rated thermal output
ROTEX GSU 320 3 - 20 kW modulating
ROTEX GSU 520S 3 - 20 kW modulating
ROTEX GSU 530S 7 - 30 kW modulating
ROTEX GSU 535 8 - 35 kW modulating
Manufacture number
Customer
0085 BM 0065  GB
Edition 09/2007

Guarantee and conformity
2BA ROTEX GSU - 09/2007
ROTEXaccepts the guaranteeformaterial and manufacturingdefects accordingtothisstatement. Within theguarantee period,
ROTEX agrees to have the device repaired by a person assigned by the company, free of charge.
ROTEX reserves the right to replace the device.
The guarantee is only valid if the device has been used properly and it can be proved that it was installed properly by an expert
firm.Asproof,westronglyrecommendcompletingtheenclosedinstallationandinstructionforms andreturningthem to ROTEX.
Guarantee period
The guarantee period begins on the day of installation (billing date of the installation company), however at the latest 6 months
after the date of manufacture (billing date). The guarantee period is not extended if thedevice is returned for repairs or if the
device is replaced.
Guarantee periodof the burner, of the boiler body and of the boiler electronics: 2 years
Guarantee exclusion
Improper use, intervention in the device and unprofessional modifications immediately invalidate the guarantee claim.
Dispatch and transport damage are excluded from the guarantee offer.
The guarantee explicitly excludes follow-up costs, especially the assembly and disassembly costs of the device.
There is no guaranteeclaim for wear parts (according to the manufacturer's definition), such as lights, switches, fuses.
Declaration of conformity
For the central condensing boiler units ROTEX GasSolarUnit
We, ROTEX Heating Systems GmbH, declare under our sole responsibility that the products
Product Order No. Product Order No.
ROTEX GSU 320 15 70 25 ROTEX GSU 320 F 15 70 26
ROTEX GSU 520S 15 71 10 ROTEX GSU 520S F 15 71 20
ROTEX GSU 530S 15 71 21 ROTEX GSU 530S F 15 71 23
ROTEX GSU 535 15 71 40 ROTEX GSU 535 F 15 71 45
with the product identification number CE 0085 BM 0065, together with one of the following regulations
Product Order No. Product Order No.
ROTEX THETA 23R (N) 15 40 52 ROTEX ALPHA 23R 15 40 54
ROTEX THETA 23R (S) 15 40 53
comply, in their standarddesign, with the following European Directives:
2004/108/EC Electromagnetic compatibility directive
90/396/EEC Gas appliances directive
2006/95/EC Low voltage directive
92/42/EEC Boiler efficiency requirements directive
Güglingen, 1.3.2007 Dr Eng. Franz Grammling
Managing Director

List of contents
3
BA ROTEX GSU - 09/2007
1 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 See the manual . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . 4
1.2 Warnings and explanation of symbols . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . 4
1.3 Danger prevention. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 5
1.4 Proper use. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 5
1.5 Instructions for operating safety. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 5
2 Product description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Design and components of boiler. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 7
2.2 Brief description . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 10
2.3 Gas burner . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. 11
2.4 Connections . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . 13
2.5 Storage tank. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 14
3 Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1 Safety. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 15
3.2 Instructions for erection . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Initial start-up. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 16
3.4 Instruction and handover to the owner . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 16
4 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 Operating elements on the boiler control panel. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.1 Control THETA 23R . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 17
4.1.2 Display and modification of parameters. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 19
4.1.3 Control ALPHA 23R . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 20
4.2 Heating mode . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 22
4.2.1 Manual setting of the boiler temperature. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 22
4.2.2 Pump setting for energy-saving operation . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.2.3 Information on operating noises . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . . 23
4.3 Temporary shutdown . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 24
4.4 Re-commissioning . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 24
4.4.1 Work to be done before re-commissioning . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . 24
4.4.2 Checklist for returning to service . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 26
5 Inspection and maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.1 General overview of inspection and maintenance. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 27
5.2 Inspection and maintenance tasks. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 27
5.2.1 Checking the connections and conduits.. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. 28
5.2.2 Checking and cleaning the condensatedrain.. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 28
5.2.3 Checking and cleaning the burner . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . 29
6 Faults and malfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 30
6.2 Malfunctions. . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . 30
6.3 Fault codes . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 32
6.4 Emergency operation. . . . . . .. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 35
7 Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.1 Dimensions and connection dimensions . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . 36
7.2 Wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 43
8 Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
9 For the chimney sweep. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

