Trianco CLASSIC 2KW User guide

Aztec Classic Electric Boilers
1
CLASSIC 2, 6, 9, 11 & 12KW BOILER
INSTALLATION, OPERATION AND SERVICING
INSTRUCTIONS
Please read these instructions carefully before installing and operating this
appliance

Aztec Classic Electric Boilers
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
3-4
3.1 How to Report a Fault
3
3.2 Technical Assistance
4
4. Introduction
4
5. Users Instructions
5
6. Simple Fault Finding
6
7. Technical Specification
6-9
8. Installation Instructions
6
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
7
8.7 Water Systems
7-9
9. Multiple Boiler Installations
9-10
10. Wiring Instructions
11
11. Servicing Instructions
17
11.1 Parts Replacement
17
11.2 Casing Removal
17
11.3 PCB Assembly Replacement
17
11.4 High Limit Thermostat Replacement
17
11.5 Thermistor Replacement
17
11.6 Element Replacement
18
12. Fault Finding
18
13. Spares List
23-24
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 Classic Electric Boilers
3
1. Health & Safety
Information for the Installer and Service Engineers
Under the Consumer Protection Act 1987 and the Health & Safety at
Work Act 1974, it is a requirement to provide information on
substances hazardous to health (COSHH Regulations 1988).
The company takes every reasonable care to ensure that these
products are designed and constructed to meet these general safety
requirements, when properly used and installed.
To fulfil this requirement products are comprehensively tested and
examined before despatch.
When working on the appliance it is the Users/Engineers
responsibility to ensure that any necessary personal protective
clothing or equipment is worn appropriate to parts that could be
considered as being hazardous to health and safety.
This appliance may contain some of the items below:
INSULATION AND SEALS
Mineral fibre, insulation.
May be harmful if inhaled. May be irritating to the skin, eyes, nose
or throat. When handling avoid inhalation and contact with eyes.
Use (disposable) gloves, face masks and eye protection.
After handling wash hands and other exposed parts. When
disposing, reduce dust with water spray, ensure parts are securely
wrapped.
GLUES, SEALANTS & PAINT
Glues, sealants and paints are used in the product and present no
known hazards when used in the manner for which they are
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.
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 7) 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 boiler 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 11) for full details. Any breakdown
attended to by T R Engineering Ltd which is found to be caused by
an incorrectly wired appliance will be chargeable.
It is important that the pump is wired back to the boiler as shown in
the wiring diagram.
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 be fitted only in an upright position, with the flow
connection to the top of the boiler.
3. After Sales Service Information
A qualified field service engineer is available to attend a breakdown
occurring during the boiler’s guarantee period.
The boiler must be made for attendance during normal working
hours, Monday to Friday.
3.1 How to Report a Fault
Step 1
Contact your installation or service engineer, who should assess the
unit and works carried out on the appliance prior to requesting the
attendance of an engineer from T R Engineering Ltd.
Step 2
Please note that upon attendance by a T R Engineering Ltd
engineer, a charge will be made where:
-The engineer finds no fault with the boiler.
-The cause of the breakdown is due to parts of the system not
manufactured or supplied T R Engineering Ltd.

