Trianco CLASSIC 6KW Owner's manual

Aztec System Boiler Installation Manual
1
6, 9, 11 & 12KW SYSTEM BOILER
INSTALLATION, OPERATION AND
SERVICING INSTRUCTIONS
Please read these instructions carefully before installing and operating this
appliance

Aztec System Boiler Installation Manual
2
Contents
1. Health & Safety
3
2. Pre-Installation Notes
3
2.1 Ventilation and Siting
3
2.2 Power Supply and Wiring
3
2.3 System
3
3. After Sales Service Information
3
3.1 How to Report a Fault
3
3.2 Technical Assistance
3
4. Introduction
4
5. Users Instructions
4-5
6. Simple Fault Finding
5
7. Technical Specification
5
8. Installation Instructions
6-7
8.1 Regulations
6
8.2 Health & Safety at Work Act
6
8.3 Siting the Boiler
6
8.4 Unpacking the Boiler
6
8.5 Fixing to the Wall
6
8.6 Ventilation Requirements
6
8.7 Water System
7
9. Sealed Water System Requirements
7-8
10. Wiring Instructions
9-14
11. Servicing Instructions
14
11.1 Parts Replacement
14-15
11.1.1 Casing Removal
14
11.1.2 PCB Assembly Replacement
14
11.1.3 High Limit Thermostat Replacement
14
11.1.4 Thermistor Replacement
14
11.1.5 Element Replacement
14
12. Fault Finding
15-19
13. Spares List
20
IMPORTANT:
General Information:
To keep your boiler running efficiently DO NOT OBSTRUCT OR COVER any ventilation air inlet on the appliance or the compartment where it is
installed.
To keep the casing clean, switch ‘OFF’ the boiler at the electrical supply and simply wipe with a damp cloth. DO NOT use abrasive cleaning fluids as
this may damage the stove enamel paintwork.
Important
The electrical supply requirements:-
The 2kW boilers and 6kW boilers meet the requirements of EN 61000-3.3.
The 9kW and 11kW boilers must be installed in premises having a service of ≥100A per phase.
The 12kW boiler must be installed in premises having a system impedance of not more than 0.1939 + 0.1939Ω.

Aztec System Boiler Installation Manual
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1. Health and Safety
Information for the User, Installer and Service Engineer
Under the Consumer Protection Act 1987 and the Health and Safety
at Work Act 1974, it is a requirement to provide information on
substances hazardous to health (COSHH Regulations 1998).
T R Engineering Ltd takes every reasonable care to ensure that its
products are designed and constructed to meet these safety
requirements when the products are properly installed and used. To
fulfil the requirements, products are comprehensively tested and
examined before despatch.
When working on the appliance, it is the responsibility of the user or
engineer to ensure that personal protective clothing or equipment
appropriate to parts that could be considered hazardous or harmful
is worn.
This appliance may contain some of the items below:
Insulation and Seals
Glass rope, mineral wool, insulation pads, ceramic fibre and glass
insulation.
When handling, avoid inhalation and contact with eyes. These may
be harmful and cause irritation to the skin, eyes, nose or throat. Use
disposable gloves, facemasks and eye protection.
After handling, wash hands and other exposed areas. When
disposing of materials, limit dust and the risk of inhalation by using
water spray. Ensure materials are securely wrapped.
Seek urgent medical attention if inhaled or ingested. Exposure to
eyes and skin should be followed by immediate cleansing of the
affected areas and medical attention if necessary.
Glues, Sealants and Paints
The glues, sealants and paints used present no known hazards when
the appliance is used in the manner of which it is intended.
Notes:
a) Electrical safety checks should be carried out by a competent
person.
b) It is a requirement of the guarantee and any extended warranty
that an annual service is carried out by a competent person.
Installation Engineers Signature
Company Name (if applicable)
Company Address
Company Tel. No
Please read these instructions fully before installing this appliance.
If in doubt seek expert advice.
These instructions should be kept in a place close to the appliance
for easy reference.
2. Pre-Installation Notes
Before installation, it is imperative that the following guidelines are
heeded to ensure the trouble-free and efficient operation of the
boiler.
2.1 Ventilation and Siting
When siting the boiler in a confined space it is essential that
adequate ventilation be provided. This will ensure that air is allowed
to circulate freely around the appliance keeping down the ambient
temperatures. Refer to Ventilation Requirements (Page 6) for
further details.
Ensure that the area surrounding the boiler is kept free of items
which would impede the good ventilation of the appliance (e.g.
towels, linen, etc.).
When siting the boiler, take into account the potential requirement
for future servicing. Enough space should be provided at the front of
the boiler to enable an engineer to adequately service and/or
replace items such as the PCB or heat exchanger. Space should also
be available for the removal of the front casing panel. Please refer to
Siting Information (Page 6) for clearance dimensions.
2.2 Power Supply and Wiring
The power supply to the premises must meet the minimum
requirements of the unit being installed, with special attention paid
to the supply current, cable size and RCD recommendation. The
supply voltage to the appliance must never drop below 207 volts.
When fitting external controls, such as a room thermostat or
programmer, particular consideration should be given to the wiring
of these secondary items into the appliance. Please refer to the
Wiring Instructions (Pages 9-14) for further details. Any breakdown
attended to by T R Engineering Ltd which is found to be caused by
incorrectly wired appliance will be chargeable.
2.3 System
Isolation valves must be fitted on both the flow and return pipe
work of each boiler to be installed. These are useful as from time to
time the boiler may require draining of water and the lengthy
drawing-off process can be avoided by the astute placement of
these valves. Please refer to Page 8 for further details.
Ensure that any isolation valves are open before first use and that
the system is full of water. The boiler can only be fitted in an upright
position.
3. After Sales Service Information
3.1 How to Report a Fault
A qualified field SERVICE ENGINEER is available to attend a
breakdown or manufacturing fault occurring whilst the appliance is
under guarantee.
The appliance must be made available for service during normal
working hours, Monday to Friday (no weekend work or bank
holidays accepted).
A charge will be made where:-
Our field service engineer finds no fault with the appliance
or,
The cause of breakdown is due to other parts of
plumbing/heating system or with equipment not supplied
by T R Engineering Ltd or,
Where the appliance falls outside the guarantee period
(see terms and conditions enclosed) or,
The appliance has not been correctly installed, as
recommended (see installation, operating and servicing
instructions).
NOTE: Over 50% of all service calls made are found to have no
appliance fault.