1 xSafety
4BA ROTEX GSU - 09/2007
1Safety
1.1 See the manual
This manual is meant for the owner of the ROTEX GasSolarUnit.
Theinstallation,connectionandtheinitialstart-up oftheROTEXGasSolarUnitarecarriedoutby authorisedand trainedheating
engineers. The ROTEX GSU was properly handed overto you by the installer. The handover is documented in the handing over
report.
Alltheactivitiesrequiredforoperation,forreturningtoserviceafteratemporaryshutdown aswellasafewbasicmaintenance
jobsaredescribedinthismanual.Activitiesforstartup,faultclearanceandmaintenance,whicharenotdescribedinthisinstruc-
tions manual, should be carried out only by authorised and trained heating engineers.
Please read carefully through this manual before operating the ROTEX GSU.
Relevant documents
– ROTEX GasSolarUnit: Installation and service manual for the heating expert.
The document is included in the scopeof delivery.
– The documentation of the used ROTEX Control. It is included in the scope of delivery of the Control.
1.2 Warnings and explanation of symbols
Meaning of the warnings
The warnings are classified in this manual according to their severity and probability of occurrence.
Special warning symbols
Some types of danger are represented by special symbols:
Validity
Some information in this manual has limited validity. The validity is highlighted by a symbol.
Order number
References to order numbers can be recognised from the goods symbol .
Handling instructions
• Handling instructions are shown as a list. Actions where the sequential order must be maintained are numbered.
ÎResults of actions are identified with an arrow.
DANGER!
Indicates imminent danger.
Disregarding this warning results in serious physical injury ordeath.
WARNING!
Indicates a potentially dangerous situation.
Disregarding this warning may result inserious physical injury or death.
CAUTION!
Indicates a possibly damaging situation.
Disregarding this warning may causedamage to property and the environment.
This symbol identifiesuser tips and particularly useful information, but not warningsor hazards.
Danger of explosion Electrical current Danger of burning or scalding
Valid only for ROTEX Control ALPHA 23R Valid only for ROTEX Control THETA 23R
aq

1 xSafety
5
BA ROTEX GSU - 09/2007
1.3 Danger prevention
ROTEX GasSolarUnit conforms to the state-of-the-art and meets all recognised technical requirements. However, improper use
may result in serious physical injuriesor death, as well as property damage.
The ROTEX GasSolarUnit must only be installed and operated as follows to avoid danger:
– As stipulated, and in perfect conditions,
– With an awareness of safety and dangers.
This assumes the knowledge and use of the contents of this manual and training in the operation of the ROTEX GSU by the
installer.
Danger of explosion if you smell gas
Escapinggasisadirectthreattohumanhealthandsafety.Evenafewsparkscancausemajorexplosions.Ifyousmellgas,please
follow these rules:
• Do not light an open flame and do not operate electrical switches.
• Open windows and ventilate the room well.
• Inform the authorised gas supply company.
1.4 Proper use
TheROTEXGasSolarUnitmayonlybeusedasahotwaterheatingsystem.TheROTEXGasSolarUnitmustbeinstalled,connected
and operated only according to the indications in this manual.
TheROTEXGasSolarUnitmayonly beusedwith acontrollerapprovedby ROTEX(seedeclarationofconformity inPage 2of this
instruction manual).
Any other use outside the above is considered as improper. The owner will be solely responsible for anyresulting damage.
Proper use also includes the adherence to the maintenance and inspectionconditions. Spare parts must at least satisfy the
technical requirementsdefined by the manufacturer. This is thecase, for example, with original spareparts.
1.5 Instructions for operating safety
Heating system
• Workon the heatingsystem(e.g. installation,connection andtheinitialstart up)mustbecarriedout only by authorisedand
trained heating engineers.
• Switchthemainswitchoffandsecureitagainstunintendedswitchingonwhencarryingoutanyworkontheheatingsystem.
• Set up the heating system as an open or closed heating system according to the safety-related requirements of EN 12828.
• Thesafetyvalves must conform to the DIN EN ISO 4126-1 and the components must be inspected. The safety valves must
be installed in the safety flow.
• The stickers on the gas condensing boilers must not be removed or damaged.
Electrical installation
• AllcontrolandsafetydevicesintheROTEXGasSolarUnitareconnectedreadyto operateand checked.Modificationsto the
electrical installation are dangerous and are prohibited. The owner will be solely responsible forany resulting damage.
• Workontheelectricalinstallationshouldonlybecarriedoutbyqualifiedelectricalengineersobservingthetechnicalelectrical
guidelines and regulations of the relevant electric power supply company.
Gas installation
• Work on the heatingand gas supply system shouldbe carried out only by authorised and trained technicalpersonnel.
• Work on gas burners must be carried out only by authorisedand trained technical personnel.
Air/flue gas system (LAS)
• The owner may not arbitrarilymodify the air/ flue gas system (LAS). Modifications tothe combustion air supply and the
exhaustconductionmaybecarriedoutonlybyauthorisedandtrainedtechnicalpersonnelafterapprovalbytheChiefDistrict
Chimney Sweep.

1 xSafety
6BA ROTEX GSU - 09/2007
Hydraulic system connection
• When operatingthe ROTEX GasSolarUnit,especially when usingthe solar energy,thestorage tank temperature can exceed
60 °C. Protection from scalding (hot water mixing device e.g. VTA32 15 60 16) should therefore be included when
installing the system.
Device installation room
• Operate ROTEX GasSolarUnit only if sufficient combustion air supply is ensured. If you operate the ROTEX GSU in ambient-
air-independent mode with an air/ flue gas system (LAS) dimensioned according to ROTEXstandard, this is guaranteed
automatically and there are no further conditions to be met in the device installation room.
• Makesurethatthereisanopeningtotheopenairforairinlet,ofatleast150cm2ifyouoperateintheambientairdependent
mode.
• Donotoperatetheburnerintheambientairdependentmodeinroomswithaggressivevapours(e.g.hairspray,perchloroeth-
ylene, carbon tetrachloride), heavydust formation (e.g. workshops) or high humidity (e.g. laundries).
• Always maintain the minimum distances from walls and other objects (seeChapter 7.1).
Operation
• Operate ROTEX GasSolarUnit only with the storage tank filled to overflow.
• Operate ROTEX GasSolarUnit only with closed silencer hoods.
Instruction by the installer
• ThehandoverincludesinstructionintheoperationandcontroloftheROTEXGasSolarUnitbytheinstaller,usingtheoperating
instructions.
• Document the handover by filling in and signing the attached installation and instructions form together with the installer.
Disposal
• Through the environmentally-friendly design of the ROTEX GasSolarUnit, ROTEX has complied with thestandards for
environmentally-friendly disposal.
• Properdisposalincompliancewiththerespectivenationalstipulationsofthecountryofuseistheresponsibilityoftheowner.
Documentation
• The technical documentation contained in the scope of supply is part of the device. It must be stored in such a way as to
ensure that the operator or technical personnel can always refer toit.