Aztec Classic Electric Boilers
4
-The boiler has not been installed in accordance with these
instructions.
-The boiler has not been commissioned by a qualified engineer.
-The boiler has not been serviced annually since installation.
-The breakdown occurs outside the guarantee period.
-The appliance has not been maintained correctly.
-The breakdown occurs dues to use of the boiler not sanctioned
by these instructions.
-The breakdown occurs as a result of work on the appliance by
an unauthorised third-party.
Important:
Invoices for attendance and repair work by any third-party will not
be accepted unless authorised in advance by T R Engineering Ltd.
3.2 Technical Assistance
A team of trained technical advisors are available to discuss any
problem with the appliance. In many cases, the problem may be
solved over the telephone, eliminating the need for an engineer’s
visit.
Before making contact, please have the following information ready:
-The appliance serial number or your unique customer
identification number (issued upon registration of the
appliance with T R Engineering Ltd).
-A description of the fault and any unusual behaviour by the
boiler before the failure occurred.
-The installation and commissioning dates and the details of any
annual services.
Appliance Serial No:___________________
Cust. ID No:__________________________
Installation Date:___/___/___
Service Centre and Technical Support
Tel: [phone] Fax: [phone]
Hours of Business
Monday-Thursday 8:30am –17:30pm
Friday: 8:30am –14:30pm
4. Introduction
The Aztec electric 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
stainless steel heat exchanger.
There are five boilers in the range with outputs ranging from 2kW
(6825 Btu/hr) to 12 kW (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 wall mounted boiler has been designed to
conform to European Directive/Standards.
EN 60335-1:1994/A16:2001, EN 60335-2-35:1998/A1:2000, EN
55014-1:2000, EN 55014-2:1997, EN 61000-3-2:2000 and EN 61000-
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 HEAT EXCHANGER IS FROZEN.
THE INSTALLATION OF THIS APPLIANCE MUST MEET THE
REQUIREMENTS OF THE CURRENT ISSUES FOR ELECTRICAL
INSTALLATIONS IEE WIRING REGULATIONS.
5. User Instructions
The Trianco Aztec 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 to the system are open.
Check that the time switch/programmer (if fitted) is ON and the
room thermostat is calling for heat.
Switch on the electrical supply to the boiler and after a few
seconds the boiler’s green and amber light should illuminate.
Set the boiler thermostat to the required temperature using
the control buttons.

Aztec Classic Electric Boilers
5
Set the time switch/programmer (if fitted) to the times and
programs required.
The boiler will now operate automatically, cutting in and out
according to the 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 screwdriver set the temperature by turning the knob
to the required setting or when the case is fitted use the buttons to
switch between low and high (35°C and 75°C in 5 degree
increments).
Boiler Indicator Lights
There are twelve LED indicator lights on the boiler fascia panel these
are:
LED 1 –GREEN –Power to the boiler
LED 2 –AMBER –Illuminated –In run mode
Flashing –Temperature satisfied
LED 3 –RED –Boiler fault
LED 4-12 –RED –Temperature lights 35°C –75°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 Page 5).
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
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 i 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.
Boiler Pump Overrun
The pump will overrun for a short period of time after the boiler
turns off.
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 shutdown. The timer can therefore be switched off
earlier as an economy measure.
Cleaning Casings
Use hot soapy water applied with a damp dry 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 Finding
If the boiler fails to start for no apparent reason make the following
checks before calling your service engineer.
1. Is the green LED illuminated?
NO
2. If the red LED is permanently illuminated contact your
service engineer.
3. Flashing red LED indicates an open circuit. The boiler can
still be operated. Service engineer should be contacted.
4. 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 red 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.

Aztec Classic Electric Boilers
6
7. Technical Specification
MODEL
Aztec
2kW
Aztec
6kW
Aztec
9kW
Aztec
11kW
Aztec
12kW
Electrical Input
2kW
6kW
9kW
11kW
12kW
Supply Current (amp)
8.5A
25A
39A
45A
51A
RCD Rating (amp)
13A
32A
40A
50A
63A
Minimum Cable Size (mm)
1
4
6
10
16
Weight (kg)
7.0
8.1
10.6
10.8
10.8
Water Content (litres)
1.0
2.1
3.2
3.2
3.2
Width (mm)
164
164
164
164
164
Depth (mm)
130
130
130
130
130
Height (mm)
550
823
1073
1073
1073
Mains Supply
230V 50Hz
Max Operating Pressure
3 bar
43.5 psi
Test Pressure
6 bar
87 psi
Boiler Flow Temperature
Adjustable between 35°C and 75°C,
located on the front casing
Limit Thermostat
Factory set at 100°C
Casing Finish
Stove enamelled white
8. Installation Instructions
8.1 Regulations
Installation of the boiler must comply with the following British
Standards and Regulations:
BS 5449 –Forced Circulation Hot Water Central Heating Systems.
BS 7074 –Part 1 –Code of Practice for Sealed Water Systems.
The Building Regulations
Current I.E.E Regulations
Local water undertaking By-Laws
8.2 Health & 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 wiring 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 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 not the PCB and heat exchanger assembly may require
removal during such times.
When installed in a compartment with a hot water 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 give to ensure that they do not restrict access to the boiler for
servicing.
8.4 Unpacking the Boiler
Carefully open the boiler carton, remove boiler and place in a safe
place until required.
NOTE –ALWAYS STORE THE BOILER IN A DRY PLACE PRIOR TO
FITTING. DO NOT ALLOW THE BOILER TO BE STORED WITH THE
CASING REMOVED.
8.5 Fixing Boiler to the Wall
Important:
DO NOT CUT FLOW AND RETURN PIPES
1. The boiler should be fitted to a suitable wall in an upright
position. Flow tapping must be at the top of the boiler.
2. Using fixing dimensions supplied work out position of boiler,
mark four mounting holes and drill 6mm diameter to a depth of
38mm.
3. Fit plastic wall plugs into holes and fit bottom two mounting
screws.
4. Hang on bottom two screws and push the boiler back towards
the wall and secure in position with top two fixing screws. The
flow tapping must be at top of the boiler (continued on Page 7).
MIN DISTANCE
150MM
MIN
150
1
2
Hot Water
Cylinder
FIG. 1
FLOW
TOP BRACKET
TOP CASING CAP
FRONT VIEW
SIDE VIEW
FIG 2
FIG. 2

