Trianco Aztec CLASSIC 2KW, Aztec CLASSIC 9KW, Aztec CLASSIC 11KW, Aztec CLASSIC 6KW, Aztec CLASSIC 12KW Installation, Operation And Servicing Instructions

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

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 RE­FITTED 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 100cm2 will 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 pre­pressurisation 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
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

L E N

RED

RED

RED

RED

EARTH L L N N

PUMP TERMINAL

BLOCK

BLUE

RED

GRN/YEL 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 re­setting.

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

Aztec Classic Electric Boilers

21

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 Classic Electric Boilers

22

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 Classic Electric Boilers

23

Aztec Classic Electric Boilers

24

ITEM

DESCRIPTION

QTY

2kW

6kW

9kW

11kW

12kW

1

Heat Exchanger Assembly

1

221881

221882

221883

221884

221880

2

PCB Assembly

1

3

Element

1 3

3

3 1

4 4

Thermistor

1

6

Tube Insulation

1 7

Back Casing Assembly

1

8

Front Casing Assembly

1 9

Bottom Pipe Bracket

1

10

Pipe Bracket

1 11

High Limit Thermostat

1

12

Jubilee Clip

2

13

Cable Gland

1 14

Locknut

1

15

Gasket

1 16

22mm Pipe Insulation

1

17

Duct Top

1 18

Top Pipe Bracket

1

19

Top Cap

1

20

Snap In Protection Grommet

1 22

Cable Gland

1

23

Locknut

1 24

Label Call

1

25

Label Pump

1 26

Terminal Block

1

27

Fuse 1A

1

28

Switch Assembly

1

Wiring Harness

1

Aztec Classic Electric Boilers

25

Aztec Classic Electric Boilers

26

T R Engineering Ltd

Unit 7, Newton Chambers Way

Thorncliffe Industrial Estate

Chapeltown

Sheffield

S35 2PH

Tel: [phone]
Fax: [phone]

E-mail: [email protected]

Web: www.trianco.co.uk

© T R Engineering Ltd

Copyright in this brochure and the drawings and illustrations contained in it is vested in T R Engineering Ltd and neither the

brochure nor any part thereof may be reproduced without prior written consent.

T R Engineering Ltd’s policy is one of continuous research and development. This may necessitate alterations to this specification.

221827 May 2014