vokera Unica 28 HE User guide

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Page 1

Unica HE

High efficiency combi boiler

Installation

& Servicing

Instructions

THESE INSTRUCTIONS TO BE RETAINED BY USER

Vokèra is a licensed member of the Benchmark scheme which aims to improve the standards of installation and commissioning of domestic hot water systems in the UK.

Page 2

Contents

Design principles & operating sequence Page

1.1 Principle components 3

1.2 Mode of operation (at rest) 3

1.3 Mode of operation (heating) 3

1.4 Mode of operation (Hot water) 3

1.5 Safety devices 3

Technical data Page

2.1 Central heating 4

2.2 Domestic hot water 4

2.3 Gas pressures 4

2.4 Expansion vessel 4

2.5 Dimensions 4

2.6 Clearances 4

2.7 Connections 4

2.8 Electrical 4

2.9 Flue details (concentric) 4

2.9A Flue details (twin pipes) 4

2.9B Flue details (80/125) 4

2.10 Efficiency 4

2.11 Emissions 4

2.12 Pump duty 5

General requirements (UK) Page

3.1 Related documents 6

3.2 Location of appliance 6

3.3 Gas supply 6

3.4 Flue system 6

3.5 Air supply 6

3.6 Water circulation 6

3.7 Electrical supply 7

3.8 Mounting on a combustible surface 7

3.9 Timber framed buildings 7

3.10 Inhibitors 7

3.11 Showers 7

Servicing Page

6.1 General 18

6.2 Routine annual servicing 18

6.3 Replacement of components 18

6.4 Component removal procedure 18

6.5 Pump assembly 18

6.6 Safety valve 19

6.7 Lower automatic air release valves 19

6.8 Water pressure switch 19

6.9 Primary thermistor 19

6.10 Return thermistor 19

6.11 Printed circuit board 19

6.12 Gas valve 19

6.13 Electrodes and condense sensor 20

6.14 Flue fan & mixer 20

6.15 Burner 20

6.16 Main heat exchanger 20

6.17 Automatic by-pass 21

6.18 Expansion vessel 21

6.19 Condense trap removal 21

6.20 Flue collector removal 21

Checks, adjustments and fault finding Page

7.1 Checking appliance operation 23

7.2 Appliance modes of operation 23

7.3 Appliance fan speed 24

7.4 Checking the CO2 & adjusting the valve 24

7.5 Combustion analysis test 25

7.6 Checking the expansion vessel 25

7.7 External faults 25

7.8 Electrical checks 25

7.9 Fault finding 26

7.10 Component values & characteristics 26

7.11 Final fault codes 26

7.12 Boiler configuration 26

General requirements (EIRE) Page

3A.1 Related documents 8 3A.2 Location of appliance 8 3A.3 Gas supply 8 3A.4 Flue system 8 3A.5 Air supply 8 3A.6 Water circulation 8 3A.7 Electrical supply 9 3A.8 Mounting on a combustible surface 9 3A.9 Timber framed buildings 9 3A.10 Inhibitors 9 3A.11 Showers 9 3A.12 Declaration of conformity 9

Installation Page

4.1 Delivery 10

4.2 Contents 10

4.3 Unpacking 10

4.4 Preparation for mounting the appliance 10

4.5 Fitting the flue 10

4.6 Connecting the gas & water 14

4.7 Electrical connections 15

Commissioning Page

5.1 Gas supply installation 16

5.2 The heating system 16

5.3 Initial filling of the system 16

5.4 Initial flushing of the system 16

5.5 Pre-operation checks 16

5.6 Initial lighting 16

5.7 Checking gas pressure & combustion analysis 16

5.8 Final flushing of the heating system 17

5.9 Setting the boiler operating temperature 17

5.10 Setting the system design pressure 17

5.11 Regulating the central heating system 17

5.12 Final checks 17

5.13 Instructing the user 17

Wiring diagrams Page

8.1 External wiring 27

8.2 Typical control applications 27

8.3 Other devices 27

8.4 Vokera twin-channel programmer 27

Exploded diagrams Page

9.1 Table 1 29

9.2 Table 2 30

9.3 Table 3 31

9.4 Table 4 32

9.5 Table 5 33

L.P.G. instructions Page

10.1 Related documents 34

10.2 Technical data 34

10.3 Converting the appliance gas type 34

10.4 Gas supply 34

10.5 Gas supply installation 34

10.6 Adjusting the gas valve 34

10.7 Appliance fan speed 35

Benchmark 36

Page 3

INTRODUCTION

The Unica HE comprises a range of high-efficiency combination boilers with outputs to DHW of 28kW, 32kW, and 36kW respectively. These appliances – by design – incorporate electronic ignition, circulating pump, expansion vessel, safety valve, pressure gauge, and automatic by-pass.

The Unica range is produced as room sealed, category II2H3P appliances, suitable for internal wall mounting applications only. Each appliance is provided with a fan powered flue outlet with an annular co-axial combustion air intake that can be rotated – horizontally – through 360 degrees for various horizontal or vertical applications. The

fig. 1

R F G O I

Unica HE can also be used with the Vokera twin flue system. The Unica HE is approved for use with C13 & C33 type flue applications. These appliances are designed for use with a sealed system only; consequently they are not intended for use on open vented systems.

This booklet is an integral part of the appliance. It is therefore necessary to ensure that the booklet is handed to the person responsible for the property in which the appliance is located/installed. A replacement copy can be obtained from Vokera customer services.

General layout (fig. 1)

1 Three porte valve actuator 2 Drain valve 3 Safety valve 4 Pressure switch 5 Pump 6 Bottom auto air vent (AAV) 7 Injector 8 Condense trap 9 Return sensor 10 Flue gas analysis test point 11 Flue outlet & air intake 12 Ignition transformer 13 Top AAV 14 Flow sensor 15 High limit thermostat 16 Limit thermostat 17 Sensing Electrode 18 Spark Electrode 19 Cylindric Burner 20 Condensate level sensor 21 Main heat exchanger 22 Top AAV pipe 23 Fan assembly 24 Mixer 25 Expansion vessel 26 Domestic hot water sensor 27 Domestic hot water heat exchanger 28 DHW flow switch 29 Gas valve 30 Condensing drain

R Heating return connection F Heating flow connection G Gas connection O Hot water outlet I Cold water inlet

R F G O I

The Unica HE is approved for use with C13 & C33 type flue applications.

Page 4

DHW

TEMPERATURE

SELECTOR

HYDROMETRE

Fig. 1A

GREEN LED

2-digit LED

display

RED LED

MODE SELECTOR

SWITCH

HEATING

TEMPERATURE

SELECTOR

Hot water only Select this position if you want the boiler to supply hot water only (no heating)

Boiler at OFF/standby Select this position when you want the boiler to be switched off or short

periods (days) or if the boiler requires to be reset (refer to users handbook)

Heating & hot water (economy) Select this position when you want the boiler to respond to a heating request

from the time-clock/programmer

Heating & hot water with pre-heat Select this position when you want the boiler to respond to a heating request

from the time-clock/programmer (comfort) and you want the domestic hot water to be pre-heated

DHW temperature selector Move the selector clockwise to increase the hot water outlet temperature, or

counter-clockwise to reduce the temperature

Heating temperature selector Move the selector clockwise to increase the heating outlet temperature, or

counter-clockwise to reduce the temperature

2-digit LED display Displays the current outlet temperature of the boiler. During a fault condition,

the appropriate fault code will be displayed (refere to the users handbook for instructions regarding fault codes)

Green LED lit Boiler is working/responding to a heating/hot water request

Red LED lit Boiler has identified a fault and has failed-safe. Refer to users handbook for

instructions on how to reset

Pressure gauge Ensure the system pressure is set correctly (minimum 0.5-bar)

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SECTION 1 DESIGN PRINCIPLES AND OPERATING SEQUENCE

1.1 PRINCIPLE COMPONENTS

• A fully integrated electronic control board featuring electronic temperature control, anticycle control, pump over-run, self-diagnostic fault indicator, full air/gas modulation.

• Radial aluminium heat exchanger.

• Electronic ignition with flame supervision

• Integral high-head pump

• Fan

• Expansion vessel

• Water pressure switch

• Condensate level sensor

• Pressure gauge

• Safety valve

1.2 MODE OF OPERATION (at rest)

When the appliance is at rest and there are no requests for heating or hot water, the following functions are active:

• Frost-protection system – the frost-protection system protects the appliance against the risk of frost damage both for CH and DHW. For CH line, if the main temperature falls to 6°C, the appliance will function on minimum power until the temperature on main reaches 35°C. Moreover if the DHW temperature falls to 4°C, the appliance will function on minimum power until the temperature on main reaches 55°C.

• Anti-block function – the anti-block function enables the pump and divertor valve actuator to be energised for short periods, when the appliance has been inactive for more than 24hours.

1.3 MODE OF OPERATION (Heating)

When there is a request for heat via the time clock and/or any external control, the pump and fan are started, the fan speed will modulate until the correct signal voltage is received at the control PCB. At this point an ignition sequence is enabled.

electronic circuitry increases the gas rate to maximum or will modulate output to stabilise the temperature.

In the event of the appliance exceeding the desired temperature (set point) the burner will shut down until the temperature drops. When the request for DHW has been satisfied the appliance pump and fan may continue to operate to dissipate any residual heat within the appliance.

1.5 SAFETY DEVICES

When the appliance is in use, safe operation is ensured by:

• A water pressure switch that monitors system water pressure and will de-activate the pump, fan, and burner should the system water pressure drop below the rated tolerance.

• Fan speed sensor to ensure safe operation of the burner

• A high limit thermostat that over-rides the temperature control circuit to prevent or interrupt the operation of the burner.

• Flame sensor that will shut down the burner when no flame signal is detected.

• A sensor that interrupts the operation of the appliance if the condense pipe becomes blocked.

• A safety valve which releases excess pressure from the primary circuit.

Return

temperature

sensor

Top AAV

Flow temperature

sensor

Main heat

exchanger

Ignition is sensed by the electronic circuit to ensure flame stability at the burner. Once successful ignition has been achieved, the electronic circuitry increases the gas rate to 75% for a period of 15 minutes. Thereafter, the boiler’s output will either be increase to maximum or modulate to suit the set requirement.

When the appliance reaches the desired temperature the burner will shut down and the boiler will perform a three-minute anti-cycle (timer delay). When the request for heat has been satisfied the appliance pump and fan may continue to operate to dissipate any residual heat within the appliance.