Aztec Classic Electric Boilers
7
2kW
6kW
9-12kW
A
566
839
1089
B
586
859
1109
C
550
823
1073
D
107
107
107
E
164
164
164
MINIMUM CLEARANCES:
FRONT –150mm
From other fixed equipment:
TOP –100mm
BOTTOM –100mm
L/H SIDE –50mm
R/H SIDE –100mm
NOTE: APPROXIMATELY 750mm WILL
BE REQUIRED AT THE FRONT OF THE
APPLIANCE TO ENSURE ADEQUATE
ACCESS BY AN ENGINEER DURING
ROUTINE SERVICING.
5. Removing four casing screws and washers will allow casing to
be removed.
6. Slide top casing cap upwards this will allow front casing to slide
forward.
7. With the front casing removed fit three strain relief bushes into
base of back panel.
8. Fit pipe sealing grommet into top casing panel and cut off end
to allow pipe to slide through (See Fig. 4).
IMPORTANT: TOP CASING PANEL WITH GROMMET MUST BE RE-
FITTED BACK IN POSITION BEFORE MAKING TOP PIPE
CONNECTION. ALTERATION OR FAILURE TO COMPLY WILL
INVALIDATE THE WARRANTY.
9. When re-fitting casings slide front casing back into position
ensure small temperature adjuster on PCB passes through the
hole on the control panel. Slide the top-casing panel down into
position and secure panels into position using the four screws.
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 above, it is strongly
recommended that adequate ventilation is provided to prevent the
overheating of the boiler controls. Aeration of 100cm2will be
required to the compartment, in both high and low level positions.
8.7 Water Systems
IMPORTANT: USE ONLY COMPRESSION FITTINGS WHEN
CONNECTING THE BOILER TO THE CONTRAL 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.
D
E
A
B
C
FIG 3
FIG. 4
Flow Pipe
Pipe Seal
Top Casing
Fitting pipe Seal
Fitting Strain
Relief Bushes
Strain Relief
Bushes
FIG. 5
100cm2
100cm2
Aztec
Electric
Boiler
FIG. 6