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3.2 Technical Assistance
Step 1: Always contact your installer in the first instance, which
must thoroughly check all his work PRIOR to requesting a service
visit from T R Engineering Ltd for assistance.
Step 2: If your appliance has developed an in-guarantee fault your
installer should contact T R Engineering Ltd for assistance.
What happens if my installer/engineer is unavailable?
Step 3: Contact T R Engineering Ltd. We will provide you with the
name and telephone number of our service agent. However, a
charge may apply if the fault is not covered by the appliance
guarantee (payment will be requested on site by our independent
service agent.
PLEASE NOTE: UNAUTHORISED INVOICES FOR ATTENDANCE AND
REPAIR WORK CARRIED OUT ON THIS APPLIANCE BY ANY THIRD
PARTY WILL NOT BE ACCEPTED BY T R ENGINEERING LTD.
Service Centre and Technical Support
Tel: [phone]
Fax: [phone]
Hours of Business
Monday to Thursday 8:30am –5pm
Friday 8:30am –2:30pm
4. Introduction
The Aztec electric system boiler is a wall mounted electric central
heating boiler designed with smaller properties in mind. Fitted
vertically only and requiring access to the front and the right hand
side of the boiler for servicing. Once the boiler is switched on it is
fully controlled by an automatic management system which
monitors the safety and running functions of the boiler. Designed to
work on a fully pumped wet system only. The boiler produces hot
water by passing water over electric heating elements housed in an
insulated copper heat exchanger.
There are four boilers in the range with outputs ranging from 6kW
(20.472 Btu/hr) to 12kW (41.000 Btu/hr).
Important Safety Notes
Read these instructions before installing your boiler.
The heating system must comply with the latest editions of British
Standards 5449 and The Building Regulations and Electrical Wiring
Regulations BS 7671.
1. Always switch OFF the electrical supply before removing
the cover.
2. If any part of the boiler is modified, then the
guarantee/warranty will be invalidated.
We recommend that you keep these instructions in a place near
your appliance for easy reference.
The Trianco Aztec system wall mounted boiler has been designed
to conform to European Directive/Standards EN60335-
1:1994/A16:2001, EN60335-2-35:1998/A1:2000, EN55014 –1:2000,
EN55014-2:1997, EN61000-3-2:2000 and EN61000-3-3:1995.
THE PERSON(s) WHO INSTALLS THIS APPLIANCE, SERVICES OR
CARRIES OUT ANY REMEDIAL WORK, I.E. ELECTRICAL FAULT
FINDING, MUST HAVE SUITABLE ENGINEERING QUALIFICATIONS.
WARNING: DO NOT SWITCH ON THIS APPLIANCE IF THERE IS ANY
POSSIBILITY THAT THE WATER MAY BE FROZEN.
THE INSTALLATION OF THIS APPLIANCE MUST MEET THE
REQUIREMENTS OF THE CURRENT ISSUE FOR ELECTRICAL
INSTALLATIONS, IEE WIRING REGULATIONS.
THIS APPLIANCE IS NOT INTENDED FOR USE BY PERSONS
(INCLUDING CHILDREN) WITH REDUCED PHYSICAL, SENSORY OR
MENTAL CAPABILITIES, OR LACK OF EXPERIENCE AND
KNOWLEDGE, UNLESS THEY HAVE BEEN GIVEN SUPERVISION OR
INSTRUCTION CONCERNING USE OF THE APPLIANCE BY A PERSON
RESPONSIBLE FOR THEIR SAFETY. CHILDREN SHOULD BE
SUPERVISED TO ENSURE THAT THEY DO NOT PLAY WITH THE
APPLIANCE.
5. User Instructions
The Trianco Aztec system boiler has been designed and constructed
to give years of trouble free service and these instructions are
provided to assist you in obtaining the best performance with the
least trouble and cost.
The boiler is fully automatic in operation and requires little attention
other than the setting of the thermostat and any external system
controls such as a room thermostat and time switch.
IMPORTANT
DO NOT COVER OR BOX IN YOUR BOILER, ALLOW AIR TO
CIRCULATE FREELY AROUND THE APPLIANCE.
WARNING: DO NOT ATTEMPT TO SWITCH ON THE BOILER IF THERE
IS ANY POSSIBILITY THAT THE WATER HEAT EXCHANGER IS
FROZEN.
Before firing the boiler, ensure the system is full of water and any
valves fitted on the system are open.
Check that the time switch/programmer (if fitted) is ON and the
room thermostat is calling for heat.
Set the boiler temperature to required temperature using the
control buttons.
Switch on the electrical supply to the boiler and after a few seconds
the boiler’s green and amber light should illuminate. Set the time
switch/programmer (f fitted) to the fitness and programs required.
The boiler will now operate automatically, cutting in and out
according to heat demand.
To Turn Off the Boiler
Switch off the boiler at the time switch/programmer (if fitted).
If the boiler is to be switched off for any length of time it is
recommended that the mains supply to the boiler is switched OFF.
Boiler Control Thermostat
The boiler control thermostat enables you to select the temperature
of the water leaving the boiler. It is calibrated between 35°C and
75°C.
Using a small screw driver set the temperature by turning the knob
to the required setting. The thermostat switches between low and
high (35°C and 75°C in 5°C increments).