2 xProduct description
7
BA ROTEX GSU - 09/2007
2 Product description
2.1 Design and components of boiler
1Cold water1)
2Hot water1)
3Hot water charging heat exchanger inflow
4Hot water charging heat exchanger return flow
5Heating flow (warm)
6Heating return flow (cold)
7Solaris flow
8Solaris return flow with valve insert
9Flue gas
10 Air supply
11 Immersion sleeve for storage tank sensor and
Solaris return flow temperature sensor
12 Condensate overflow connection
12a Top filling connection (alternatively: condensate
overflow connection to the front
21 Heating circulation pump)
22 Gas fan burner
23 3-way diverting valve
24 Inflow temperature sensor
25 Return flow temperature sensor
27 Safety valve
28 Connection for diaphragm expansion tank
29 Boiler control panel
30 Control
31 Pressure gauge
32 Silencer hood
33 Retaining screws for silencer hood
34 Supply air hose
35 Filling and draining fitting (KFE cock)
36 Automatic aspirator
37 Shutoff ball valve
38 Thermal insulation tray for boiler body
39 Nameplate with manufacture number
Safety devices
1) Prepares for the installation of gravity brakes to
avoid cooling losses.
Figure 2-1 Components of the ROTEX GasSolarUnit

2 xProduct description
8BA ROTEX GSU - 09/2007
AGas condensing boiler
BHot water layered storage tank
CUnpressurised storage tank water
DHot water zone
ESolar zone
FHeating support zone
GRPS control and pump unit (Solaris accessories)
1Cold water1)
2Hot water1)
3Hot water charging heat exchanger flow
4Hot water charge changer return flow
5Heating flow (warm)
6Heating return flow (cold)
7Solaris flow
8Solaris return flow with valve insert
9Flue gas
10 Air supply
11 Immersion sleeve for storage tank sensor and
Solaris return flow temperature sensor
12 Condensate overflow connection
12a Top filling connection (alternatively: condensate
overflow connection to the front)
13 Condensate drain hose (by others)
14 Condensate pipe
15 Heating heat exchanger (boiler body)
16 Drinking water heat exchanger (TW-WT)
17 Heatexchangerforstoragetankcharging(SL-WT)
18 Heatexchangerforsolarheatingsupport(HU-WT)
19 Heat insulating jacket for HU-WT
20 Solaris flow layering pipe
21 Heating circulation pump
22 Gas fan burner
23 3-way diverting valve
24 Inflow temperature sensor
25 Return flow temperature sensor
26 Flue gas temperature sensor (accessory)
27 Safety valve
28 Connection for diaphragm expansion tank
Safety devices
1) Prepares for the installation of gravity brakes to
avoid cooling losses.
Figure 2-2 Schematic layout of GSU 520S and GSU 530S

2 xProduct description
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BA ROTEX GSU - 09/2007
AGas condensing boiler
BHot water layered storage tank
CUnpressurised storage tank water
DHot water zone
GRPS control and pump unit (Solaris accessories)
1Cold water1)
2Hot water1)
3Hot water charge changer flow
4Hot water charge changer return flow
5Heating flow (warm)
6Heating return flow (cold)
7Solaris flow
8Solaris return flow with valve insert
9Flue gas
10 Air supply
11 Immersion sleeve for storage tank sensor and
Solaris return flow temperature sensor
12 Condensate overflow connection
12a Top filling connection (alternatively: condensate
overflow connection to the front)
13 Condensate drain hose (by others)
14 Condensate pipe
15 Heating heat exchanger (boiler body)
16 Drinking water heat exchanger (TW-WT)
17 Heatexchangerforstoragetankcharging(SL-WT)
20 Solaris flow layering tube
21 Heating circulation pump
22 Gas fan burner
23 3-way diverting valve
24 Inflow temperature sensor
25 Return flowtemperature sensor
26 Flue gas temperature sensor (accessory)
27 Safety valve
28 Connection for diaphragm expansion tank
Safety devices
1) Prepares for the installation of gravity brakes to
avoid cooling losses.
Figure 2-3 Schematic construction of GSU 535 and of GSU 320