Aztec Classic Electric Boilers
8
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. Clear any air locks and examine the
system for water leaks.
IMPORTANT: ENSURE ALL SERVICE VALVES ARE IN OPEN POSITION.
Ensure boiler is fitted with flow pipe at the top and return pipe at
the bottom.
The boiler is supplied with 22mm tail pipes top and bottom for
connection to the system.
The boiler must be installed using 22mm compression fittings both
top and bottom.
The AZTEC ranges of boilers are low water content boilers so require
a good flow rate at all times (see below chart).
Model
Min Flow Rate/Min
Aztec 2kW
4 Litres
Aztec 6kW
8 Litres
Aztec 9kW
10 Litres
Aztec 11kW
11 Litres
Aztec 12kW
12 Litres
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 MIN 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
installations.
System must be flushed out before adding inhibitor to BS 7593:1992
Treatment of Water in Central Heating Boiler.
IMPORTANT: THIS BOILER IS TO BE FITTED ON FULLY PUMPED
SYSTEMS ONLY.
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.
THE INSTALLATION ENGINEER MUST BE REGISTERED AS A
COMPETENT UDHWSS INSTALLER.
Safety Valve
A safety valve set at 3 bar must be fitted with the drain 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.
Expansions Vessel Capacity
A diaphragm type expansion vessel, conforming to the current issue
of BS 4814. The expansion vessel must be connected to the systems
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 that is the highest point of the system above the expansion
vessel.
Capacity of Expansion Vessel
Where design information is not complete the following chart (Page
9) can be used for selecting the size of the vessel, it should be noted
that the size given in the table account of fault conditions.
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 vessel size.
Connection of the Expansion Vessel
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 11).
Pressure Gauge
A pressure gauge must be permanently fitted in the system covering
a range from 0 to 4 bar. Position where it can be seen when filling
the system.
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 must be provided at the lowest point of the system,
which will allow the entire system to be drained.
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.
System Make-Up
Water loss from the system should be replaced from a make-up
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 supply even
through a non-return valve.
Alternative Methods of Filling Sealed System
METHOD A
HEATING
CIRCUIT
RETURN
STOP
VALVE
DOUBLE
CHECK
VALVE
ASSEMBLY
TEST COCK
ANTI-VACUUM
VALVE
HOSE
UNIONS
MAINS
WATER
SUPPLY
TEMPORARY
HOSE
HEATING
SYSTEM
(RETURN)
STOP
VALVE
MAINS WATER
SUPPLY
CISTERN &
OVERFLOW
PRESSURE PUMP &
REDUCING VALVE IF
REQUIRED
FIG 7

Aztec Classic Electric Boilers
9
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
9. Multiple Boiler Installations
Important
Where a greater output is required, more than one boiler can be
used in the same system. However, if installing a circulating pump
with a higher power demand, the PCB circuit protection fuse may
not be adequate. The pump could be wired using a relay. See wiring
instructions (Page 12, Fig 13-15) for further details.
The boilers must be fitted side by side using common flow and
returns. For each additional boiler fitted, it is recommended that the
pipe work is increased in size and the pump set to deliver the
combined flow rates. The circulating pump will be connected to one
of the boilers or via the relay.
We strongly recommend the positioning of isolation valves on the
flow and return pipe work of each boiler, as there may be a need to
isolate one or more during servicing (see Fig.9).
Please contact the Technical Support team for further information.
FIG 8
Ø28mm
Ø28mm
Ø35mm
Ø22mm
Ø22mm
Ø22mm
Ø22mm
Ø22mm
Ø22mm
Ø35mm
Ø28mm
Ø22mm
Flow
Drain
Valve
Min. Flow
Rate
FIG 9

Aztec Classic Electric Boilers
10
Ø22mm
500mm (min)
Open vented
F&E Tank
arrangement
Auto air vent
Auto air vent
Ø15mm
3 port valve
PUMP
Service valve
Aztec Boiler
DHW Cylinder
FLOW
RETURN
Service valve
Drain
valve
Expansion
Ø22mm
Feed
Ø15mm
ALTERNATIVE
Auto
bypass
Bypass must
dissipate heat and
be 22mm diameter
min x 1.5m
Open Vent System
FIG 10
Sealed System
FIG 11
Drain
valve
Service
valve
PUMP
Expansion
vessel
Safety
valve
Pressure
Gauge
Auto
bypass
valve
Bypass must
dissipate heat and
be 22mm diameter
min x 1.5mtr
Service
valve
Alternative
pump position
Aztec Boiler
Auto air
vent
Auto air
vent
3 port
valve
DHW
Cylinder
Central heating
FLOW
RETURN