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Boiler Indicator Lights
There are three LED indicator lights on the boiler fascia panel these
are:
LED 1- GREEN –Power on to the boiler.
LED 2 –AMBER –Illuminated –in run mode.
Flashing –temperature satisfied.
LED 3 –RED –Boiler fault.
LEDs 4-12 –RED –Temperature lights –35°C-75°C.
75°C
70°C
65°C
60°C
55°C
50°C
45°C
40°C
35°C
If the red LED light flashes, this means a fault has occurred. This
would result in the boiler continuing to operate at a reduced output.
If the red LED is permanently on, this indicates a fault has occurred
(see simple fault finding chart on Pages 15-19).
Room Thermostat
The room thermostat should not be positioned near a source of heat
such as a radiator or exposed to the sun as this will cause the central
heating to switch off before the room is up to temperature. Follow
the manufacturer’s instructions for best siting position for the
thermostat.
Frost Protection
If the boiler and central heating is shut down for many hours during
very cold weather, the water may be in danger of freezing. The
boiler incorporates a frost thermostat.
If the system is shut down for a long period during very cold
weather, it is advisable to completely drain the system. However,
frequent draining should be avoided, especially in hard water areas,
as this could lead to scaling of the boiler waterways.
WARNING: DO NOT SWITCH ON THIS APPLIANCE IF THERE IS ANY
POSSIBILITY THAT THE WATER HEAT EXCHANGER IS FROZEN.
Time Switch/Programmer
When choosing the operating times for your boiler, it is useful to
remember that central heating usually takes between half an hour
to an hour before it becomes effective.
It is suggested that the time switch/programmer is set to bring on
the heating about an hour after boiler shut down. The timer can
therefore be switched off earlier as an economy measure.
Cleaning Casings
Use hot soapy water applied with a damp cloth for the enamel, then
dry with a soft dry cloth.
Simple Maintenance
Ensure that the natural ventilation around the boiler is not
obstructed. If fitted in a compartment ensure all ventilation grilles
are clear.
6. Simple Fault Findings
If the boiler fails to start for no apparent reason make the following
checks before calling your service engineer.
Is the green LED illuminated?
NO
Check for blown fuse or blown circuit breaker. If replacement fuse
or circuit breaker fails again, call your service engineer.
If the red LED is permanently illuminated, contact your service
engineer.
Flashing red LED indicates an open circuit. The boiler can still be
operated. Your service engineer should be contacted.
Check to see if all external controls i.e. programmer or room
thermostat is calling for heat.
Resetting the Boiler
If a fault has occurred and the LED is illuminated but the pump
continues to run, then switching the power off for 30 seconds and
then on again should reset the light. This may be caused by the
ambient temperature around the boiler being too high. Check to
ensure that any boiler ventilation is not obstructed. If the fault
reoccurs, contact your engineer.
IMPORTANT: Electrical safety checks should be carried out by a
qualified electrical engineer.
7. Technical Specification
UNIT
Aztec
6kW
Aztec
9kW
Aztec
11kW
Aztec
12kW
Electrical Input
kW
6
9
11
12
Supply Current
amp
25
39
45
51
RCD Rating
amp
32
40
50
63
Minimum Cable Size
mm
4
6
10
16
Weight
kg
25
Water Content
litres
7
Width
mm
456
Depth
mm
289
Height
mm
705
Mains Supply
230V 50Hz
Max Operating Pressure
300kPa / 3 bar
Test Pressure
600kPa / 6 bar
Boiler Flow Temperature
Adjustable between 35°C and 75°C
Limit Thermostat
Factory set at 100°C
Casing Finish
Stove enamelled white
Thermal Insulation
Insulated with mineral fibre