2 xProduct description
10 BA ROTEX GSU - 09/2007
2.2 Brief description
TheROTEXGasSolarUnitisacompletelypre-assembledgascondensationboiler,whichisintegratedinahotwaterstoragetank.
This integration ensures that thereare no external surface and cooling losses. The heat is given completely to the storagetank
water and not tothe surroundings. In addition, the excellent heat insulation of the plasticstorage tank ensures minimum heat
losses. The very flat cylinder-shaped aluminium boilerbody is recessed into the cover of the storagetank. The combustion
chamber is arrangedcentrally. The flue gas is directed in a spiral around the burner chamber and then taken away upwards.
The flue gas temperature always remains below 90 °C.
Solar utilisation
Thehot waterstoragetank ofROTEX GSUcan alsobe heatedbysolar energy.In themodels GSU 520S andGSU 530S, the gas
condensing boilersare designed to maintain only the upper zone of the storage tank at the target temperature. In solar heating,
the entire storage tank can be heated up, depending onthe heat offered by the sun. The stored heat is now used for hot water
generationaswellasfortheheatingsupport.Thehightotalstoragecapacityinthe500-litrestankevenallowstemporarytiding
over without sunshine.
In the models GSU 320 and GSU 535, the total storage tank is configured as zone fordomestic water. It is possible to make
thermal use of solar energy for hot water preparation. The solar component is optimisedin combination with an upstream
Solaris system (pre-heating stage).
Operating principle
TheROTEXGasSolarUnitis designedsuchthatitcanbeoperatedindependentlyoftheambientair. Thecombustionairis drawn
in through an installation shaft or a double-walled flue gas conduit from the burner directly from the open air. This method has
several advantages:
– The heating room needs no ventilation opening to the open air and therefore does not cool down.
– Lower energy consumption.
– Additional energy recovery in the flue gas line by combustion air pre-heating.
– Additionalenergyyieldfromadistinctivetemperaturelayeringsystem generatedinall devicesby thearrangementand flow
through the heat exchanger.
– Contaminationfromthe environmentaroundtheburnerisnot suckedin. Theheatingroom canthereforecanalsobe usedas
a work-room, laundry or for similar purposes.
– Possible to install as central roof unit and in garages.
Thedrinkingwaterisheatedindirectlyinastainlesssteelcorrugatedpipeheatexchangerbythepressurelessstoragetankwater
from the hot water tank. This contains about 24 litres(19 litres in GSU 320) of hot drinking water at the temperature level of
the domestic water zone. If ahigher quantity of hot water is tapped, thiswater is heated in the geyser principle.
The precipitating condensation is collectedat the lowest point ofthe boiler body, directed to the storage tank througha plastic
tube and neutralised there. From there, it is directed through the safety overflow connection.
Safety management
Theentire safetymanagementof the ROTEX GasSolarUnitis entrustedtoelectroniccontrol. Thiseffectsasafetyswitch-off in
theeventofwatershortage,gasshortageorundefinedoperatingstates.Acorrespondingfaultmessageshowstheexpertallthe
necessary information for troubleshooting.
Electronic control
A fully electronic digital control combinedwith the "intelligent" automatic firing unit of theburner controls all heating andhot
waterfunctionsfullyautomaticallyforthedirectheatingcircuit,anoptionallyavailablemixedheatingcircuitaswellasastorage
tank charging circuit. The continuously modulating control adjusts the heating output flexibly to the changing requirements.
All settings, displays and functions are made throughthe ROTEX Control THETA 23R or the ROTEX Control ALPHA 23R.
The display and the keyboard offer comfortable operations.
Adigitalroomstation(ROTEXTHETARS, 15 70 18)oraroomcontrollerset(THETA RFF, 15 40 70)areavailable
as option for greater convenience.
The room temperature control (ALPHA RTR-E, 17 51 26) is available asoption for more convenience.
Condensing technology
The condensing technology makes optimum use of the energy contained in the heating gas. The flue gas is cooled down in the
boilerandinthefluegassystem--intheambientair-independentmethod,suchthatthetemperatureisbelowthedewpoint.Part
of the water vapour generated on combustion of the gas thuscondenses. The condensation heat is addedto the heating, as
opposed to the case with low temperature boilers. This makesit possible to achieve efficiency levels higher than 100%.
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2.3 Gas burner
Figure 2-4 Gas burner of ROTEX GasSolarUnit - View from front
1Burner surface
2Fan
3Safety gas control block
4Gas/air compound controller
5Gas solenoid valve (1 x Class B and 1 x Class C)
6Automatic gas firing unit CVBC
7Gas connection G ½" female
8Venturi nozzle with air connection DN 50
9Measurement connection IN - inlet gas pressure
10 Measurement connection OUT - outlet gas pressure
11 Set screw for gas/air mixture
12 Set screw for gas pressure controller (under cover cap)
13 Burner flange
14/1 Ionisation electrode
14/2 Ionisation cable
15/1 Ignition electrodes
15/2 Ignition cable
16 Flue insert
17 Burner flange seal (O-ring)
18 Flue seal (flat graphite seal)
19 Fan flange seal (flat silicon seal)
20 Clamp plates Never unfasten!
21 Air intake pressure hose
22 Cover with strain relief for burner cable and locking screw for automatic gas
firing unit
Figure 2-5 Gas burner of ROTEX GSU - View from rear Figure 2-6 Gas burner of ROTEX GSU - Side view from left