1.4 MODE OF OPERATION (Hot water)

When there is a request for DHW via a hot water outlet or tap, the pump and fan are started, the fan speed will modulate until the correct signal voltage is received at the control PCB. At this point an ignition sequence is enabled.

Ignition is sensed by the electronic circuit to ensure flame stability at the burner. Once successful ignition has been achieved, the

Expansion

vessel

Fig. 2

Pump

Diverter

valve

Automatic

by-pass

Safety

valve

Bottom

AAV

return

Pressure

switch

Drain valve

flow

DHW

non return

valve

DHW heat exchanger

DHW

outlet

DHW

temperature

sensor

DHW flow

DHW

inlet

Flow

regulator

switch

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SECTION 2 TECHNICAL DATA

2.1 Central Heating Unica 28HE Unica 32HE Unica36HE

Heat input (kW) 20 25 30 Maximum heat output (kW) 60/80°C 19.6 24.45 29.31 Minimum heat output (kW) 60/80°C 5.9 6.9 6.84 Maximum heat output (kW) 30/50°C 21.00 26.30 31.83 Minimum heat output (kW) 30/50°C 6.40 7.47 7.41 Minimum working pressure 0.5 bar Maximum working pressure 2.7 bar Minimum flow rate 350 l/h

2.2 Domestic Hot Water Unica 28HE Unica 32HE Unica36HE

Heat input (kW) 28 32 36 Flow Rate: ∆T35oC 11.5 l/pm 13.1 l/pm 14.7 l/pm Maximum inlet pressure 6.0 bar Minimum inlet pressure 0.15 bar Minimum flow rate 2.0 l/min

2.3 Gas Pressures Unica 28HE Unica 32HE Unica36HE

Inlet pressure (G20) 20.0 mbar Heating maximum gas rate (m3/hr) 2.12 2.64 3.17 DHW maximum gas rate (m3/hr) 2.96 3.38 3.81 Minimum gas rate (m3/hr) 0.63 0.74 0.74 Injector size (mm) 6.7 6.7 7.0

2.4 Expansion Vessel Unica 28HE Unica 32HE Unica36HE

Capacity 8-litres 10-litres 10-litres Maximum system volume 76-litres 91-litres 91-litres Pre-charge pressure 1.0 bar

2.5 Dimensions Unica 28HE Unica 32HE Unica36HE

Height (mm) 780 780 780 Width (mm) 400 450 450 Depth (mm) 358 358 358 Dry weight (kg) 40 42 45

2.6 Clearances UNICA HE Range

Sides 12mm Top 150mm from casing or 25mm above flue elbow (whichever is applicable) Bottom 150mm Front 600mm

2.7 Connections UNICA HE Range

Flow & return 22mm Gas 15mm DHW hot & cold 15mm Safety valve 15mm Condense 21mm

2.8 Electrical Unica 28HE Unica 32HE Unica36HE

Power consumption (Watts) 150W 150W 150W Voltage (V/Hz) 230/50 Internal fuse 3.15A T (for PCB) - 3.15A F (for connections block) External fuse 3A

2.9 Flue Details (concentric) Unica 28HE Unica 32HE Unica36HE

Maximum horizontal flue length (60/100mm) 7.8m 7.8m 7.8m Maximum vertical flue length (60/100mm) 8.8m 8.8m 8.8m Maximum horizontal flue length (80/125mm) 20m 20m 20m Maximum vertical flue length (80/125mm) 25m 25m 25m

2.9A Flue Details (twin pipes) Unica 28HE Unica 32HE Unica36HE

Maximum horizontal flue length (80mm/80mm) 40m/40m 35m/35m 35m/35m Maximum vertical flue length (80mm/80mm) 40m/40m 35m/35m 35m/35m

2.10 Efficiency Unica 28HE Unica 32HE Unica36HE SEDBUK (%) 90.3 90.2 90.1

2.11 Emissions Unica 28HE Unica 32HE Unica36HE

CO2 @ maximum output (%) 9.0 9.0 9.0 CO2 @ minimum output (%) 9.0 9.0 9.0 CO/CO2 ratio @ maximum output 0.002 to 1 0.002 to 1 0.002 to 1 CO/CO2 ratio @ minimum output 0.0004 to 1 0.0004 to 1 0.0004 to 1 CO @ maximum output (mg/kWh) 182.8 215.0 215.0 CO @ minimum output (mg/kWh) 53.8 32.3 32.3 NOx @ maximum output mg/kWh) 105.9 105.9 88.3 NOx @ minimum output (mg/kWh) 61.8 61.8 70.6 NOx rating class 5 class 5 class 5

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2.12 PUMP DUTY

Fig. 3 shows the flow-rate available – after allowing for pressure loss through the appliance – for system requirements. When using this graph, apply only the pressure loss of the system. The graph is based on a 20oC temperature differential.

Fig. 3

5,0

4,8

4,6

4,4

4,2

4,0

3,8

3,6

3,4

3,2

3,0

2,8

2,6

2,4

2,2

2,0

1,8

1,6

1,4

1,2

1,0

Residual head (x 100 mbar)

0,8 0,6

0,4

0,2

0,0

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500

1st speed

2nd speed

3rd speed

Flow rate (l/h)

Fig. 4

Key Location Minimum distance

A Below an opening (window, air-brick, etc.) 300 mm B Above an opening (window, air-brick, etc.) 300 mm C To the side of an opening (window, air-brick, etc.) 300 mm D Below gutter, drain-pipe, etc. 25 mm E Below eaves 25 mm

F Below balcony, car-port roof, etc. 25 mm G To the side of a soil/drain-pipe, etc. 25 mm H From internal/external corner or boundary 300 mm

I Above ground, roof, or balcony level 300 mm J From a surface or boundary facing the terminal 1200 mm K From a terminal facing a terminal 1200 mm L From an opening in the car-port into the building 1200 mm

M Vertically from a terminal on the same wall 1500 mm N Horizontally from a terminal on the same wall 300 mm

P From a structure to the side of the vertical terminal 500 mm

Q From the top of the vertical terminal to the roof flashing As determined by the fixed collar

of the vertical terminal

Page 8

SECTION 3 GENERAL REQUIREMENTS (UK)

This appliance must be installed by a competent person in accordance with the Gas Safety (Installation & Use) Regulations.

3.1 RELATED DOCUMENTS

The installation of this boiler must be in accordance with the relevant requirements of the Gas Safety (Installation & Use) Regulations, the local building

the appliance gas inlet connection must not be used. The installation must be tested for soundness in accordance with BS6891.

If the gas supply serves more than one appliance, it must be ensured that an adequate supply is maintained to each appliance when they are in use at the same time.

regulations, the current I.E.E. wiring regulations, the bylaws of the local water undertaking, the Building Standards (Scotland) Regulation, and Building Standards (Northern Ireland) Regulations.

3.4 FLUE SYSTEM

The terminal should be located where the dispersal of combustion products is not impeded and with due regard for the damage and discoloration that

It should be in accordance also with any relevant requirements of the local authority and the relevant recommendations of the following British Standard

may occur to building products located nearby. The terminal must not be located in a place where it is likely to cause a nuisance (see fig. 4).

Codes of Practice.

In cold and/or humid weather, water vapour will

3.2 LOCATION OF APPLIANCE

The appliance may be installed in any room or

condense on leaving the terminal; the effect of such pluming must be considered.

internal space, although particular attention is drawn to the requirements of the current I.E.E. wiring regulations, and in Scotland, the electrical provisions of the Building Regulations, with respect to the installation of the appliance in a room or

If installed less than 2m above a pavement or platform to which people have access (including balconies or flat roofs) the terminal must be protected by a guard of durable material. The guard

internal space containing a bath or shower.

BS 5440 PART 1 FLUES BS 5440 PART 2 FLUES & VENTILATION BS 5449 PART 1 FORCED CIRCULATION HOT WATER SYSTEMS BS 5546 INSTALLATION OF GAS HOT WATER SUPPLIES FOR DOMESTIC PURPOSES BS 6798 INSTALLATION OF BOILERS OF RATED INPUT NOT EXCEEDING 60kW BS 6891 LOW PRESSURE INSTALLATION PIPES BS 7074 PART 1 APPLICATION, SELECTION, AND INSTALLTION OF EXPANSION VESSELS

AND ANCILLARY EQUIPMENT FOR SEALED WATER SYSTEMS

When an appliance is installed in a room or internal space containing a bath or shower, the appliance or any control pertaining to it must not be within reach of a person using the bath or shower.

The location chosen for the appliance must permit the provision of a safe and satisfactory flue and termination. The location must also permit an adequate air supply for combustion purposes and an adequate space for servicing and air circulation around the appliance. Where the installation of the appliance will be in an unusual location special procedures may be Necessary, BS 6798 gives detailed guidance on this aspect.

A compartment used to enclose the appliance must be designed and constructed specifically for this purpose. An existing compartment/cupboard may be utilised provided that it is modified to suit.

Details of essential features of compartment/ cupboard design including airing cupboard installations are given in BS 6798. This appliance is not suitable for external installation.

3.3 GAS SUPPLY

The gas meter – as supplied by the gas supplier – must be checked to ensure that it is of adequate size to deal with the maximum rated input of all the appliances that it serves. Installation pipes must be fitted in accordance with BS 6891.

Pipe work from the meter to the appliance must be of adequate size. Pipes of a smaller size than

must be fitted centrally over the terminal. Refer to BS 5440 Part 1, when the terminal is 0.5 metres (or less) below plastic guttering or 1 metre (or less) below painted eaves.

3.5 AIR SUPPLY

The following notes are intended for general guidance only.

This appliance is a room-sealed, fan-flued boiler, consequently it does not require a Permanent air vent for combustion air supply.

When installed in a cupboard or compartment, ventilation for cooling purposes is also not required.

3.6 WATER CIRCULATION

Detailed recommendations are given in BS 5449 Part 1 and BS 6798. The following notes are for general guidance only.

3.6.1 PIPEWORK

It is recommended that copper tubing to BS 2871 Part 1 is used in conjunction with soldered capillary joints. Where possible pipes should have a gradient to ensure air is carried naturally to air release points and that water flows naturally to drain cocks. Except where providing useful heat, pipes should be insulated to avoid heat loss and in particular to avoid the possibility of freezing. Particular attention should be paid to pipes passing through ventilated areas such as under floors, loft space, and void areas.

Page 9

3.6.2 AUTOMATIC BY-PASS

The appliance has a built-in automatic by-pass, consequently there is no requirement for an external by-pass, however the design of the system should be such that it prevents boiler ‘cycling’.