Aztec Classic Electric Boilers
11
10. Wiring Instructions
ALL ELECTRICAL WORKMUST BE CARRIED OUT IN ACCORDANCE
WITH CURRENT IEE WIRING REGULATIONS.
BEFORE COMMENCING INSTALLATION CHECK POWER SUPPLY TO
THE PROPERTY TO ENSURE THAT THERE IS SUFFICIENT CURRENT
AND VOLTAGE AVAILABLE FOR SIZE OF BOILER BEING FITTED. TAKE
INTO ACCOUNT REQUIREMENTS OF OTHER ELECTRICAL
APPLIANCES. THE BOILER MUST BE CONNECTED TO THE MAINS
SUPPLY BY MEANS OF A DOUBLE POLE LINKED SWITCH 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.
Important:
The electrical supply requirements:-
The 2kW boilers and 6kW boiler supplies should meet the
requirements of EN 61000-3.3.
The 9kW and 11kW boilers must be installed in premises having a
service supply of ≥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 0.1939+ 0.1939Ω.
A double pole RCD with 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) MUST be fitted between RCD unit
and boiler and RCD and any external controls. Refer to technical
specification. For MCB ratings refer to wiring diagram.
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 APPLIANCE MUST BE EARTHED.
The mains connection block is located inside the boiler on a bracket
at the top 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. This is important as the pump is controlled by a
switched neutral. This also applies to pumps being controlled by a
relay.
IMPORTANT: CORRECT POLARITY MUST BE OBSERVED WHEN
BRINGING THE MAINS SUPPLY INTO THE BOILER.
ORANGE
GREY
BOILER PCB CONTROL
TERMINAL
BLOCK
SL L
N L
MAINS
RED
RED
BLUE
BROWN
L N
CH
ON
WIRING FOR EXTERNAL PROGRAMMER
FIG. 12

Aztec Classic Electric Boilers
12
Wiring Instructions (continued)
3 Phase Supply Connections for 2 or more Boilers
MAINS SUPPLY CABLES
Connect each boiler to each phase.
CONTROL SIGNAL
Wire as shown in wiring diagram.
PUMP CONNECTIONS
The pump to be connected to one boiler only.
See wiring diagram.
IMPORTANT: ALL ELECTRICAL CONNECTIONS SHOULD BE CHECKED,
LOOSE CONNECTIONS CAN CAUSE PROBLEMS.
WARNING: THIS APPLIANCE MUST BE EARTHED.
1. Any exposed pipe work must be earthed in accordance
with IEE regulations.
2. On completion of installation all electrical work must be
tested to IEE regulations and NICEIC inspection and
completion certificate must be issued.
RELAY
CONTROLLER
PUMP
GREEN/YELLOW
BLUE
RED
RED
BLUE
G/Y
E
RED
FIG. 13
E
N
L
PUMP
BOARD 1
PUMP WIRING FOR MULTIPLE
BOILER INSTALLATION
GREY
ORANGE
230V SUPPLY
CALL TERMINAL
(BOILER)
RED
PLEASE NOTE: THIS LIVE SUPPLY
CAN ONLY RE USED FOR THIS
WIRING CONFIGURATION. ANY
OTHER USE MAY RESULT IN
DAMAGE TO THE PCB.
PROGRAMMABLE ROOM
STAT
FIG. 14
FIG. 15
WIRING FOR EXTERNAL PROGRAMMER
CONTROLLING 3 BOILERS ON A 3 PHASE SUPPLY
CALL BOARD 1
CALL BOARD 2
CALL BOARD 3
BROWN
BLACK
GREY
A B C
RELAY
CONTROLLER
PROGRAMMER
L N
CH
ON
HW
ON
CH
OFF
HW
OFF

Aztec Classic Electric Boilers
13
Blue
Red
Blue
Brown
G/Y
Brown
Blue
G/Y
Blue
Grey
Orange
Brown
Red
G/Y
Blue
Brown
Brown
Blue
Red
Red
Orange
PUMP
L N
RCD UNIT
MCB
MCB
PCB CONTROL
L L
SL L
N L
EARTH
CONSUMER UNIT
TERMINAL BLOCK
ROOM THERMOSTAT
PROGRAMMER
L
N
CH ON
WIRING DIAGRAM FOR HEATING ONLY
FIG. 16
2
3
4
5
6
7
8
9
10
1

Aztec Classic Electric Boilers
14
PUMP
Blue
PCB CONTROL
L
L
Red
Brown
Blue
G/Y
Blue
Red
G/Y
Brown
Blue
G/Y
Blue
Brown
Brown
Blue
Brown
G/Y
Orange
Grey
Red
G/Y
Brown
Blue
Red
Orange
Red
Black
Orange
Red
Orange
Brown
Grey
G/Y
Blue
Grey
Blue
G/Y
Brown
Orange
RCD UNIT
MCB
MCB
CONSUMER UNIT
EARTH
L
N
CH
ON
HW
ON
CH
OFF
HW
OFF
PROGRAMMER
1
2
3
4
5
6
7
8
9
10
ROOM THERMOSTAT
CYLINDER THERMOSTAT
SL L
WIRING DIAGRAM FOR S PLAN CONTROL SYSTEM
FIG. 17
L N
MOTORISED
VALVE
(DHW)
N E L C SL
N E L C SL
MOTORISED
VALVE
(HEATING)