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12 BA ROTEX GSU - 09/2007
Burner setting and power limiting
Thegasburnerisfactory-settoa gastype,whichis indicatedontheyellowstickeronthefan housingof theburner.Theburner
can be operated with the following gas types:
– Natural gas E/H
– Natural gas LL/L
– Liquefied petroleum gas.
Only the heating engineer can change the gas type because this requires resetting the gas burner.
The heating engineer can limit the burner output by entering parameters in the boiler control panel.
– The limiting of the maximum burner output would be advisable, for example,in the event of better supply charges for lower
installed outputs.
– The limiting of theminimum burner output would be advisable,for example, if the flue gas resistance is relatively high and
the flame becomes unstable on minimum load orif the requirements for the partial load are not fulfilled when making the
calculations for the flue gas system.
Controlling the burner output
The controls ROTEX ALPHA 23R and ROTEX THETA 23R determine the requisite flow temperature (corresponding to the set
operating parameters) continuously andfeed them to the CVBC automatic firingunits of the gas burner. The CVBC automatic
firing unit calculates the necessary burner output from the target value and the values of the flow and return flow temperature
sensors. The determined output is transmitted to the burner fan as a PWM signal. The burner fan immediately adjusts the fan
speed and thus alsothe combustion air flow. Thegas controller controls the gas volume accordingly.
Gas/air compound control
Thegas/aircompoundcontrol(pneumaticcompound)ensuresthattheCO2flowismaintained at asuitablelevelforeveryoutput
and is set by theadjusting screw for the gas/air mix (Fig 2-6, item 11) and bythe adjusting screw of the gas pressure controller
(Fig 2-6, item 12) if required. The burner immediately responds to every change in the air flow volume through the gas/air
compound control with a corresponding change in the gas flow volume.
Thegas/aircompoundcontrol(pneumatic compound)consistsof aVenturi nozzlewith aring-shapedgasinletanda gaspressure
controller.
A vacuum forms in the centre of the Venturi nozzle depending on the volume flow of the combustible air.This causes the gas to
be drawn into thecentre of the Venturi nozzle, conveyed through the burner fan to the burnersurface and optimally mixed.
The gas valve can be adjusted for supply pressures from 5 to 60 mbar (zero pressure controller).

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2.4 Connections
Temperature sensor
TheROTEXGSUhasaweather-drivencontroloftheflowtemperature.Thisfunctionrequiresanexternaltemperaturesensor.
A 3 m flexible cableis already connected insidethe device and placedin the control panel on the circuit board.
Thetemperaturesdetectedbytheinternaltemperaturesensorsofthedevice(flow andreturnflowtemperaturesensors)are
used for output control of the burner andthe detection of a fault.
The Storage tank temperature sensor is factory-assembled and connected (PTC resistance). The mixer circuit inflow
sensor (TMKF, 15 60 62) is required for the control of the mixer circuit .
Additional information about the operating status is provided by a flue gas temperature sensor (TAGF1 ,15 70 52).
Mixer circuit (optional)
A mixer circuit can be connectedto the ROTEX GSU directly, which is controlled through the electronic boiler control.
ROTEX offers the following:
– Theready-to-connectmixergroupAMK1( 15 60 44),whichcontainsacirculationpumpintegratedintheheatinsulated
housing, a motor mixer and check valves with temperature displays.
– The mixer circuit contact sensor TMKF ( 15 60 62).
Cascading (optional)
By cascading from the heat circuit expansion modules THETA HEM1 ( 15 60 61), the system can be expanded by
up to 5 mixer circuits and/or storage tank charging circuits. The required temperature sensors need to be ordered separately
(mixer circuit docking sensor TMKF ( 15 60 62), storage tank temperature sensor TSF( 156063).
Flue gas temperature sensor (optional)
You can install the flue gas sensor connection set TAGF1 ( 15 70 52) for an optimum operating control.
Room controller (optional)
You can connect a separate room controller THETA RFF ( 15 40 70) for each heating circuit remote setting of modes
and room temperatures from another room.
You can connect a separate room controller ALPHA RTR-E ( 17 51 26) for each heating circuit for remote setting of
modes and room temperature from another room.
Room station (optional)
All temperature values and modes of the control unit THETA 23R (central unit) can bedisplayed and changed through the
roomstation THETA RS ( 15 70 18). Apartfrom the chimneysweepand manualoperation function,alloperating elements
(display, keys, rotary knobs) and functions (e.g. switching time programs ) areidentical to those of the central unit.
The room station THETA RS can be installed ina suitable place in the building and can beused for the remote operation of the
boiler control.
Information about the dimensions and connecting dimensions is given in Chapter 7 "Technical data".
TheelectroniccontroldetectstheexistingsensorconfigurationautomaticallyonswitchingontheROTEXGSU.
You will find more instructions and anexact description in the documentation "ROTEX Control". It is included
in the scope of supply of the particular electronic control to be ordered separately.
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2.5 Storage tank
Important instructions for hydraulic integration
Observe the following instructions for hydraulicsystem integration of the ROTEX GasSolarUnit in order to avoid damage to
persons and property.
–Protection from scalding: When operatingthe ROTEX GasSolarUnit, especially when using the solar energy, the storage
tank temperature can exceed 60 °C. It is advisable therefore to take measuresthatpreventscalding (hot water mixing unit
such as VTA32 15 60 16) at the time of installation.
–Preventing flue gas escape:To preventflue gas from escaping,the storage tankmust be filledtooverflowwhen starting
up the ROTEX GasSolarUnit.
–Corrosionprotection:In someregions,supplycompaniesprovideaggressivedrinkingwater,whichbycancausecorrosion
eventostainlesssteel.Askyourwatercompanywhetheranycorrosionproblemsaredetectedwiththeuseofstainlesssteel
hot water storage tanks in their area. Suitable water preparation may be needed.
Design
– Dual shell fully plastic construction (corrosion-free).
– Space between internal and external tanks foam-filled with high heat insulation (low surface losses).
– Outer skin 3-4 mm thick (impact and shock proof).
Working method
The pressureless storage tank water is used aswater storage tank medium. Useful heat is fedin and out by completely
submerged, spiral stainless steel corrugated tubes (1.4404).
The hot water zone in the storage tank works as a combination of heat storage and geyser (seeFig 2-2 and Fig 2-3). The cold
waterflowingonremovalofhotwaterisfirstfeddowntothestoragetankintheheatexchangerandprovidesmaximymcooling
forthelower storagetank.Thehotwaterzoneis heatedup,ifnecessary,with thegascondensingboiler.Theflowthroughheat
exchanger for storage tank charging(SL-WT) is downwards from above. This raises the efficiency and the use of the solar unit.
Thedrinking watercontinuallyabsorbsthe heat fromthestoragetank water on itswayup. Thedirectionof throughflow bythe
countercurrent principle and the spiral shape of the heat exchanger creates a distinct temperature layering in the storage tank.
Ashigh temperaturescancontinueinthe topareaof the storagetank,it can achievea highhotwateroutput evenonlong draw-
off cycles.
– In the GSU 520S and GSU 530S models, the SL-WT ends about 40 cm above the tank floor. Only the hot water zone above
it is heated by the boiler. The tank volume below it is heated only if using solar energy.
– Inthe GSU320andGSU 535models,theSL-WTistakento the tankfloor. Theentirestoragevolume isheated bytheboiler
(greater hot water output readiness).
Water hygiene
Theseparation of pressurelessstoragetank waterandhot water flowing throughthecorrugatedtube heat exchangersensures
optimum water hygiene in ROTEX GSU:
– Zones with low flow or no flow donot exist on the hot water side.
– Deposition of sediment, rust or other precipitants, which can occurin large volume tanks, is notpossible.
– The water first stored is also removed first (First-in-first-out principle).
Storage tank water heating
Thestoragetankisfirstfilledwithpressurelessstoragetankwateratthetimeoftheinitialstart-up,andwhichisnotexchanged
at a later date.
The storage tank water can be heated by different methods:
– by the integrated gascondensing boiler,
– by an additional solar system (ROTEX Solaris system) connecteddirectly to the pressureless area,
– by an additional heat source connected directly to the pressureless area (e.g. hot water heat pump).
Maintenance
Calcium residues aredislodged as a result of thermaland pressure expansion and the high flow speeds in the heat exchangers
wash them away, scale deposits do not form. On the storage tank water side, the scale dissolved in thewater can precipitate
only once. Thesmooth surface of the stainlesssteel corrugated tube heat exchanger does not allow any calciumencrustations
(no deterioration of theheat transfer performance during theoperating period).
The filling level isonly checked at the annual boiler inspection and water is topped up if necessary.