3.6.3 DRAIN COCKS

These must be located in accessible positions to facilitate draining of the appliance and all water pipes connected to the appliance. The drain cocks must be manufactured in accordance with BS 2879.

3.6.4 AIR RELEASE POINTS

These must be positioned at the highest points in the system where air is likely to be trapped. They should be used to expel trapped air and allow complete filling of the system.

3.6.5 EXPANSION VESSEL

The appliance has an integral expansion vessel to accommodate the increased volume of water when the system is heated. It can accept up to 8 (28HE) or 10 (32 & 36HE) litres of expansion from within the system, generally this is sufficient, however if the system has an unusually high water content, it may be necessary to provide additional expansion capacity (see 6.19).

3.6.6 FILLING POINT

A method for initial filling of the system and replacing water lost during servicing etc. directly from the mains supply, is provided (see fig. ). This method of filling complies with the current Water Supply (Water Fittings) Regulations 1999 and Water Bylaws 2000 (Scotland). If an alternative location is preferred, it should be connected as detailed in fig.5.

control

fig.5

flow/return

pipe

valve

temporary

connection

double

check valve

control

valve

supply

pipe

3.6.7 LOW PRESSURE SEALED SYSTEM

An alternative method of filling the system would be from an independent make-up vessel or tank mounted in a position at least 1 metre above the highest point in the system and at least 5 metres above the boiler (see fig. 5A).

The cold feed from the make-up vessel or tank must be fitted with an approved non-return valve and stopcock for isolation purposes. The feed pipe should be connected to the return pipe as close to the boiler as possible.

3.6.8 FREQUENT FILLING

Frequent filling or venting of the system may be indicative of a leak. Care should be taken during the installation of the appliance to ensure all aspects of the system are capable of withstanding pressures up to at least 3 bar.

Make-up vessel or tank

Automatic air-vent

Non-return

valve

fig.5A

Stopcock

5.0 metres minimum

Heating return

3.7 ELECTRICAL SUPPLY

The appliance is supplied for operation on 230V @ 50Hz electrical supply; it must be protected with a 3-amp fuse. The method of connection to the mains electricity supply must allow for complete isolation from the supply. The preferred method is by using a double-pole switch with a contact separation of at least 3

,5mm (3° high-voltage

category). The switch must only supply the

appliance and its corresponding controls, i.e. time clock, room thermostat, etc. Alternatively an unswitched shuttered socket with a fused 3-pin plug both complying with BS 1363 is acceptable.

3.8 MOUNTING ON A COMBUSTIBLE SURFACE If the appliance is to be fitted on a wall of combustible material, a sheet of fireproof material must protect the wall.

3.9 TIMBER FRAMED BUILDINGS

If the appliance is to be fitted in a timber framed building, it should be fitted in accordance with the Institute of Gas Engineers publication (IGE/UP/7) ‘Guide for Gas Installations in Timber Frame Buildings’.

3.10 INHIBITORS

Vokera recommend that an inhibitor - suitable for use with copper and aluminium heat exchangers

- is used to protect the boiler and system from the effects of corrosion and/or electrolytic action. The inhibitor must be administered in strict accordance with the manufacturers instructions*.

*Water treatment of the complete heating system

- including the boiler - should be carried out in accordance with BS 7593 and the Domestic Water Treatment Association’s (DWTA) code of practice.

3.11 SHOWERS

If the appliance is intended for use with a shower, the shower must be thermostatically controlled and be suitable for use with a combination boiler.

Page 10

SECTION 3A GENERAL REQUIREMENTS (EIRE)

This appliance must be installed by a competent person

in accordance with and defined by, the Standard Specification (Domestic Gas Installations) Declaration (I.S. 813).

3A.1 RELATED DOCUMENTS

The installation of this boiler must be in accordance with the relevant requirements of the local building regulations, the current ETCI National Rules for Electrical Installations, and the bylaws of the local water undertaking. It should be in accordance also with any relevant requirements of the local and/or district authority.

3A.2 LOCATION OF APPLIANCE

The appliance may be installed in any room or internal space, although particular attention is drawn to the requirements of the current ETCI National Rules for Electrical Installations, and I.S. 813, Annex K. When an appliance is installed in a room or internal space containing a bath or shower, the appliance or any control pertaining to it must not be within reach of a person using the bath or shower. The location chosen for the appliance must permit the provision of a safe and satisfactory flue and termination. The location must also permit an adequate air supply for combustion purposes and an adequate space for servicing and air circulation around the appliance. Where the installation of the appliance will be in an unusual location special procedures may be necessary, refer to I.S. 813 for detailed guidance on this aspect.

A compartment used to enclose the appliance must be designed and constructed specifically for this purpose. An existing compartment/cupboard may be utilised provided that it is modified to suit.

This appliance is not suitable for external installation.

such pluming must be considered. If installed less than 2m above a pavement or platform to which people have access (including balconies or flat roofs) the terminal must be protected by a guard of durable material. The guard must be fitted centrally over the terminal. Refer to I.S. 813, when the terminal is 0.5 metres (or less) below plastic guttering or 1 metre (or less) below painted eaves.

3A.5 AIR SUPPLY

The following notes are intended for general guidance only. This appliance is a room-sealed, fan-flued boiler, consequently it does not require a permanent air vent for combustion air supply.

When installed in a cupboard or compartment, ventilation for cooling purposes is also not required.

3A.6 WATER CIRCULATION

Specific recommendations are given in I.S. 813. The following notes are for general guidance only.

3A.6.1 PIPEWORK

It is recommended that copper tubing be used in conjunction with soldered capillary joints. Where possible pipes should have a gradient to ensure air is carried naturally to air release points and that water flows naturally to drain cocks. Except where providing useful heat, pipes should be insulated to avoid heat loss and in particular to avoid the possibility of freezing. Particular attention should be paid to pipes passing through ventilated areas such as under floors, loft space, and void areas.

3A.6.2 AUTOMATIC BY-PASS

The appliance has a built-in automatic by-pass, consequently there is no requirement for an external by-pass, however the design of the system should be such that it prevents boiler ‘cycling’.

3A.3 GAS SUPPLY

Pipe work from the meter to the appliance must be of adequate size. Pipes of a smaller size than the appliance gas inlet connection must not be used. The installation must be tested for soundness in accordance with I.S. 813.

If the gas supply serves more than one appliance, it must be ensured that an adequate supply is maintained to each appliance when they are in use at the same time.

3A.4 FLUE SYSTEM

The terminal should be located where the dispersal of combustion products is not impeded and with due regard for the damage and discoloration that may occur to building products located nearby. The terminal must not be located in a place where it is likely to cause a nuisance (see I.S. 813). In cold and/or humid weather, water vapour will condense on leaving the terminal; the effect of

3A.6.3 DRAIN COCKS

These must be located in accessible positions to facilitate draining of the appliance and all water pipes connected to the appliance.

3A.6.4 AIR RELEASE POINTS

These must be positioned at the highest points in the system where air is likely to be trapped. They should be used to expel trapped air and allow complete filling of the system.

3A.6.5 EXPANSION VESSEL

3A.6.6 FILLING POINT

A method for initial filling of the system and replacing water lost during servicing etc. is provided (see fig.8). You should ensure this method of filling complies with the local water authority regulations.

Page 11

3A.6.7 LOW PRESSURE SEALED SYSTEM

3A.6.8 FREQUENT FILLING

3A.7 ELECTRICAL SUPPLY

,5 mm (3° high-voltage

category). The switch must only supply the

appliance and its corresponding controls, i.e. time clock, room thermostat, etc.

fig. 6

115

114

3A.8 MOUNTING ON A COMBUSTIBLE SURFACE

If the appliance is to be fitted on a wall of combustible material, a sheet of fireproof material must protect the wall.

3A.9 TIMBER FRAMED BUILDINGS

If the appliance is to be fitted in a timber framed building, it should be fitted in accordance with I.S. 813 and local Building Regulations.

The Institute of Gas Engineers publication (IGE/ UP/7) ‘Guide for Gas Installations in Timber Frame Buildings’ gives specific advice on this type of installation.

3A.10 INHIBITORS

Vokera recommend that an inhibitor - suitable for use with aluminium heat exchangers - is used to protect the boiler and system from the effects of corrosion and/or electrolytic action. The inhibitor must be administered in strict accordance with the manufacturers instructions*.

*Water treatment of the complete heating system

- including the boiler - should be carried out in accordance with I.S. 813 and the Domestic Water Treatment Association’s (DWTA) code of practice.

fig. 7

Hot water

outlet

3a.11 SHOWERS

If the appliance is intended for use with a shower, the shower must be thermostatically controlled and be suitable for use with a combination boiler.

3A.12 DECLARATION OF CONFORMITY

A Declaration of Conformity (as defined in I.S.

813) must be provided on completion of the installation A copy of the declaration must be given to the responsible person and also to the gas supplier if required.

fig. 8

C/H flow

valve

C/H return

valve

Gas

cock

Cold water inlet

stopcock/filling

valve

Filling loop

Safety valve outlet

Default screws position of fixing jig: No. 3

Page 12

SECTION 4 INSTALLATION

4.1 DELIVERY

Due to the weight of the appliance it may be necessary for two people to lift and attach the appliance to its mounting. The appliance is contained within a heavy-duty cardboard carton. Lay the carton on the floor with the writing the correct way up.

4.2 CONTENTS

Contained within the carton is:

• The boiler

• The wall bracket & fixing jig

• Template

• An accessories pack containing appliance

service connections and washers

• The instruction pack containing the installation & servicing instructions, user instructions, guarantee registration card, and a 3-amp fuse.

4.3 UNPACKING

At the top of the carton pull both sides open – do not use a knife – unfold the rest of the carton from around the appliance, carefully remove all protective packaging from the appliance, and lay the accessories etc. to one side. Protective gloves should be used to lift the appliance, the appliance back-frame should be used for lifting points.

4.4 PREPARATION FOR MOUNTING THE APPLIANCE

The appliance should be mounted on a smooth, vertical, non-combustible surface, which must be capable of supporting the full weight of the appliance. Care should be exercised when determining the position of the appliance with respect to hidden obstructions such as pipes, cables, etc.

When the position of the appliance has been decided – using the template supplied – carefully mark the position of the wall-mounting bracket (see fig. 8) and flue-hole (if applicable). If you intend to run the pipe-work vertically behind the boiler, move the screws on the fixing jig from the default position (No. 3) to position No. 5. You will also require a spacer kit, part No. 435 (see 4.6).

horizontal plane (see 2.9). A reduction must also be made to the maximum length (see table below) when additional bends are used.