Aztec Classic Electric Boilers
15
PUMP
Brown
Blue
G/Y
Blue
Red
Blue
L N
Red
G/Y
Brown
Blue
Grey
Orange
Green/Yellow
Blue
Brown
Brown
Blue
Brown
RCD UNIT
MCB
MCB
PCB CONTROL
L L
CONSUMER UNIT
EARTH
SL L
Red
Brown
Blue
Red
Orange
Black
G/Y
Blue
Green/Yellow
Orange
Black
Grey
Red
Orange
Black
Black
Red
1 2 3 4 5 6 7 8 9 10
PROGRAMMER
L
N
CH
ON
HW
ON
CH
OFF
HW
OFF
DIVERTER
VALVE
WIRING DIAGRAM FOR Y PLAN CONTROL SYSTEM
FIG. 18

Aztec Classic Electric Boilers
16
FIG. 19
This link needs to be left connected on installation.








GRN/YE L
ELEMENT 1
ELEMENT 2
ELEMENT 3
ELEMENT 4
L1
L2
L3
L4
ELEMENT 1
ELEMENT 2
ELEMENT 3
ELEMENT 4
1 ELEMENT
2 ELEMENTS
3 ELEMENTS
4 ELEMENTS
JUMPER POSITIONS
FRONT OF BOARD
LE N
RED
RED
RED
RED
EARTH
L
L
N
N
PUMP TERMINAL
BLOCK
BLUE
RED
GRN/YE L
BLUE
HL STAT
RED
RED
HIGH LIMIT THERMOSTAT
L4
L3
THERMISTER
L2
L1
SL
L
CALL BLOCK
ORANGE
GREY
L L

Aztec Classic Electric Boilers
17
11. Servicing Instructions
To ensure reliable operation of your Aztec electric 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 the mains supply before carrying out any service work.
1. Check all electrical connections on PCB and electric
elements to ensure they are secure and clean.
2. Check electrical insulation on wiring.
3. Ensure all air grilles are clean and free from obstructions.
4. Inspects seals around elements and also the heat
exchanger top and bottom flanges.
12. Parts Replacement
11.1 Casing Removal
IMPORTANT
Isolate the mains electrical supply to the boiler before carrying out
any maintenance work.
1. Isolate electrical supply to the boiler.
2. Remove 4 fixing screws securing front casing in position.
3. Slide top casing upwards this will allow front casing to slide
forward.
IMPORTANT: All electrical connections should be checked. Loose
connections can cause problems.
This boiler is fitted with a manual reset high limit thermostat. Before
replacing any part, ensure that the thermostat does not require re-
setting.
11.2 PCB Assembly Replacement
1. Ensure electrical supply is isolated to the boiler.
2. Remove the 4 fixing screws and washers (2 at top and 2 at
bottom), lift up the top-plate and carefully slide off the front
casing panel.
3. Disconnect the pump + call plug, the thermistor plug and the
high limit stat plug.
4. Disconnect all element cables apart from the rear element. N.B.
Take note of wiring arrangement before disconnecting.
5. Now remove the grey pipe insulation, it is now possible to
disconnect the remaining element.
6. With all elements disconnected, again taking note of wiring
arrangement, carefully disconnect and remove the element
cables from the PCB.
7. IMPORTANT: Care MUST be taken when handling the PCB.
8. For ease of access disconnect from the main terminal block
both the red + black cables and also the power input cables,
leaving the earth cable connected.
9. Free both the pump and call terminal blocks by removing the
terminal block fixing screws.
10. Finally remove the 4 fixing screws holding the PCB to the
bracket.
11.3 High Limit Thermostat Replacement
1. Ensure electrical supply is isolated to the boiler.
2. The high limit thermostat can be found fixed to top front
face of boiler.
3. Remove 2 terminal connectors from high limit thermostat,
loosen retaining straps and slide thermostat out from
behind.
4. IMPORTANT: When replacing the thermostat ensure a
heat sink compound is used between back of thermostat
and face of the boiler (See Fig. 21 for positioning).
5. Inspect retaining straps and replace where necessary.
11.4 Thermostat Replacement
1. Isolate the electrical supply to the boiler.
2. Thermistor is located fixed to the top front of the boiler
above the high limit thermostat.
3. Disconnect from the PCB and slide out from behind the
retaining strap.
4. IMPORTANT: When replacing the thermistor ensure a heat
sink compound is used between the thermistor and boiler
body (See Fig 21 for positioning).
5. Inspect retaining strap and replace where the necessary.
6. When replacing the front casing, ensure the thermostat
control shaft passes through the hole in the front control
panel.
FIXING SCREWS
TOP AND BOTTOM
4 FIXING
SCREWS
PCB
CONTROL
UNIT
FIG. 20