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8. Installation instructions
8.1 Regulations
Installation of the boiler must comply with the following British
Standards and Regulations:
BS5449 –Forced circulation hot water central heating systems.
BS 7074 –Part 1: Code of practice for sealed water systems
The building regulations; Part ‘L’ (Northern Ireland)
Current I.E.E Regulations
Local water undertaking By-laws.
8.2 Health and safety at Work Act
The installer should be aware of his responsibilities under the act
and provide where necessary, appropriate protection for persons
carrying out the installation. In the interests of safety a competent
engineer should install the boiler and all wiring must be carried out
in accordance with current IEE regulations.
IMPORTANT
ALL ELECTRICAL WORK MUST BE CARRIED OUT BY A QUALIFIED
ELECTRICAL ENGINEER TO CURRENT IEE WIRING REGULATIONS.
8.3 Siting the Boiler
IMPORTANT: NOT TO BE INSTALLED IN A SHOWER COMPARTMENT
OR BATHROOM.
The boiler is designed to be fitted in an upright position only.
Ensure adequate clearance is allowed for making water connections
as the boiler can only be fully serviced from the front. The boiler
must also be fitted in a dry well ventilated position, which is not
subject to adverse temperature conditions (See Ventilation
Requirements).
Care should be taken when siting the appliance to make sure
adequate access is available for future servicing of the appliance.
Please note that the PCB and heat exchanger assembly may require
removal during such times.
When installed in a compartment with a hot cylinder (see Fig.1), we
recommend that the boiler is fitted in position 1, if fitted in position
2 provision should be made at the front of the boiler to enable the
removal of the front casing. In both cases, where any additional
equipment like a hot water cylinder or system controls are to be
fitted after the boiler has been installed, attention should be given
to ensure that they do not restrict access to the boiler for servicing.
8.4 Unpacking the Boiler
Carefully open the boiler carton, remove the boiler and place in a
safe place until required.
NOTE: ALWAYS STORE THE BOILER IN A DRY PLACE PRIOR TO
FITTING.
8.5 Fixing the Boiler to the Wall
The boiler should be fitted to a suitable wall in an upright position.
Using the fixing dimensions supplied work out position of the boiler,
mark three holes and fix wall mounting bracket and secure bottom
of the boiler to the wall.
8.6 Ventilation Requirements
If the appliance is to be fitted in a confined space or compartment
with a potential ambient temperature of 60°C or more, it is strongly
recommended that adequate ventilation is provided to prevent the
overheating of the boiler controls. Aeration of 110cm2will be
required to the compartment, in both high and low positions.
2
1
HOT WATER
CYLINDER
MIN
150
FRONT
MIN DISTANCE
150mm
FIG. 1
456mm
289mm
289mm
146
245
46
FLOW
RETURN

Aztec System Boiler Installation Manual
7
8.7 Water system
IMPORTANT: USE ONLY COMPRESSION FITTINGS WHEN
CONNECTNG THE BOILER TO THE CENTRAL HEATING SYSTEM.
The installation must comply with the requirements of the following
codes of practice:
BS 5449 Part 1: Forced Circulation Hot Water Systems
BS 7074 Part 1: Code of Practice for Sealed Water systems
BS 7593 Treatment of Water in Domestic Hot Water Central Heating
Systems.
The water system must be thoroughly flushed out with cold water
without the pump in position.
Refit the pump and fill the system. Vent all air from the system and
clear any air locks and examine the system for water leaks.
IMPORTANT: ENSURE ALL SERVICE VALVES ARE IN THE OPEN
POSITION.
Ensure boiler is fitted with flow pipe at top and return pipe at the
bottom.
The boiler is supplied with Ø22mm compression fittings both top
and bottom. The Aztec ranges of boiler are low water content
boilers so require a good flow rate at all times (see chart).
Model
Minimum Flow Rate/Min
6kW
8
9kW
10
11kW
11
12kW
12
Aztec boilers are approved for use on fully pumped open vented
systems and sealed systems. When fitting on a sealed system a 3 bar
safety valve must be fitted to the system. Where thermostatic
radiator valves are fitted it will be necessary to fit a bypass to obtain
minimum flow rates.
IMPORTANT: IF MINIMUM FLOW RATES ARE NOT OBTAINED THE
BOILER MAY GO TO LOCK OUT ON HIGH LIMIT THERMOSTAT.
Where more than 1 boiler is fitted refer to multiple boiler
instructions. System must be flushed out before adding inhibitor to
BS 7593:1992 Treatment of Water in Central Heating Boilers.
IMPORTANT: THIS BOILER IS TO BE FITTED ON FULLY PUMPED
SYSTEMS ONLY.
9. Sealed Water System Requirements
The installation must comply with the appropriate requirements of
the current issue of BS 4814, BS 5449, BS 6798 and BS 7074 Part 1
and 2.
Safety Valve
A 3 bar safety valve is fitted within the unit. The drain must be
routed to the outside of the building. The drain must not discharge
above an entrance or a window or any public access area, be clear of
any electrical fittings and positioned so that any discharge can be
seen.
Expansion Vessel Capacity
A diaphragm type expansion vessel, conforming to the current issue
of BS 4814. The expansion vessel must be connected to the system
at a point close to the inlet side of the circulating pump. The
expansion vessel volume depends on the total water system volume
and the initial system design pressure. For any system an accurate
calculation of vessel size is given in the current issue of BS 5449 and
BS 7074 Part 1.
The water content of the boiler is given in the technical
specification. Note: A higher initial design pressure requires a larger
volume expansion vessel.
The charge pressure must not be less than the static head of the
system, which is the highest point of the system above the
expansion vessel.
Capacity of Expansion Vessel
Where design information is not complete the following chart
(below) can be used for selecting the size of the vessel, it should be
noted that the size given in the table takes into account of fault
conditions.
NOTE: Failure to ensure the correct vessel size could result in
premature failure of the expansion vessel which in turn may
adversely affect other components in the system i.e. circulating
pump and diverter valve.
Safety valve setting (bar gauge)
3 bar
Vessel charge and initial system
pressure (bar gauge)
0.5
1.0
1.5
Total water content of system
Vessel Volume
Litre
Litre
Litre
Litre
25
2.3
3.3
5.9
50
4.4
6.7
11.8
75
7.0
10.0
17.7
100
9.4
13.4
23.7
125
11.7
16.7
29.6
150
14.1
20.1
35.5
175
16.4
23.4
41.4
200
18.8
26.8
47.4
FIG. 2
AZTEC
ELECTRIC
BOILER
110cm2
110cm2