3 xInitial start-up
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3Start-up
3.1 Safety
The following instructions are especially applicable for transport, erection, installation and initial start-up:
– LifttheROTEXGasSolarUnitonly by thehandlesprovidedfor the purpose. Lifting or shifting the ROTEX GSU bythe panels
can damage the device (see Chapter 3.2).
– The erection surface must be solid, even and horizontal. Install a pedestal if necessary (see Chapter 3.2).
– Observe requirements in relation to installation room (see Chapter 1.5).
– The country's firing ordinance in force and DIN18160 are valid for the execution and measuring of the flue gas system.
The properties of the flue gas system must be marked on the system (nameplate in the installation room).
– Thespecialisedcompanycarryingouttheworkmustcometoanagreementwiththedistrictchimneysweepbeforebeginning
the work. We recommend documenting the participation of the districtchimney sweeps in a form sheet.
– Theelectrical connectionshouldonlybeperformed by electrical engineers incompliancewithvalidstandardsandguidelines
as well as the specifications of the energy supply company.
– Only heating specialists trained and authorised bythe gas or energy supply companies should beallowed to work on gas
systems.
– Carry out gas connection conforming to the technical rules for gas installation as well as the relevant specifications of the
country of destination and the gas supply company.
3.2 Instructions for erection
Scope of delivery
– TheROTEXGSU(turnkeypre-assembled)consistingofsolarstoragetank,gascondensingboilerwithmodulatinggasburner,
theintegratedcirculationpump,3-wayswitchvalve,internaltemperaturesensorsinthedevice(inflow,returnflow, storage
tank, safety group and ball cock.
– The document folder with installation and maintenance instructions,operating manual, installation and training forms
– Optional: Flue gas temperature sensor.
.
Installation versions
The ROTEX GSU is designed basically forambient air independent operation. They are fitted with a concentric flue gas/air
supply connection DN 80/125. ROTEX recommends using the ROTEX GSU in ambient air independent operation. If possible,
choose this installation version!
In the conditionally ambient-air independentand ambient air -dependent operationmodes,the installationroom musthave
a ventilation opening of at least 150 cm2to open air. As such, the installation room will not beassigned the heated building
envelope under the Energy Conservation Ordinance (EnEV), which downgrades the energy rating of the building.
WARNING!
Animproperlyinstalledandoperatedgascondensingboilercanendangerhumanlifeandhealthanditsfunction
can be impaired.
• Installation and start-up of the gas condensing boiler should be carried out only by gas or energy supply
company authorised and trained heating engineers.
Incorrect start-up voids the manufacturer's guarantee for the device.
If you have questions,please contact your heating installer or our Technical Customer Support.
WARNING!
TheROTEXGSUistop-heavyintheemptyconditionandcantipoverduringtransport.Thiscouldputpersons
in danger or causedamage to the unit.
• Lift the ROTEX GSU carefully, use the handles.
The ROTEX GSU cannot function without central control unit. The control in the correct version must be
ordered and is delivered in a separate package.