Reduction for additional bends Bend Reduction in maximum flue length for

each bend 45º bend 0.5 metre 90º bend 1.0 metre

Horizontal flue terminals and accessories

Part No. Description Length

520 Horizontal flue kit 900mm 521 Telescopic flue kit 350/530mm 522 Plume management kit 1370mm 523 90-degree bend N/A 524 45-degree bends (pair) N/A 525 500mm extension 500mm 526 1000mm extension 1000mm 527 2000m extension 2000mm 528 Telescopic extension 350/730mm 529 Wall bracket pack (5) 208mm

Using the template provided, mark and drill a 115mm hole for the passage of the flue pipe. The hole should be drilled to ensure any condense fluid that forms, is allowed to drain back to the appliance (see fig. 9A).

The fixing holes for the wall-mounting bracket/ fixing jig should now be drilled and plugged, an appropriate type and quantity of fixing should be used to ensure that the bracket is mounted securely. Once the bracket has been secured to the wall, mount the appliance onto the bracket.

4.5 FITTING THE FLUE

The top flue outlet permits both horizontal and vertical flue applications to be considered, alternatively, the Vokera twin flue system can be utilised if longer flue runs are required.

4.5.1 CONCENTRIC HORIZONTAL FLUE

(For concentric vertical flue, see 4.5.2) (For twin flue applications, see 4.5.3) The appliance can be used with either the Vokera condensing 60/100mm concentric flue system or the optional 80/125mm concentric flue system.

NOTE

These instructions relate only to the Vokera condensing 60/100mm concentric flue system. For specific details on the installation of the 80/ 125mm concentric flue system please refer to the instructions supplied.

The appliance flue outlet elbow can be rotated through 360º on its vertical axis. In addition the flue may be extended from the outlet elbow in the

Fig. 9

Page 13

FITTING THE HORIZONTAL FLUE KIT

Carefully measure the distance from the centre of the appliance flue outlet to the edge of the finished outside wall (dimension X). Add 65mm to dimension X to give you Dimension Y (see fig 9A). Measure dimension Y from the terminal end of the concentric flue pipe and cut off the excess ensuring any burrs are removed. Pass the concentric flue pipe through the previously drilled hole. Fit the flue bend to the boiler flue outlet and insert the concentric flue pipe into the flue bend ensuring the correct seal is made. Using the clamp, gasket, and screws supplied, secure the flue bend to the appliance flue spigot.

NOTE

Fit the internal (white) trim to the flue assembly prior to connecting the flue pipe to the bend. You must ensure that the entire flue system is properly supported and connected. Seal the flue assembly to the wall using cement or a suitable alternative that will provide satisfactory weatherproofing. The exterior trim can now be fitted.

“X”

Fig. 9A

30mm

“X” + 65mm = “Y”

“Y”

4.5.1.1 EXTENDING THE FLUE

Connect the bend – supplied with the terminal kit – to the top of the boiler using clamp (supplied) see fig. 9. The additional bends & extensions have push-fit connections, care should be taken to ensure that the correct seal is made when assembling the flue system. Connect the required number of flue extensions or bends (up to the maximum equivalent flue length) to the flue terminal (see fig. 9 & 10).

The flue system should have a minimum of 1º; maximum of 3º rise from the boiler to outside, to ensure any condense fluid that forms, is allowed to drain back to the appliance.

NOTE

When cutting an extension to the required length, you must ensure that the excess is cut from the plain end of the extension (see fig. 9 & 10). Remove any burrs, and check that all seals are located properly.

You must ensure that the entire flue system is properly supported and connected.

Seal the flue assembly to the wall using cement or a suitable alternative that will provide satisfactory weatherproofing. The interior and exterior trim can now be fitted.

1-3 degree

Fig. 10

4.5.2 CONCENTRIC VERTICAL FLUE

The appliance can be used with either the Vokera condensing 60/100mm concentric flue system or the optional 80/125mm concentric flue system. NOTE These instructions relate only to the Vokera condensing 60/100mm concentric flue system. For specific details on the installation of the 80/ 125mm concentric flue system please refer to the instructions supplied. The vertical flue terminal can be connected directly to the appliance flue outlet. Alternatively, an extension or bend can be connected to the appliance flue outlet if desired (see 4.4.2), however if additional bends are fitted, a reduction must be made to the maximum flue length (see table below).

Reduction for bends Bend Reduction in maximum flue length for each

bend 45º bend 0.5 metre 90º bend 1.0 metre

Vertical flue terminal and accessories Part No. Description Length 530 Vertical flue terminal 1000mm 531 Pitched roof flashing plate N/A 532 Flat roof flashing plate N/A 523 90-degree bend N/A 524 45-degree bends (pair) N/A 525 500mm extension 500mm 526 1000mm extension 1000mm 527 2000mm extension 2000mm 528 Telescopic extension 350/730mm 529 Wall bracket pack (5) 208mm

Using the dimensions given in fig. 9 as a reference, mark and cut a 115mm hole in the ceiling and/or roof.

Page 14

“X”

28/32/36 HE = 218 mm

12/15/20HE = 202mm 25/30/35HE = 218mm

Fig. 11

Fit the appropriate flashing plate to the roof and insert the vertical flue terminal through the flashing plate from the outside, ensuring that the collar on the flue terminal fits over the flashing. The fixing holes for the wall-mounting bracket/ fixing jig should now be drilled and plugged, an appropriate type and quantity of fixing should be used to ensure that the bracket is mounted securely. Once the bracket has been secured to the wall, mount the appliance onto the bracket.

IMPORTANT

The vertical flue terminal is 1.0 metre in length and cannot be cut; therefore it may be necessary to adjust the height of the appliance to suit or use a suitable extension.

Connect the vertical flue assembly to the boiler flue spigot using the 100mm clip, gasket, & screws (supplied), ensuring the correct seal is made. The flue support bracket (supplied with the vertical flue kit) can now be fitted.

If the vertical flue requires extension/s or additional bend/s, connect the required number of flue extensions or bends (up to the maximum equivalent flue length) between the boiler and vertical flue assembly (see fig. 10).

4.5.3 TWIN FLUE SYSTEM

The Vokera twin flue system enables greater flue distances to be achieved (see 4.4.2) than that of a concentric flue system. It can be used for horizontal or vertical applications, however the twin flue system must be converted to the dedicated concentric flue kit for termination. It is essential that the installation of the twin flue system be carried out in strict accordance with these instructions.

GUIDANCE NOTES ON TWIN FLUE INSTALLATION

• The flue must have a have a minimum 1º; maximum 3º (1º = 17mm per 1000mm) fall back to the appliance to allow any condensate that may form in the flue system to drain via the condensate drain. Consideration must also be given to the fact that there is the possibility of a small amount of condensate dripping from the terminal.

• Ensure that the entire flue system is adequately supported, use at least one bracket for each extension.

• The entire flue system must be adequately insulated to maintain heat within the flue system thereby reducing the possibility of condensate production.

• As the exhaust outlet pipe can reach very high temperatures it must be protected to prevent persons touching the hot surface.

• The condensate drain pipe must be connected in accordance with building regulations

Reduction for bends Bend Reduction in maximum flue length for

each bend 45º bend 1.0 metre 90º bend 1.0 metre

Twin flue accessories Part No. Description Length

0225805 Horizontal flue terminal 1.0 metre 0225810 Vertical flue terminal 1.0 metre 359 Twin adapter kit N/A 531 Pitched roof flashing plate N/A 532 Flat roof flashing plate N/A 0225815 Condensate drain kit N/A 0225820 0.25m extension (pair) 250mm 0225825 0.5m extension (pair) 500mm 0225830 1.0m extension (pair) 1000mm 0225835 2.0m extension (pair) 2000mm 0225840 45º bend (pair) N/A 0225845 90º bend (pair) N/A 0225850 Twin bracket (5) N/A 0225855 Single bracket (5) N/A

Ensure that any horizontal sections of the flue system have a minimum 1º; maximum 3º fall back to the boiler (1º = 17mm per 1000mm)

NOTE

When cutting an extension to the required length, you must ensure that the excess is cut from the plain end of the extension (see fig. 8). Remove any burrs, and check that any seals are located properly.

You must ensure that the entire flue system is properly supported and connected.

MOUNTING THE BOILER The fixing holes for the wall-mounting bracket should now be drilled and plugged, an appropriate type and quantity of fixing should be used to ensure that the bracket is mounted securely. Once the bracket has been secured to the wall, mount the appliance onto the bracket.

4.5.3.1 INSTALLATION OF TWIN ADAPTOR KIT (fig. 12

& 13)

• Insert the exhaust connection manifold (A) onto the appliance flue outlet.

• Remove the blanking plate (located to the right of the appliance flue outlet) and – using the same

Page 15

screws – install the air inlet plate (B).

• Using the hole in the exhaust connection manifold as a guide, drill a 3mm hole in the appliance flue spigot and secure the exhaust manifold connection to the flue spigot using the screw provided (C).

• Using the two holes in the air inlet plate as a guide, drill a 3mm hole in each and secure the air inlet pipe/bend using the screws provided.

The twin flue pipes extensions and accessories can now be installed by pushing together (the plain end of each extension or bend should be pushed approximately 50mm into the female socket of the previous piece).

connects to the exhaust connection on the concentric to twin converter.

If necessary cut the plain ends (male) of the twin flue pipes to allow connection to the concentric to twin converter.

NOTE; before cutting twin flue pipes ensure allowances have been made for connection onto the previous piece and onto the concentric to twin converter. The last twin Flue pipes must be pushed 50mm onto the male spigots of the concentric to twin converter.

NOTE;

Seal the flue terminal assembly to the wall using cement or a suitable alternative that will provide satisfactory weatherproofing. The interior and exterior trim can now be fitted.

Fig. 12

Fig. 13

4.5.3.2 HORIZONTAL TERMINATION (See fig. 14)

The twin flue system must be converted to the

dedicated concentric flue kit for termination.

• The horizontal terminal is supplied with a built-

in converter box and cannot be shortened.

• A 130mm hole is required for the passage of the

concentric terminal through the wall.

• The air inlet pipe must always be level with or

below, that of the exhaust pipe.

4.5.3.3 VERTICAL TERMINATION (See fig. 15)

The twin flue system must be converted to the

dedicated concentric flue kit for termination.

• The vertical terminal is supplied with a built-in

converter box and cannot be shortened.

• A 130mm hole is required for the passage of the

concentric terminal through the ceiling and/or roof.