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System Temperature
The normal running temperature of the system is 75°C, if a fault was
to occur then the safety device would allow the system temperature
to rise to 100°C. It is recommended that this figure be used in the
calculations of the vessel size.
Expansion vessel connection
The expansion vessel should be connected in the neutral part of the
system, this being the return pipe work close to the boiler. Refer to
sealed system pipe work layout drawing (Fig. 5).
Pressure Gauge
A 0 to 4 bar pressure gauge is fitted within the unit.
Inhibitor
If using an existing system take care to drain down the entire system
including the radiators then thoroughly clean out before fitting the
boiler. Attention is drawn to the current issue of BS 5449 and BS
7593 on the use of inhibitors in central heating systems.
Drain Tapping
A drain tapping is provided on the boiler. An additional tapping must
be provided at the lowest point of the system, which will allow the
entire system to be drained.
System Makeup
Water loss from the system should be replaced from a makeup
vessel connected to the system. This vessel should be higher than
the top of the system. Alternatively provision can be made by pre-
pressurisation of the system via a temporary hose connection and
through a double check valve (non-return) and stop valve.
There must be no permanent connection to the mains water valve
supply even through a non return valve.
Alternative Methods of Filling a Sealed System
METHOD A
HEATING
CIRCUIT
RETURN
STOP
VALVE
DOUBLE
CHECK
VALVE
ASSEMBLY
ANTI-VACUUM
VALVE
HOSE UNIONS
MAINS
WATER
SUPPLY
TEMPORARY
HOSE
TEST COCK
MAINS
WATER
SUPPLY
CISTERN &
OVERFLOW
PRESSURE PUMP &
REDUCING VALVE IF
REQUIRED
STOP
VALVE
HEATING
SYSTEM
(RETURN)
FIG. 3
PUMP FLOW CURVE
FIG. 4
Sealed System
Automatic
Air Vent
DHW
Cylinder
Central Heating
Flow
Return
Expansion
Vessel
Bypass
Valve
Drain Valve
Service
Valves
Pressure
Relief Drain
Off
3 Port
Valve
NOTE: Bypass must dissipate heat
and be min Dia. 22mm x 1.5 mtr
FIG. 5

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10. Wiring Instructions
All electrical work must be carried out in accordance with current
IEE wiring regulations (seventeenth edition).
Before commencing installation check power supply to the
property to ensure that there is sufficient current and voltage
available for size of boiler fitted. Take into account requirements
of other electrical appliances, the boiler must be connected to the
mains supply by means of a double pole isolator linked with 3mm
contact gap in both poles.
IMPORTANT:
After completing electrical installation work preliminary safety
checks should be carried out as described in BS 7671:2001.
The electrical supply requirements:
The 6kW boiler supply should meet the requirements of EN61000-
3.3.
The 9kW and 11kW boiler must be installed in premises having a
service supply ≥100A per phase and meet the requirements of IEC
60417-5855.
The 12kW boiler must be installed in premises having a system
impedance of not more than 0.1939Ω + 0.1939Ω.
A double pole RCD with a trip level sensitivity of 30mA can be used
capable of breaking full load current to BS EN 61008:1994.
NOTE: RCD unit can be used as the isolating switch if mounted close
enough to the boiler.
Miniature circuit breakers (MCB’s) MUST be fitted between RCD unit
and boiler and RCD and any external controls. Refer to technical
specification. For MCB rating refer to wiring diagrams.
It is important the correct size MCB is used in the supply from the
RCD to the boiler. An additional MCB rated 6A will be required to
supply the external controls.
Electrical Connections
WARNING: THIS APPLAINCE MUST BE EARTHED.
The mains connection block is located inside the boiler on a bracket
at the bottom left hand side of the boiler which can be directly
wired to the boiler MCB. Use the correctly rated cable.
Where the pump is wired directly back to the boiler both live and
neutral connections must be used with the earth being wired back
to the earth post.
IMPORTANT: CORRECT POLARITY MUST BE OBSERVED WHEN
BRINGING THE MAINS SUPPLY INTO THE BOILER.