3 xInitial start-up
16 BA ROTEX GSU - 09/2007
Dirt filter in the heating return flow and cold water inlet
If the ROTEX GasSolarUnit isconnected to a heating or cold water system, in which piping or radiators made of steel ornon-
diffusion-proof floor heating pipes are used, sediment and swarf can enter the boiler or thestainless steel corrugated tube heat
exchanger and cause blockage, local over-heating orcorrosion damage. ROTEX thereforerecommends the installation of a
contamination filter inthe heating return or cold water feed ( 15 60 11 for units up to 28 kW, 15 60 12 for units up
to 50 kW).
Surface temperature
– Inambientair-independentmode,atratedpower,thedesigndoesnotallowtemperatures>80°Conanycomponentlocated
outsidetheunitcladdingpanels.Therefore,no minimumdistanceis requiredto componentsmadefrom flammable materials.
– Aminimum distance of 50 mm betweentheflue gas duct and flammablecomponentsshould bemaintainedin a partial ambi-
ent air-independent and ambient air-dependent mode.
– Do not use easily flammable and easily combustible substancesdirectly next to the ROTEX GSU.
Installation in garages
The ROTEX GSU is entirely suitablefor installation and operation within a garage. Requirements:
– Ambient air-independent operation,
– A durable operating manual placed in a visible location near the boiler,
– Theconstructionmustincludeaprotectivedeviceagainstmechanicaldamage(vehicle!)fortheentiresystem(e.g.abracket
or deflector).
3.3 Initial start-up
The technical staff can commission the ROTEX GSU after complete erection and connection.
3.4 Instruction and handover to the owner
The ROTEX GasSolarUnit is handed over to you after the technical staff have commissioned it. The installer will instruct you in
the servicing and operation of the ROTEX GSU at the time of handing over.
The instructions contain at least the following topics:
– ExplanationofsecureandproperuseoftheROTEXGasSolarUnitaswellasthelegallyimposedobligations,whichareincum-
bent on you as the owner of a gas heating system,
– Explanation of the operating elements and the setting options which you can make,
– Explanation of the possible modes with reference to an economic and energy-saving operation,
– Explanation of thenecessary cleaning and maintenance jobs which you can carry out,
– Action on malfunctions.
WARNING!
Improperly started ROTEX GasSolarUnit can cause damage to human life and health andimpair its function.
• Only heatingengineers, authorised and trained bygas and energysupply companiesare allowed to start
up the ROTEX GSU.
Therequirementsand the tests beforestartup,startingup activitiesandthe necessary testsaredescribedin
detail in the installation and maintenance manual for expert operation.
The scope of delivery includes aninstallation and instruction form. Document proper handover by signingthe
form along with the installer.

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4Operation
4.1 Operating elements on the boiler control panel
4.1.1 Control THETA 23R
Mains switch
Switching the ROTEX GSU on and off When the heating system is on, the mains switch is illuminated in green.
Collective fault signal
During normal operation, the collectivefault signal is off. If it lights up, this indicates a malfunction.
Pressure gauge
– Black pointer: Indicationof the current water pressure in the heating system.
– Green range: Permitted water pressure range.
– Red pointer: Indication of the permitted minimum pressure.
The black pointer must be in the green range. If it is to the left of the red pointer, the water pressure must be raised by topping
up the system.
The ROTEX GasSolarUnit can be operated with the THETA 23R control or only with the ALPHA 23R control.
The electronic digital controls areto be used for controlling 2 heating circuits (direct heating circuit,mixer
circuit) and a storage tank charging circuit.
A more detailed description isgiven in the documentation of the "ROTEX Control". It is part of the scope of
supply of the electronic control to be ordered separately.
1Mains power switch
2Common fault indicator
3Not assigned
4Pressure gauge
5Control: Central unit THETA 23R
6Rotary button for selecting and setting functions
and parameters
7Selection of daytime room nominal temperature
8Selection of reduced room nominal temperature
9Selection of nominal temperature of hot water storage tank
10 Selecting the operating mode
11 Setting the automatic timer program
12 System information
13 Manual button for emission measurement, manual operation,
suppression function
14 Display
15 Compartment for quick reference operating manual
16 Retaining bolts for control system
Figure 4-1 Operating elements on the boiler control panel with integrated control THETA 23R
Malfunctioning is generally indicated by an error code on the display.
For troubleshooting information refer to Chapter 6 "Faults and malfunctions".