Depending on site conditions it may be preferable

to install the terminal assembly prior to fitting the twin flue pipes.

Fit the appropriate flashing plate to the roof and

insert the vertical flue terminal through the flashing plate from the outside, ensuring that the collar on the flue terminal fits over the flashing.

Push-fit the twin flue pipes onto the concentric to

twin converter ensuring that the exhaust pipe connects to the exhaust connection on the concentric to twin converter.

If necessary cut the plain ends (male) of the twin

flue pipes to allow connection to the concentric to twin converter.

NOTE

• Before cutting twin flue pipes ensure allowances

have been made for connection onto the previous piece and onto the concentric to twin converter. The last twin flue pipes must be pushed 50mm onto the male spigots of the concentric to twin converter.

• You must ensure that the entire flue system is

properly supported and connected.

• Ensure that any horizontal sections of pipe have

a 1º fall towards the appliance (17mm per 1000mm).

Depending on site conditions it may be preferable to install the terminal assembly prior to fitting the twin flue pipes.

Mark and drill a level 130mm hole for the passage of the horizontal flue terminal. Insert the terminal assembly into the flue hole.

Push-fit the twin flue pipes onto the concentric to twin converter box ensuring that the exhaust pipe

Page 16

Fig. 14

The appliance is supplied with a fixing jig that includes service valves (fig. 14). The service valves are of the compression type. The accessories pack contains sealing washers etc, for use with the service valves.

When connecting pipe work to the valves, tighten the compression end first then insert the sealing washers before tightening the valve to the appliance.

NOTE

It will be necessary to hold the valve with one

spanner whilst tightening with another.

4.6.1 GAS (fig. 16)

The appliance is supplied with a 15mm service valve, connect a 15mm pipe to the inlet of the valve and tighten both nuts.

NOTE

It will be necessary to calculate the diameter of the gas supply pipe to ensure the appliance has an adequate supply of gas.

4.6.2 FLOW & RETURN (fig. 16)

The appliance is supplied with 22mm service valves for the flow and return connections, connect a 22mm pipe to the inlet of each valve and tighten both nuts.

NOTE

Depending on system requirements, it may necessary to increase the size of the flow & return pipe work after the service valve connections.

4.6.3 COLD WATER INLET (Fig. 16)

The appliance is supplied with a 15mm combined stopcock and double check-valve, connect a 15mm pipe to the inlet of the stopcock and tighten both nuts.

4.6.4 HOT WATER OUTLET (Fig. 16)

The appliance is supplied with a 15mm outlet connection, connect a 15mm pipe to the outlet connection and tighten both nuts.

Hot water

outlet

Fig. 15

4.6 CONNECTING THE GAS AND WATER

IMPORTANT - REAR SPACER KIT If you intend to run the pipe-work vertically behind the appliance, it will be necessary to use the rear spacer kit (part code 435). It will also be necessary to adjust the pitch of the fixing jig to compensate for the increase in the depth of the appliance.

Fig. 16

C/H flow

valve

C/H return

valve

Gas

cock

Cold water inlet

stopcock/filling

valve

Filling loop

Safety valve

outlet

Page 17

4.6.5 SAFETY VALVE (fig. 16)

Connect the safety valve connection pipe to the safety valve outlet. Connect a discharge pipe to the other end of the safety valve connection pipe and tighten. The discharge pipe must have a continuous fall away from the appliance to outside and allow any water to drain away thereby eliminating the possibility of freezing. The discharge pipe must terminate in a position where any water – possibly boiling – discharges safely without causing damage or injury, but is still visible.

4.6.5 CONDENSE PIPE

During normal operation the boiler produces condense which is collected in a trap located in the lower part of the boiler. A flexible pipe (condense outlet pipe) is connected to the outlet of the trap. The flexible pipe must be connected to a plastic waste pipe only. The plastic waste pipe must have a minimum of a 3º fall towards the drain. Any external run of pipe should be insulated to prevent the risk of freezing.

CONNECTING THE CONDENSATE OUTLET

Gently pull the condense outlet pipe down from its location inside the boiler until approximately 100mm protrudes from the underside of the boiler. Connect a suitable plastic (not copper) pipe (no less than 20mm diameter) to the outlet pipe and ensure it discharges in accordance with building regulations or other rules in force.

Fig. 17

Optional devices

(24V) terminal block

Mains (230V) terminal block

4.7 ELECTRICAL CONNECTIONS

The electrical supply must be as specified in section 3/3A. A qualified electrician should connect the electrical supply to the appliance. If controls – external to the appliance – are required, a competent person must undertake the design of any external electrical circuits, please refer to section 8 for detailed instructions. ANY EXTERNAL CONTROL OR WIRING MUST BE SERVED FROM THE SAME ISOLATOR AS THAT OF THE APPLIANCE. The supply cable from the isolator to the appliance must be 3-core flexible sized 0.75mm to BS 6500 or equivalent. Wiring to the appliance must be rated for operation in contact with surfaces up to 90ºC.

4.7.1 CASING REMOVAL Fig. 17

To gain internal access to the appliance you must first remove the casing, proceed as outlined below:

• Remove the 4 screws (B) located on the underside of the casing.

• Lift the casing upward to disengage it from the top locating hooks and then remove.

• Store the casing and screws (B) safely until required. Re-fit in the reverse order.

4.7.2 APPLIANCE TERMINAL BLOCK

The appliance terminal block is located on the rear of the control fascia. Remove the casing as described in 4.7.1. Gently pull the control panel forwards and down. Locate the terminal block cover (see fig. 18).

NOTE

The appliance comes with a factory fitted link (‘TA’) to allow basic operation of the boiler via the mode selector switch. If it is anticipated that external controls will be required please refer to the wiring diagrams in section 8 for more detailed information.

Fig. 18

Fig. 19

4.7.3 CONNECTING THE MAINS (230V) INPUT (see FIG. 19).

Unhook and remove the terminal block cover (230V). Pass the cable through the cable anchorage point. Connect the supply cable wires (LIVE, NEUTRAL, & EARTH) to their corresponding terminals (L, N, & E) on the appliance – high voltage – terminal block. When connecting the EARTH wire, ensure that it’s left slightly longer that the others, this will prevent strain on the EARTH wire should the cable become taut. Do not remove the link wire unless additional external controls are to be fitted (see section 8). The securing screw on the cable anchorage should now be tightened. This must be done before the terminal block cover is re-fitted in its position.

NOTE

It is the installer’s responsibility to ensure that the appliance is properly Earthed. Vokera Ltd. cannot be held responsible for any damages or injuries caused as a result of incorrect Earth wiring.

Page 18

SECTION 5 COMMISSIONING

5.1 GAS SUPPLY INSTALLATION

Inspect the entire installation including the gas meter, test for soundness and purge. Refer to BS 6891 (I.S. 813 in ROI) for specific instruction.

5.2 THE HEATING SYSTEM

The appliance contains components that may become damaged or rendered inoperable by oils and/or debris that are residual from the installation of the system, consequently it is essential that the system be flushed in accordance with the following instructions.

5.3 INITIAL FILLING OF THE SYSTEM

Ensure both flow and return service valves are open, remove appliance casing as described in

4.7.1, identify the automatic air release valves (AAV) and loosen the dust cap/s by turning the cap anti-clockwise one full turn.

Ensure all manual air release valves located on the heating system are closed. Connect the filling loop as shown in fig. 5, slowly proceed to fill the system by firstly opening the inlet valve connected to the flow pipe, and then turning the lever on the fill valve, to the open position. As water enters the system the pressure gauge will begin to rise. Once the gauge has reached 1 BAR close both valves and begin venting all manual air release valves, starting at the lowest first. It may be necessary to go back and top-up the pressure until the entire system has been filled. Inspect the system for water soundness, rectifying any leaks.

5.3.1 MANUAL AIR RELEASE (Fig. 20)

When the boiler has been filled for the first time or the system has been drained and refilled, it will be necessary to release any air that may have become trapped within the appliance heat exchanger. Slacken the bleed screw until water is released and then close.

IMPORTANT, THERE ARE NO OTHER MANUAL AIR RELEASE VALVES LOCATED ON THE APPLIANCE.

5.4 INITIAL FLUSHING OF THE SYSTEM

The whole of the heating system must be flushed both cold and hot as detailed in 5.8. Open all radiator or heating valves and the appliance flow & return service valve. Drain the boiler and system from the lowest points. Open the drain valve full bore to remove any installation debris from the boiler prior to lighting. Refill the boiler and heating system as described in 5.3.

5.5 PRE-OPERATION CHECKS

Before attempting the initial lighting of the appliance, the following checks must be carried out:

• Ensure all gas service valves from the meter to the appliance are open and the supply pipe has been properly purged;

• Ensure the proper electrical checks have been carried out, (see 7.8) particularly continuity, polarity, and resistance to earth;

• Ensure the 3 AMP fuse – supplied with the appliance – has been fitted;

• Ensure the system has been filled, vented, and the pressure set to 1 BAR;

• Ensure the flue system has been fitted properly and in accordance with the instructions;

• Ensure all appliance service valves are open.

5.6 INITIAL LIGHTING

Ensure the electrical supply to the appliance is switched on. Ensure any external controls are switched to an ‘ON’ position and are calling for heat. Move the selector switch to the ON position, the appliance will now operate as described in 1.2. Should the appliance fail to ignite, refer to 5.6 and/ or section 7 (mode of operation, parameter setting, & faultfinding).

5.7 CHECKING GAS PRESSURE AND COMBUSTION ANALYSIS

The appliance is factory set and requires no additional adjustment once installed. However to satisfy the requirements of GSIUR 26/9 (I.S. 813 ROI), it will be necessary to gas rate the appliance using the gas meter that serves the appliance.

Fig. 20

If the installation does not include a gas meter (for example LPG) and there are no means by which to calculate the gas rate, then a combustion analysis test must be carried out in accordance with BS 7967 (UK) to ensure the appliance is left working safely and correctly.

Additionally, if the gas valve has been adjusted, replaced, or the appliance has been converted for use with another gas type, then it becomes necessary to carry out a combustion analysis/ check to ensure that correct combustion is occurring.

If there are no means to gas rate the appliance and/or carry out a combustion analysis check, then it will not be possible to complete the commissioning procedure.

Details on how to carry out the combustion analysis can be found in section 7.

Page 19

IMPORTANT

It’s imperative that a sufficient dynamic – gas – pressure is maintained at all times. Should the dynamic gas pressure fall below an acceptable level, the appliance may malfunction or sustain damage.