Aztec Classic Electric Boilers
18
11.5 Element Replacement
1. Isolate electrical supply to the boiler.
2. Drain down the system.
3. Disconnect the terminal connectors from the high limit
thermostat.
4. Remove thermistor from behind the retaining strap.
5. Disconnect electrical elements and earth wire.
6. Disconnect compression fitting top and bottom of boiler.
7. Remove securing bracket on bottom of the boiler then carefully
remove the top bracket.
8. Boiler unit can now be carefully removed.
9. Remove eight fixing screws on top flange and withdraw
element assembly.
10. Remove bottom element positioning bracket.
11. Remove damaged element.
12. Refit in reverse order, ensure element seals are fitted.
13. Check for continuity through two terminals on each element.
IMPORTANT
Inspect all seals and change where necessary.
11. 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 to check the
continuity across the terminals of the thermostat.
To reset press red button in the centre of the thermostat.
Thermostat may have tripped due to one of the following:-
1. Faulty circulation pump.
2. Isolation valve on system closed.
3. Air trapped in system.
4. Out of calibration limit thermostat.
5. Temperature settings on PCB incorrect.
6. 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 Wring
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 connection 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.
Jumpers
Are the jumpers set correctly (see Fig. 19).
Green LED
If the green LED is illuminated but the boiler is not functioning,
check that any external controls fitted are calling for heat.
Blown fuse on Board
If there is power to the boiler but no LED illuminated then the fuse
on the PCB may have blown. The fuse is located at the top edge of
the PCB. (Fuse type 20mm 1A anti-surge Bessman type S560). The
fuse may have blown due to one of the following:-
1. When multiple boilers are fitted and a larger pump is used.
2. If the call terminal block is used to supply power to any
ancillary controls.
RCD Unit Trips
Check that the RCD unit is correctly rated for the boiler size. If under
sized then change.
Inspect the mains terminal block for earth continuity, if the element
is found to be faulty then fit a new element.
Thermistor Values
Temperature
Resistor Value
0
32554
5
25339
10
19872.2
15
15698.5
20
12487.7
25
10000
30
8069.1
35
6534.7
40
5329.9
45
4371.7
50
3605.3
55
2988.7
60
2490
65
2084.4
70
1753
75
1480.9
FIG. 20

Aztec Classic Electric Boilers
19
NO HEAT –PERMANENT GREEN LIGHT
IS THE
PROGRAMMER
TURNED ON I.E.
CALL SIGNAL?
CHECK
EXTERNAL
CONTROLS ARE
CALLING FOR
HEAT
IS CALL WIRE LIVE I.E. LINE
VOLTAGE?
CHECK
ELECTRIC
SYSTEM
CIRCUIT
NO
YES
NO
IS THE HEAT EXCHANGER
GETTING UP TO
TEMPERATURE –AMBER ON
OR FLASHING
CHANGE PCB
YES
NO
YES
ARE ISOLATING
VALVES OPEN?
NO
OPEN ISOLATING
VALVES
YES
IS THE PUMP
RUNNING?
YES
CHECK SYSTEM
PRESSURE &
PIPE WORK FOR
AIR LOCKS
NO
CHECK LIVE &
NEUTRAL TO PUMP
LIVE & NEUTRAL
OK?
CHANGE PUMP

Aztec Classic Electric Boilers
20
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