Aztec System Boiler Installation Manual
10
PUMP
Blue
Grey
Orange
Red
Brown
Green/Yellow
Blue
Blue
Brown
Brown
Brown
Blue
Green/Yellow
Green/Yellow
Green/Yellow
Brown
Blue
Green/Yellow
RCD UNIT
MCB
3A
L E N
MCB
BOILER
N LE
EARTH
CONSUMER
UNIT
L L
PCB CONTROL
CALL L L E N
PUMP
Red
Green/Yellow
Brown
Blue
Blue
Brown
Orange
Orange
Red
Black
Brown
Red
Black
PROGRAMMER
L
N
CH
ON
HW
ON
CH
OFF
HW
OFF
Black
Red
ROOM THERMOSTAT
FROST THERMOSTAT TO BE CONNECTED TO TERMINALS 1 & 9 IF REQUIRED
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
WIRING DIAGRAM FOR HEATING ONLY SYSTEM CONTROL
FIG. 6

Aztec System Boiler Installation Manual
11
PUMP
Blue
Grey
Orange
Red
Brown
Green/Yellow
Blue
Blue
Brown
Brown
Brown
Blue
Green/Yellow
Green/Yellow
Green/Yellow
Brown
Blue
Green/Yellow
RCD UNIT
MCB
3A
L E N
MCB
BOILER
N LE
EARTH
CONSUMER
UNIT
L L
PCB CONTROL
CALL L L E N
PUMP
Red
Green/Yellow
Brown
Blue
Blue
Brown
Orange
Orange
Red
Black
Brown
Red
Black
PROGRAMMER
L
N
CH
ON
HW
ON
CH
OFF
HW
OFF
Black
Red
ROOM
THERMOSTAT
FROST THERMOSTAT TO BE CONNECTED TO TERMINALS 1 & 9 IF REQUIRED
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
CYLINDER
THERMOSTAT
N E L C SL N E L C SL
MOTORISED
VALVE
(HEATING)
MOTORISED
VALVE
(DHW)
Orange
Red
WIRING DIAGRAM FOR ‘S’ PLAN SYSTEM CONTROL
FIG. 7

Aztec System Boiler Installation Manual
12
PUMP
Blue
Grey
Orange
Red
Brown
Green/Yellow
Blue
Blue
Brown
Brown
Brown
Blue
Green/Yellow
Green/Yellow
Green/Yellow
Brown
Blue
Green/Yellow
RCD UNIT
MCB
3A
L E N
MCB
BOILER
N LE
EARTH
CONSUMER
UNIT
L L
PCB CONTROL
CALL L L E N
PUMP
Red
Green/Yellow
Brown
Blue
Blue
Brown
Orange
Orange
Red
Black
Brown
Red
Black
PROGRAMMER
L
N
CH
ON
HW
ON
CH
OFF
HW
OFF
Black
Red
ROOM
THERMOSTAT
FROST THERMOSTAT TO BE CONNECTED TO TERMINALS 1 & 9 IF REQUIRED
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
CYLINDER
THERMOSTAT
Orange
Red
WIRING DIAGRAM FOR ‘Y’ PLAN SYSTEM CONTROL
MID-POSITION
MOTORISED
VALVE
Black
FIG. 8

Aztec System Boiler Installation Manual
13
This link needs to be left connected on installation.
Fig 9
1 ELEMENT 2 ELEMENTS 3 ELEMENTS 4 ELEMENTS
JUMPER POSITIONS
FRONT OF BOARD
PUMP TERMINAL
BLOCK
L E N
GREEN/YELLOW
BLUE
RED
RED
RED
RED
RED
E
ELEMENT 1
ELEMENT 2
ELEMENT 3
ELEMENT 4
L1 L2 L3 L4
L E N
L E N
EARTH
ELEMENT 1
ELEMENT 2
ELEMENT 3
ELEMENT 4
BLUE
GREEN/YELLOW
RED
RED
HL STAT
L L
GREY
ORANGE
CALL BLOCK
SL L
L1
L2
L3
L4
THERMISTOR
HIGH LIMIT
THERMOSTAT