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Rotary switch
The rotary switch can be used for selecting operating settings, changing and storing target values.
Day target room temperature
Selection and setting of the target temperature in normal operation. Setting according to individual temperature sensitivity.
Reduced target room temperature
Selection and setting of the target temperature ineconomy operation (night reduction). Setting according to individual temper-
ature sensitivity.
Target temperature hot water storage tank
Selection and setting of the target hot water storage tank temperature Setting according to specific hot water requirement.
Selecting the mode
Setting the mode by tapping the mode selection key. The mode currently active flashes on the display. Selection and activation
of another mode with the rotary switch. A mark on the display above the respective symbol shows the mode currently selected.
* Thisfunction isnot available if a roomcontroller THETARFF is connected,or if theoperating modeof the controlhasbeen set to different settings for the
individual heating circuits.
Settingautomatic timer program
Selectionofoneofthe3pre-installedtimerprogramsP1,P2orP3.Youcanfindfurtherinstructionsandamoreexactdescription
in the documentation for "ROTEX control“. It is part of the scope of supply of the electronic control to be ordered separately.
System information
Calling up all system temperatures and operating statuses of the system components.
• Tap the system information key.
• Call up the desired information successively by using the rotary dial.
• Turn to the right (+): Increased regulation
• Turn to the left (–): Reduced regulation
• Tapping: Save the selected value
• Press and hold (3 sec): Enter the programming level (select level)
Itispossibletotriggeranunplannedstoragetankchargebyholdingthekeydownforalongtime(duringanecon-
omy phase).
HOLIDAY Frost-protected shutdown of heating andhot water (e.g. during holidays).
ABSENT Brief break in the heating mode during absence.
PARTY Extended heating operation over and above the heating period preset in AUTOMATIC MODE.
AUTOMATIC Automatic heating and economy mode according to timer program.
SUMMER Hot water mode according to timer program, heating switched offwith frost-protection. *
HEATING Continuous heating mode without time restriction.
REDUCED Continuous reduced heating mode without time restriction.
STAND-BY Frost-protected shutdown of heating and hot water.

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Emission measurement, manual operation, fault clearance function
You can call up 3functions by using the manualbutton.
– Functionsforemissionmeasurementforthe chimneysweep:Tapthemanualbutton. Firsttap:the burnerrunsat maximum
output, second tap: the burner runs at minimum output.
– Manualoperation:pressthemanualbutton for 5 sec.TheROTEX GSU is controlledaccording to thesettargetvalue (heat
generatortemperature).Thestoragetankchargesuntilthemaximumadjustablestoragetanktemperatureisreached.Itthen
switches over to heating.
– Faultclearance:Ifthedisplayshows"RESET",tapthemanualbutton.Ifaproblemrecurs,therootcausemustbeeliminated.
Display
All system temperaturesand operating conditions of the system components can be indicated on the display. In the event of a
fault, the relevant fault signal is issued.
Standarddisplayinnormaloperation:Currentdayoftheweek,currentdate,currenttime,heatgeneratortemperatureandactive
operating mode (marking bar).
4.1.2 Display and modification of parameters
Standard display
Modifying parameters
All parameters for the operation of theheater system can be displayed and set on theboiler control panel. You have no access
to some of the setting areas. They are protected by an access code and can only be called up by authorised technicians.
To modify a parameter, proceed as follows:
• Press the selector keys of the parameters to be set (e.g. for setting the Automatic timer program).
• Selectthe parametervalue by turningtherotary knob to theleftor to the right untilthe desiredvalue appearsinthe display.
• Accept the selection by pressing the rotary knob.
This manual will give you an overview of the method of parameter modification in the THETA 23R Control.
A detailed description is given in theoperating manual of the control.
Youseethecurrentoperatingparametersinthedisplayduringnormal
operation:
Day of the week, date, clock time, heat generator temperature
The marking bar identifies the active mode (the example shows the
Automatic timer program II)
Special displays:
– Ice crystal: System anti-freeze active
– Umbrella: Summer switch-off active
Figure 4-2 Standard display

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4.1.3 Control ALPHA 23R
Rotary switch I
The rotary switch (I) can be used to select the operating modes of the ALPHA 23R Control.
Only the operating and display elementsof the central units of the ROTEX Control ALPHA23R are described
below. Refer to Section 4.1.1 for theoperating elements of the complete boiler control panel.
1Mains power switch
2Common fault indicator
3Not assigned
4Pressure gauge
5Control: Central unit ALPHA 23R
6Rotary switch II
10 Rotary switch I – selection of operating mode
14 Display
15 Compartment for quick reference operating manual
16 Fastening catch for control
17 Button "+"
18 Button "–"
19 Suppression button
Figure 4-3 Operating elements on the boiler control panel with integrated control ALPHA 23R
STAND-BY Frost-protected shutdown of heating and hot water.
REDUCED Permanently reduced heating operation without time restrictions — reduced operation for hot
water.
HEATING Permanent heating operation without time restrictions — normal operation for hot water.
SUMMER Hot water operation, heating switched off with frost protection.
AUTOMATIC I Automatic heating and reduction mode accordingto the switching time program
"Professional" (individually adjustable).
AUTOMATIC II Automatic heating and economy mode according to switching time program "Family".
AUTOMATIC III Automatic heating and economy mode according to switching time program "Solar".