5.8 FINAL FLUSHING OF THE HEATING SYSTEM

The system shall be flushed in accordance with BS 7593 (I.S. 813 ROI). Should a cleanser be used, it must be suitable for Aluminium heat exchangers. It shall be from a reputable manufacturer and shall be administered in strict accordance with the manufacturers’ instructions and the DWTA code of practice.

5.8.1 INHIBITORS

See Section 3 “General Requirements”.

5.9 SETTING THE FLOW OUTLET TEMPERATURE

The flow outlet temperature can be adjusted between 40 °C - 80 °C for standard CH system and between 20 °C - 45 °C for under-floor systems by using the Heating thermostat knob (see fig.1).

5.9.1 SETTING THE DHW OUTLET TEMPERATURE

The DHW outlet temperature can be adjusted between 35 °C - 60 °C via the DHW thermostat knob (see fig.1).

5.10 SETTING THE SYSTEM DESIGN PRESSURE

The design pressure should be a minimum of 0.5 BAR and a maximum of 1.5 BAR. The actual reading should ideally be 1 BAR plus the equivalent height in metres (0.1 BAR = 1 metre) to the highest point in the system above the base of the appliance (up to the maximum of 1.5 BAR total). N.B. The safety valve is set to lift at 3 BAR/30 metres/45 psig. To lower the system pressure to the required value, drain off some water from the appliance drain valve until the required figure registers on the pressure gauge (see fig. 1).

5.11 REGULATING THE CENTRAL HEATING SYSTEM

Fully open all radiator and circuit valves and run the appliance for both heating and hot water until heated water is circulating. If conditions are warm remove any thermostatic heads. Adjust radiator return valves and any branch circuit return valves until the individual return temperatures are correct and are approximately equal.

5.11.1 REGULATING THE DHW FLOW-RATE

The appliance is fitted with a flow rate restrictor that limits the maximum flow rate that can be drawn through the appliance. The restrictor eliminates the need to manually adjust the DHW flow rate. However if it is felt necessary to further increase or decrease the available flow rate, spare restrictors are included in the accessory pack. The spare flow rate restrictors can be fitted to either increase or decrease the maximum flow rate. The tables overleaf denote the size of restrictor fitted and the spare restrictors supplied in the accessory pack. Each restrictor is colour-coded to enable identification.

5.11.2 CHANGING THE FLOW-RATE RESTRICTOR

Refer to 6.27 for detailed instruction on changing the flow restrictor.

Unica 28HE

9-litres 10-litres11-litres (Orange) (Blue) (Beige) Spare Fitted Spare

Unica 32HE

11-litres 12-litres13-litres (Beige) (Red) (Olive) Spare Fitted Spare

Unica 36HE

13-litres 14-litres15-litres (Olive) Spare Fitted spare

5.12 FINAL CHECKS

• ENSURE ALL TEST NIPPLES ON THE APPLIANCE GAS VALVE ARE TIGHT AND CHECKED FOR SOUNDNESS.

• ENSURE THE APPLIANCE FLUE SYSTEM IS FITTED CORRECTLY AND IS PROPERLY SECURED.

• ENSURE ALL PIPE WORK IS RECHECKED FOR SOUNDNESS.

• RE-FIT APPLIANCE CASING.

• COMPLETE BENCHMARK CHECKLIST.

FOR UK ONLY

Complete details of the boiler, controls, installation and commissioning in the Benchmark checklist at the back of this book. It is important that the Benchmark checklist is correctly completed and handed to the user. Failure to install and commission the appliance to the manufacturers instructions may invalidate the warranty.

5.13 INSTRUCTING THE USER

Hand over all documentation supplied with this appliance – including these instructions – and explain the importance of keeping them in a safe place. Explain to the user how to isolate the appliance from the gas, water and electricity supplies, and the locations of all drain points. Show the user how to operate the appliance and any associated controls correctly. Show the user the location of the filling valve and how to top-up the system pressure correctly and show the location of all manual air release points.

Explain to the user how to turn off the appliance for both long and short periods and advise on the necessary precautions to prevent frost damage. Explain to the user that for continued safe and efficient operation, the appliance must be serviced annually by a competent person.

IMPORTANT

To validate the appliance warranty, it’s necessary to register the appliance details with us. The warranty can be registered in several ways:

• By completing the warranty registration card and posting to us using the envelope supplied

• Online at: vokera.co.uk

• For UK residents by calling: 0870 607

0281

• For ROI residents by calling: 1850

221121.

Page 20

SECTION 6 SERVICING INSTRUCTIONS

6.1 GENERAL

To ensure the continued safe and efficient operation of the appliance, it is recommended that it is checked and serviced at regular intervals. To ensure correct and safe operation of the appliance, it is essential that any worn or failed component be replaced only with a genuine Vokera spare part. It should be remembered that although certain generic components may look similar, they will be specific to an individual appliance or product range. Use of non-genuine Vokera spare parts could invalidate your warranty and may pose a potential safety hazard. The frequency of servicing will depend upon the particular installation conditions, but in general, once per year should be sufficient. It is the law that any servicing work is carried out by competent person such as a Vokera engineer, an approved service agent, British Gas,

CORGI registered personnel or other suitably qualified personnel. The following instructions apply to the appliance and its controls, but it should be remembered that the central heating and the domestic hot water systems would also require attention from time to time.

6.2 ROUTINE ANNUAL SERVICING

• Check the operation of the appliance and ensure it functions as described in section 7.

• Compare the performance of the appliance with its design specification. The cause of any noticeable deterioration should be identified and rectified without delay.

• Thoroughly inspect the appliance for signs of damage or deterioration especially the flue system and the electrical apparatus.

• Check and adjust – if necessary – all burner pressure settings (see 7.4).

• Check and adjust – if necessary – the system design pressure (see 5.10).

• Carry out an analysis of the flue gases (see

7.5), and visually check the condition of the entire flue assembly.

• Compare the results with the appliance design specification. Any deterioration in performance must be identified and rectified without delay.

• Check that the burner and main heat exchanger are clean and free from any debris or obstruction.

• Check and clean – if necessary – the condense trap to ensure correct operation.

content from the appliance via the drain valve. Ensure some water absorbent cloths are available to catch any residual water that may drip from the appliance or removed component. Undertake a complete commissioning check as detailed in section 5, after replacing any component.

ALWAYS TEST FOR GAS SOUNDNESS IF ANY GAS CARRYING COMPONENTS HAVE BEEN REMOVED OR DISTURBED.

6.4.1 AIR BOX FRONT COVER REMOVAL (fig. 21)

Locate the two clips and remove air box front cover. If it’s necessary to remove the air box side cover, locate and remove the 4 securing screws.

clips

fig. 21

6.5 PUMP ASSEMBLY (fig. 22)

Carry out component removal procedure as described in 6.4. Disconnect the flow pipe (B) from the combustion chamber connection (only 32/36 HE), slacken the pipe at the hydraulic assembly and swing/rotate clear of the pump assembly. Disconnect and remove the pump outlet pipe (C) from the pump assembly/combustion chamber connection.

6.3 REPLACEMENT OF COMPONENTS

Although it is anticipated that this appliance will give years of reliable, trouble free service, the life span of components will be determined by factors such as operating conditions and usage. Should the appliance develop a fault, the fault finding section will assist in determining which component is malfunctioning.

6.4 COMPONENT REMOVAL PROCEDURE

To remove a component, access to the interior of the appliance is essential. Isolate the appliance from the electrical supply and remove the fuse. And when necessary, close all service valves on the appliance, remove the appliance casing as described in section 4.7.1 and drain the water

fig. 22

Remove the expansion pipe locking pin (D) from the top of the pump assembly and withdraw the flexible pipe. Locate and remove the pressure gauge securing pin ( pressure gauge from the pump assembly.

) and disconnect the

Disconnect the electrical wiring from the pump’s electrical connection point (E). Locate and remove the 2 securing screws (A) at the rear of the pump assembly. Remove locking pin (F) from pump base and lift pump assembly clear of the hydraulic manifold. The pump assembly can now be removed from the appliance. Replace carefully in the reverse order.

Page 21

6.6 SAFETY VALVE (fig. 23)

Carry out component removal procedure as described in 6.4. Disconnect the outlet pipe (A) from the safety valve, remove safety valve locking pin (B) from the hydraulic manifold. Replace in the reverse order.

fig. 23

6.7 LOWER AUTOMATIC AIR RELEASE VALVE (fig. 22)

Carry out component removal procedure as described in 6.4. Remove the expansion pipe locking pin (D) from the pump assembly and remove the expansion pipe. Locate and remove the AAV locking pin (G) from the pump assembly and remove the AAV assembly (H). Replace in the reverse order.

6.11 PRINTED CIRCUIT BOARD (fig. 25)

Carry out component removal procedure as described in 6.4. Pull the control fascia forward and lower it. Push the clips (A) which secure the PCB cover, remove cover, after carefully taking note of all wiring connections and jumper tag configuration. Unhook and remove connection block (B). Disconnect all wiring from the PCB, locate and remove the PCB securing screws, remove the required PCB. Replace in the reverse order ensuring that the position of the 3 control knobs are correctly aligned with the respective potentiometers on the PCB.

Ensure that the correct jumper tag configuration has been respected. It will be necessary to check the functioning of the PCB is set for the correct boiler type/application.

Fig. 25

6.7.1 TOP AUTOMATIC AIR RELEASE VALVE (fig.

24)

Carry out component removal procedure as

described in 6.4.

Remove the drain pipe (A). Unscrew the top AAV (B). Replace in the reverse order. Loctite or similar should be used as a thread sealant for the AAV.

Fig. 24

6.8 WATER PRESSURE SWITCH (fig. 23)

Carry out component removal procedure as described in 6.4. Locate and remove the locking pin (C) from the water pressure switch. Remove the wiring. Carefully withdraw the switch. Replace in the reverse order.

6.9 PRIMARY THERMISTOR (fig. 1)

Carry out component removal procedure as described in 6.4. Unclip and remove the air chamber front cover. Unclip the primary thermistor from the flow outlet pipe. Disconnect thermistor electrical plug. Replace in the reverse order.

6.10 RETURN THERMISTOR (fig. 1)

Carry out component removal procedure as described in 6.4. Unclip and remove the air chamber front cover. Unclip the return thermistor from the return inlet pipe. Disconnect thermistor electrical plug. Replace in the reverse order.