Aztec System Boiler Installation Manual
14
IMPORTANT: To prevent damage to the switch wires are left
disconnected. After installation connect the switch plug to the
connector on the printed circuit board as shown in the diagrams
below.
11. Servicing Instructions
To ensure reliable operation of your Aztec electric system boiler, it is
recommended that you have your boiler serviced once a year.
The person(s) who services or carries out any remedial work, i.e.
electrical fault finding must have suitable engineering
qualifications.
Isolate main supply before carrying out any service work.
Check all electrical connections on the PCB and electric elements to
ensure they are secure and clean.
Check insulation on wiring.
Ensure all air grilles are clean and free from obstructions.
Inspect seals around elements and also, the heat exchanger’s top
and bottom flanges.
11.1 Parts Replacement
11.1.1 Casing Removal
Isolate electrical supply to the boiler.
Remove 4 fixing screws securing front case in position.
Disconnect temperature button cables from the PCB.
This will allow the front casing to be removed.
IMPORTANT: All electrical connections should be checked. Loose
connections can cause problems.
The boiler is fitted with a manual reset high limit thermostat. Before
replacing any part, ensure that the thermostat does not require
resetting.
11.1.2 PCB Assembly Replacement
Ensure electrical supply to the boiler is isolated.
Remove the 4 fixing screws and washers (2 top and 2 bottom)
securing the front casing. Disconnect the temperature button cables
from the PCB and remove the front casing.
Disconnect the pump and call plug, the thermistor plug, the fan
(where fitted) and high limit thermostat plug.
Disconnect all element cables apart from the rear element.
N.B. Take note of wiring arrangement before disconnecting.
Now remove the grey pipe insulation, it is now possible to
disconnect the remaining element.
Will all elements disconnected, again taking note of wiring
arrangement, carefully disconnect and remove the element cables
from the PCB. IMPORTANT: Care must be taken.
Disconnect the remaining red and black power cables from the PCB.
For ease of access disconnect from the main terminal block both the
red and black cables and also the power input cables, leaving the
earth cable connected.
Free both the pump and call terminal blocks be removing the
terminal block fixing screws.
Finally remove the 4 fixing screws holding the PCB mounting bracket
in position and remove the PCB from the unit.
Re-fit in reverse order on reassembly always refer to wiring diagram.
11.1.3 High Limit Thermostat Replacement
Ensure electrical supply is isolated to boiler.
The high limit thermostat can be found fixed to top front face of the
boiler.
Remove 2 terminal connectors from high limit thermostat.
Remove 4 M6 nuts, clamping and then remove thermostat out from
behind.
It is important when replacing thermostat a heat sink compound is
used between back of thermostat and face of boiler. (See Fig. 10 for
positioning), and thermistor is clamped behind plate.
Inspect retaining straps and replace where necessary.
11.1.4 Thermistor Replacement
Isolate electrical supply to the boiler.
The thermistor is located fixed to the top side of the boiler above
the high limit thermostat.
Disconnect from PCB board and slide out from behind clamping
plate.
It is important when replacing thermistor ensure a heat-sink
compound is used between thermistor and boiler body (See Fig. 10
for positioning).
Inspect retaining strap and replace where necessary.
When replacing front casing, ensure the thermostat control shaft
passes through hole in front control panel.
11.1.5 Element Replacement
Isolate electrical supply to the boiler.
Drain down system.
Disconnect terminal connectors from high limit thermostat.
Remove thermistor from behind retaining strap.
Disconnect electrical elements and earth wire.
HIGH LIMIT
STAT
CLAMP
PLATE
THERMISTOR
Fig 10

Aztec System Boiler Installation Manual
15
Disconnect compression fitting top & bottom of the boiler.
Remove securing bracket on bottom of the boiler then carefully
remove top bracket.
Boiler unit can now be carefully removed.
Remove 8 fixing screws on top flange and withdraw the element
assembly.
Remove the bottom element positioning bracket.
Remove damaged element.
Refit in reverse order and ensure element seals are fitted.
Check for continuity through 2 terminals on each element.
IMPORTANT: Inspect all seals and changer where necessary.
11.2 Fault Finding
Red LED permanently illuminated indicates one of the following
faults.
High limit thermostat has operated or faulty electrical connections
The high limit thermostat is fitted to the front top of the copper
heat exchanger and secured in position with 2 retaining clamps.
Check electrical connections on thermostat and PCB to check
thermostat has not failed using a multi-meter check continuity
across terminals of the thermostat. To reset press red button in
centre of thermostat. Thermostat may have tripped due to one of
the following:
a) Faulty circulation pump
b) Isolation valve on system closed
c) Air trapped in system
d) Out of calibration limit thermostat
e) Temperature settings on PCB incorrect
f) No water in system
Thermistor
The thermistor is fitted to the front top of the heat exchanger and
secured in position with a clamp; the other end terminates with a
white connector that plugs on to the PCB. Check the connections on
the board to make sure it is correctly fitted; also inspect the
thermistor for any broken wires.
Mains Inlet Wiring
If the mains supply to the boiler is wired incorrectly on the inlet
terminal block. Check polarity.
PCB Damage
Inspect the LED lights and the boiler temperature control adjuster
for any damage to connections to the PCB controller.
Voltage Drop
If the voltage drops below 207 volts.
Red LED flashes indicates one of the following faults
Poor Electrical Connection
Check the electrical connections to the elements and the PCB
controller, a poor controller would show up as a fault.
Element Failure
To check elements for failure, disconnect each individual element
and check continuity through the element if there is continuity
between the two terminals the element is ok. Check each element
individually replacing the electrical connectors after testing.
Element Cables
If there is a break in the element cable, this would show up as a
fault. Check all element cables and connections.
Green LED
If the green LED is illuminated but the boiler is not functioning,
check that any external controls fitted are calling for heat. If no
external controls fitted check that link wire is in place on call
terminal block (refer to wiring diagrams).
Blown Fuse on PCB
If there is power to the boiler but no LED illuminated then the fuse
on the PCB may have blown. The fuse is located above the PCB
transformer (fuse type 20mm 630mA anti-surge Bessman Type
S560). The fuse may have blown due to one of the following:
a) When multiple boilers are fitted and a larger pump is used.
If the pump is wired directly into the PCB the fuse may
need upgrading.
b) If the call terminal is used to supply power to ancillary
controls.
RCD Unit Trips
Check that the RCD unit is correctly rated for boiler size. If under-
sized change. Inspect mains terminal block wiring for short-
circuiting. Check electrical elements for earth continuity, if element
is found to be faulty fit new element.
Thermistor Values
Temperature (°C)
Resistance (Ohms)
0
32554
5
25339
10
19872.2
15
15698.5
20
12487.7
25
10000
30
8059.1
35
6543.7
40
5329.9
45
4371.7
50
3605.3
55
2988.7
60
2490
65
2084.4
70
1753
75
1480.9