6.12 GAS VALVE (fig. 26)

Carry out component removal procedure as described in 6.4. The gas valve must be changed as complete unit. Disconnect the electrical plug and leads from the gas valve, slacken and unscrew gas valve inlet and outlet connections. Please note, the sealing washers (B) must be discarded and replaced with new sealing washers. Disconnect the compensation pipe (C). Locate and remove gas valve retaining screws (D) on the underside of the boiler if required, the gas valve can now be removed. Replace in the reverse order. Check and adjust burner pressure settings.

WARNING, A GAS SOUNDNESS CHECK MUST BE CARRIED OUT.

fig. 26

6.12.1 INJECTOR (fig. 26)

Carry out component removal procedure as described in 6.4. Unscrew and remove gas pipe connections (A & E). Locate and remove the injector (F) inside the pipe. Replace in the reverse order. Check and adjust burner pressure settings.

WARNING, A GAS SOUNDNESS CHECK MUST BE CARRIED OUT.

Page 22

6.13 ELECTRODES & CONDENSE SENSOR (fig. 27)

Carry out component removal procedure as described in 6.4. Unclip and remove the air chamber front and RH side covers. Disconnect the electrode leads and ancillary wiring from their respective connectors. Remove the retaining screws (A) for electrode and remove. Remove the retaining nut

(D). Disconnect the electrode leads and ancillary

wiring from their respective connectors. Remove the retaining screws (A, fig. 29) for sensing electrode and remove. Remove the retaining nut (C, fig. 29) for condense sensor (D, fig. 29) and remove. Gently ease the fan assembly out of its location. Once the assembly has been removed, the burner (E) can be withdrawn from the heat engine. Ensure the seal (F) is in good condition, taking care to ensure it is replaced correctly. Replace in the reverse order.

fig. 27

6.14 FLUE FAN & MIXER (fig. 28)

Carry out component removal procedure as described in 6.4. Unclip and remove the air chamber front and the RH side covers. Slacken the gas pipe (A) at the air box connection and swing/rotate away from the fan assembly. Locate and remove the sense electrode. To remove the mixer (B) locate and remove the three screws (C). To remove the fan (D), disconnect the electrical connections attached to the fan, locate and remove the four screws (E). Gently ease the fan from its location. Replace in the reverse order. Ensure all seals are in good condition, taking care to ensure they are replaced correctly.

fig. 29

fig. 30

fig. 28

6.15 BURNER (fig. 30)

6.16 MAIN HEAT EXCHANGER (fig. 30 & 31)

Carry out component removal procedure as described in 6.4. Unclip and remove the three air chamber covers (front, LH, RH sides). Disconnect all the wiring connections. Fig. 29: Slacken the gas pipe (A) at the air box connection and swing/ rotate of the fan assembly. Disconnect the flow (B), return (C) and condense connections on the heat exchanger. Locate and remove the 4-screws that secure the heat exchanger to the combustion chamber (D). Move the heat exchanger to the right and disconnect it from the flue collector (E). The heat exchanger can now be lifted up and withdrawn from the appliance.

fig. 31

Page 23

Fig. 31: To remove the fan burner assembly (A) locate and remove the 3 external nuts (B). Replace in the reverse order. Ensure all seals are in good condition, taking care to ensure they are replaced correctly.

6.17 AUTOMATIC BY-PASS & DHW NON-RETURN VALVE (fig. 32)

Carry out component removal procedure as described in 6.4. Remove the locking pin (A) that secures the cover (B) to the hydraulic manifold. Using a hooked piece of wire, carefully withdraw the by-pass cartridge (C) and/or DHW non-return cartridge (D). Ensure all seals are in good condition, taking care to ensure they are replaced correctly. Replace in the reverse order ensuring the cartridge is facing the correct way.

fig. 34

Fig. 32

6.18 EXPANSION VESSEL (fig. 1)

Should the removal and replacement of the expansion vessel be deemed impractical, an external expansion vessel may be fitted to the return pipe as close to the appliance as possible.

6.18.1 EX PANSION VESSEL REMOVAL (with sufficient clearance above, fig. 33)

Carry out component removal procedure as described in 6.4. Disconnect the flue from the appliance. Disconnect the expansion vessel from the flexible expansion pipe. Disconnect the flexible expansion pipe from the vessel. Unscrew the nut that secures the vessel to the lower frame. Locate and remove the 6 screws (A) that secure the vessel top holding plate (B), remove the plate. The expansion vessel can now be removed. Replace in the reverse order. Ensure all seals are in good condition, taking care to ensure they are replaced correctly.

6.19 CONDENSE TRAP REMOVAL (fig. 34)

Carry out component removal procedure as described in 6.4. Disconnect the 2 upper rubbers condense pipe (A). Remove the pin (B) that secures the trap to the air box plate. Disconnect the lower rubber condense pipe (C) from the condense trap. Carefully remove the condense trap. Replace in the reverse order.

6.20 FLUE COLLECTOR REMOVAL (fig. 35)

Carry out component removal procedure as described in 6.4. Unclip and remove the air chamber front and left side covers. Locate and remove the screw (A) that secures the flue gas analysis test point cover (B). Gently pull down and to the left and ease the flue collector from its location. Replace in the reverse order.

fig. 33

fig. 35

Page 24

6.20.1 DHW FLOW RESTRICTOR (Fig. 35A)

Carry out the component removal procedure as

described in 6.4.

Disconnect the cold water inlet pipe at the DHW flow switch (A). Using a small screwdriver, gently ease the flow restrictor (B) from its seating. Replace in the reverse order. Ensure all seals are in good condition, taking care to ensure they are replaced correctly.

fig. 35A

6.20.4 DHW THERMISTOR (Fig. 35B)

Carry out component removal procedure as

described in 6.4.

Locate and remove the thermistor locking pin (H). Gently ease the thermistor assembly (I) from the hydraulic manifold. Replace in the reverse order.

6.20.5 DIVERTOR VALVE ASSEMBLY (Fig. 35C)

Carry out component removal procedure as described in 6.4. Remove the valve actuator as described in 6.20. Locate and remove the locking

pin (A) that secures the valve housing cover to the hydraulic manifold. Gently prise the valve assembly from the manifold. Replace in the reverse order ensuring that the seating assembly is inserted properly. Ensure all seals are in good con-

dition, taking care to ensure they are replaced correctly.

6.20.2 DHW FLOW SWITCH (Fig. 35A)

Carry out component removal procedure as

described in 6.4.

Remove the locking pin (C). Disconnect and remove the cold water inlet pipe from the DHW flow switch & DHW heat exchanger. Disconnect the wiring to the DHW flow switch. Slacken and unscrew the inlet connection (B, fig. 14). Unscrew the nut (D). Lift the DHW flow switch housing from its seating. If necessary remove the locking pin (E) from the DHW flow switch, taking care not to lose the float contained within the housing.

Replace in the reverse order ensuring that the housing is firmly inserted onto its seating. Ensure all seals are in good condition, taking care to ensure they are replaced correctly.

Fig. 35C

fig. 35B

6.20.3 VALVE ACTUATOR (Fig. 35B)

Carry out component removal procedure as described in 6.4.

Remove the locking pin (F) that secures the actuator (G) to the heating manifold. Disconnect the electrical plug from the actuator. Replace in the reverse order.

Page 25

SECTION 7 CHECKS, ADJUSTMENTS AND FAULT FINDING

7.1 CHECKING APPLIANCE OPERATION

When carrying out any repairs or servicing to the appliance, the relevant commissioning procedure must be undertaken to ensure the continued safe operation of the appliance. Particular attention should be made to ensure gas soundness, water soundness, and the electrical integrity of the appliance.

7.2 APPLIANCE MODES OF OPERATION

NOTE

There must be sufficient system water pressure (min. 0.5 bar) to ensure the water pressure switch is activated. If there is insufficient system pressure the pump and fan will be prevented from operating and the low-pressure fault code will be displayed.

The 2-digit display can show several different modes of operation:

Standby/OFF mode

Frost protection mode active

Combustion analysis mode active

Autostop function active

Normal heating request (example 60oC).

Normal DHW request (example 60oC).

7.2.1 SELECTOR SWITCH IN THE OFF/RESET POSITION

When the selector switch is in the OFF/RESET position, the following functions are active.

Active functions:

• Frost-protection system

• Pump & fan anti-block

7.2.1 ON-BOARD FUNCTIONS

• THERMOREGULATION: When an external

sensor is connected to the appliance, the electronic circuitry will automatically adjust the flow outlet temperature to suit local weather conditions in order to maintain comfort and efficiency. A specific operating curve that is most suited to the system type and geographical area can also be selected.

• OPENTHERM +: OT+ is a communication

protocol that enables the boiler to be linked or connected to other OT+ controls. These controls

have been designed to further increase fuel economy by ensuring the boiler remains in the modulation phase during any heating requests. This reduces the amount of ON/OFF periods and therefore increases fuel efficiency.

• AUTOSTOP: Further information on the AUTOSTOP function, can be obtained from your local Vokera Sales Representative.

• CO FUNCTION: The CO function when activated, will allow the appliance to run at maximum and minimum output whilst a combustion analysis check is being carried out. Whilst the CO function is active, all other functions are disabled (minimum power operating period, anti-cycle, set-point, etc). Once enabled, the CO function will remain active for a 15-minute period, or until the function is manually deactivated

• FROST-PROTECTION: this function is only active when there are no requests for heating or HW. If the temperature drops below 6°C, the boiler will operate on minimum power until the temperature of the primary thermistor reaches 35°C. Thereafter the pump & fan will over-run for 30-seconds.

• ANTI-CYCLE FUNCTION: The anti-cycle function ensures the burner remains switched off for at least 3-minutes after the set-point hysterisis (set-point + 5-deg).

• PUMP ANTI-BLOCK FUNCTION: when there has been no heating or HW request for 24-hours, the anti-block cycle is activated. The pump will be activated for a period of 30-seconds.

• ACTUATOR ANTI-BLOCK FUNCTION: when there has been no heating or HW request for 24hours, the anti-block cycle is activated. The divertor valve actuator will motor briefly to the heating position, and then back to the DHW position.

• DHW PRE-HEAT FUNCTION: When the mode selector switch is in the DHW pre-heat position, the appliance will light periodically to maintain the temperature of the DHW heat exchanger. When the DHW thermistor and the Primary thermistor fall below 35 the boiler will fire on minimum +25% power until the primary thermistor exceeds 55 the pump will over-run for a period of 30-seconds.