Aztec System Boiler Installation Manual
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NO HEAT –PERMANENT GREEN LIGHT
IS THE
PROGRAMMER
TURNED ON I.E.
CALL SIGNAL?
NO
YES
CHECK
ELECTRIC
SYSTEM
CIRCUIT
IS CALL WIRE LIVE I.E.
LINE VOLTAGE?
CHECK
EXTERNAL
CONTROLS ARE
CALLING FOR
HEAT
NO
YES
IS THE HEAT EXCHANGER
GETTING UP TO
TEMPERATURE –AMBER
ON OR FLASHING
YES
NO
CHANGE PCB
ARE ISOLATING
VALVES OPEN?
NO
OPEN
ISOLATING
VALVES
IS THE PUMP
RUNNING?
YES
CHECK SYSTEM
PRESSURE & PIPE
WORK FOR AIR
LOCKS
NO
YES
CHECK LIVE &
NEUTRAL TO PUMP
LIVE & NEUTRAL
OK?
CHANGE PUMP

Aztec System Boiler Installation Manual
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FLASHING RED LIGHT
REPLACE
CABLES
ARE CABLES AND
CONNECTIONS
OK?
NO
YES
IS THERE POWER
TO ALL
ELEMENTS?
YES
IS THERE
CONTINUITY
ACROSS THE
ELEMENTS?
YES
DOES THE PUMP
GIVE CORRECT
FLOW?
YES
CHANGE PCB
REPLACE ELEMENT
OR HEAT
EXCHANGER
NO
ARE JUMPERS SET
CORRECTLY?
YES
CHANGE PCB
NO

Aztec System Boiler Installation Manual
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PERMANENT RED LIGHT
IS INCOMING POWER
SUPPLY OK?
YES
CHANGE PCB
YES
DOES THE BOILER GO
FROM GREEN TO
AMBER TO RED?
NO
DOES THE BOILER
GO STRAIGHT TO
RED LIGHT?
YES
HAS THE HIGH LIMIT
STAT TRIPPED?
YES
NO
REPLACE
THERMISTOR
CABLE
REPLACE FAULTY
CABLES OR
CONNECTIONS
CHANGE PCB
REFILL TO 1 BAR
& CHECK FOR
LEAKS
RE-SET HIGH
LIMIT STAT
IS THE SYSTEM
PRESSURE
SUFFICIENTLY
CHARGED?
YES
ARE THE LIMIT
STAT
CONNECTIONS
OK?
IS THE THERMISTOR
CABLE FAULTY?
NO
NO
YES
NO

Aztec System Boiler Installation Manual
19
NO GREEN LIGHT
IS INCOMING POWER
SUPPLY OK?
HAS THE RCD
TRIPPED?
HAS THE FUSE
BLOWN ON THE
PCB?
NO
YES
CHANGE FUSE
AND CHECK
PUMP
YES
NO
NO
RESET RCD
CHANGE PCB
NO
IS THERE
POWER TO LIVE
& NEUTRAL?
CHECK SYSTEM
WIRING

Aztec System Boiler Installation Manual
20
ITEM
PART No.
DESCRIPTION
QUANTITY
1
211501
ELEMENT FLANGE W.U.
1
2
211503
HEATER BODY W.U.
1
3
211701
3KW ELEMENT
4
4
211509
GASKET
1
5
211554
INSULATION FRONT & SIDES
1
6
211555
INSULATION REAR & BASE
1
7
207296
AUTOMATIC AIR VENT
1
8
211549
AIR VENT FITTING
1
9
99592
DRAIN COCK
1
10
91088
M6 X 16 HEX HD SETSCREW
12
11
92199
M6 SHAKEPROOF WASHER
12
12
94217
M6 HEX NUT
12
10
6
11
5
4
3
7
1
12
2
9
8