7.2.5 HEATING MODE

With the selector switch in the heating & hot water position and any additional controls (time clock, programmer, room thermostat, etc,) calling for heat, the appliance will operate in the heating mode. The pump and fan will be activated via the flow temperature sensor. When the fan is sensed to be operating correctly (tacho signal) , the ignition sequence commences. Ignition is sensed by the electronic circuit to ensure flame stability at the burner. Once successful ignition has been achieved, the electronic circuitry increases the gas rate to 75% for a period of 15 minutes. The speed of the fan and therefore the output of the boiler is determined by the temperature of the water sensed by the flow temperature sensor, consequently a high temperature at the flow sensor results in a lower fan speed. As the water

C and 55oC respectively,

C. Thereafter

Page 26

temperature increases, the temperature sensors – located on the flow pipe of the boiler – reduce the fan speed via the electronic circuitry. Depending on the load, either the water temperature will continue to rise until the set point is achieved or the water temperature will fall whereby fan speed will increase relative to the output required. When the boiler has reached the set point (+ hysterisis), the burner will switch off. The built-in anti-cycle device prevents the burner from re-lighting for approximately 3-minutes. When the temperature of the flow sensor falls below the set point (- hysterisis), the burner will re-light.

7.3.3 ABSOLUTE MIN FAN SPEED Locate the MIN trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table 7.3.6). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

7.3.4 IGNITION FAN SPEED

Locate the IGN trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table 7.3.6). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

NOTE

If the spark/sensing electrode does not sense ignition the appliance will re-attempt ignition a further 4-times then go to lockout. When the setpoint has been reached (the position of the heating temperature selector) as measured at the primary thermistor, the appliance will begin the modulation phase whereby the fan and gas valve will continuously modulate to maintain the set-point. If the temperature continues to rise and exceeds the set-point by 5°C (hysterisis), the burner will shut down. A new ignition sequence will be enabled when the 3- minute anti-cycle has been performed and the temperature at the primary thermistor has dropped 5°C (hysterisis) below the set-point.

7.2.5 DHW MODE

With the selector switch in either the hot water only or heating & hot water position, the appliance will operate in the hot water mode whenever a DHW outlet is opened. A flow rate exceeding 2litres per minute will activate the DHW flow switch whereupon the pump and fan will be activated via the flow temperature sensor. When the fan is sensed to be operating correctly (tacho signal), the ignition sequence commences. Ignition is sensed by the electronic circuitry to ensure flame stability at the burner. Once successful ignition has been achieved, the electronic circuit allows the gas rate to achieve the modulation value.

NOTES

When the request for heating and/or hot water has been satisfied, the appliance pump and fan may continue to circulate to dissipate any residual heat within the appliance.

7.3 APPLIANCE FAN SPEEDS

The appliance fan speeds require to be checked and/or adjusted prior to making any adjustments to the gas valve or if the main PCB has been replaced.

ATTENTION Gas type and appliance fan speed (output) must be set according to the specific appliance

specification. Vokera accepts no responsibility if the gas type and/or fan speed is not correctly adjusted according to the respective appliance specification as detailed on the appliance data badge.

7.3.1 CHECKING/ADJUSTING THE APPLIANCE FAN SPEEDS

Move the selector switch to the OFF position and remove the 3-selector knobs.

7.3.2 ABSOLUTE MAX FAN SPEED

Locate the MAX trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table 7.3.6). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

7.3.5 HEATING FAN SPEED

Locate the HTG trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table 7.3.6). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

fig. 36

7.3.6 FAN SPEED TABLE

Use the following table to set the corresponding fan speeds that are relative to the appliance you are working on.

FAN SPEED (rpm) TABLE MODEL MAX MIN HTG IGN

28HE 6100 1700 4400 3700 32HE 5900 1500 4500 3700 36HE 6300 1400 5200 3700

7.4 CHECKING THE CO GAS VALVE

AND ADJUSTING THE

THE GAS VALVE MUST BE SET-UP OR ADJUSTED WITH THE AID OF A PROPERLY CALIBRATED FLUE GAS ANALYSER.

Isolate the appliance from the electrical supply and remove the appliance casing as described in

4.7.1. Set the flue gas analyser to read CO insert the probe into the flue analysis test point (A, B fig. 35). Restore the electrical supply to the boiler and switch the boiler to the OFF mode. To adjust the gas valve you must first ensure that the fan speed potentiometers (trimmers) have been set correctly (see 7.3).

Remove the 3-selector knobs, locate and press the CO button (see fig. 36). The appliance will now operate in CO mode for approximately 15-minutes (see 7.10).

7.4.1 GAS VALVE MAXIMUM SETTING

Locate and gently turn the HTG trimmer till the maximum value fan speed (max) is obtained and check that it corresponds with the appropriate CO value (Maximum) for the respective appliance. If the CO minimum setting (7.4.2).

However, If the CO maximum gas pressure must be adjusted as

reading is correct, proceed to gas valve

reading is incorrect, the

follows:

• Using a 2.5mm Allen key, very slowly turn the maximum adjustment screw (see fig. 37) – clockwise to decrease, counter clockwise to increase – until the correct value is displayed on the CO stabilise).

analyser (allow time for the analyser to

and

Page 27

Maximum

Compensation

pipe connection

fig. 37

screw

Minimum

screw

7.4.2 GAS VALVE MINIMUM SETTING

Locate and gently turn the HTG trimmer till the minimum value fan speed (max) is obtained and check that it corresponds with the appropriate CO value (Minimum) for the respective appliance. If the CO until the correct value is obtained for the respective

reading is correct, rotate the HTG trimmer

appliance (see fan speed table) and proceed to

7.4.3. However, If the CO minimum gas pressure must be adjusted as

reading is incorrect, the

follows:

• Using a suitable screwdriver, very slowly turn the minimum adjustment screw (see fig. 38) – clockwise to increase, counter clockwise to decrease - until the correct value is displayed on the CO stabilise).

analyser (allow time for the analyser to

7.4.3 COMPLETION

On completion of the combustion analysis check and/or any gas valve adjustment, set the HTG trimmer to the corresponding value as detailed in the fan speed table. Refit the 3-selector knobs and move the mode selector to the OFF position. Remove the test probe from the test point and refit the sealing screw/s and/or cap.

IMPORTANT A GAS SOUNDNESS CHECK MUST BE CARRIED OUT IF ANY GAS CARRYING COMPONENTS HAVE BEEN REMOVED, REPLACED, OR DISTURBED .

7.5 COMBUSTION ANALYSIS TEST

A combustion analysis check can easily be carried out on the appliance via the test points located on the top of the appliance (see 7.4).

• Insert the flue gas analyser probe into the flue

gas test point (see fig. 35).

• Operate the boiler in CO mode and compare the

values with those shown in section 2 (Nat. Gas) or section 10 (LPG). If different adjust the gas valve according to 7.4.1, 7.4.2, & 7.4.3.

7.6 CHECKING THE EXPANSION VESSEL

Carry out the component removal procedure as described in 6.4. You must ensure that the boiler is completely drained of water. Using a suitable pressure gauge, remove dust cap on expansion vessel and check the charge pressure. The correct charge pressure should be 1.0 bar ± 0.1 bar. If the charge pressure is less, use a suitable pump to increase the charge.

NOTE

You must ensure the drain valve is in the open position whilst re-charging takes place. Replace the dust cap and carry out the relevant commissioning procedure (section 5).

7.7 EXTERNAL FAULTS

Before carrying out any faultfinding or component replacement, ensure the fault is not attributable to any aspect of the installation.

7.7.1 INSTALLATION FAULTS

Symptom Possible cause

No display/ignition Check wiring/check electrical

supply No hot water Check pipe-work No heating Check external controls

Fault code Possible cause 10 Check gas supply, check flue

system, check polarity

7.8 ELECTRICAL CHECKS

Any electrical checks must be carried out by a suitably qualified person.

7.8.1 EARTH CONTINUITY TEST

Isolate the appliance from the electrical supply, and using a suitable multi-meter carry out a resistance test. Connect test leads between an appliance earth point and the earth wire of the appliance supply cable. The resistance should be less than 1 OHM. If the resistance is greater than 1 OHM check all earth wires and connectors for continuity and integrity.

7.8.2 SHORT CIRCUIT CHECK

Isolate the appliance from the electrical supply, and using a suitable multi-meter, carry out a short circuit test between the Live & Neutral connections at the appliance terminal strip (fig.17). Repeat above test on the Live & Earth connections at the appliance terminal strip (fig.16)

NOTE

Should it be found that the fuse has failed but no fault is indicated, a detailed continuity check will be required to trace the fault. A visual inspection of components may also assist in locating the fault.

7.8.3 POLARITY CHECK

With the appliance connected to the electrical supply and using a suitable multimeter, carry out the following voltage tests:

• Connect test leads between the Live & Neutral connections at the appliance terminal strip (fig.16). The meter should read approximately 230V ac. If so proceed to next stage. If not, see 7.8.4.

• Connect test leads between the Live & Earth connections at the appliance terminal strip (fig.16). The meter should read approximately 230V ac. If so proceed to next stage. If not, see 7.8.4.

• Connect test leads between the Neutral & Earth connections at the appliance terminal strip (fig.16). The meter should read approximately 0 – 15Vac. If so polarity is correct. If not, see 7.8.4.

7.8.4 REVERSED POLARITY OR SUPPLY FAULT

Repeat the above tests at the appliance isolator, if testing reveals correct polarity and/or supply at the isolator, re-check wiring and connections between the isolator and the appliance. If tests on the isolator also reveal reversed polarity or a supply fault, consult the local electricity supplier for advice.

7.8.5 RESISTANCE TO EARTH CHECK

Isolate the appliance from the electrical supply, and using a suitable multi-meter carry out a resistance test. Connect test leads between the Live & Earth connections at the appliance terminal strip (fig. 16). If the meter reads other than infinity there is a fault that must be isolated, carry out a detailed continuity check to identify the location of the fault.

Page 28

These series of checks must be carried out before attempting any faultfinding procedures on the appliance. On completion of any task that required the disconnection and re-connection of any electrical wiring or component, these checks must be repeated.

7.9 FAULT FINDING

Before attempting any faultfinding, the electrical checks as detailed in 7.8 must be carried out. Isolate the appliance from the electrical supply. Disconnect any external controls from terminal plug M6 (Fig. 16), and insert a link-wire between the two wires at the ‘TA’ connections (Fig. 19).

NOTE

Restore the electrical supply to the boiler and turn the selector switch to the on position. The boiler should now function as described in section 7.2. Should the boiler fail to respond, the internal fuses and connectors should be checked to ensure integrity and continuity. If the boiler still fails to respond, refer to the detailed faultfinding flowcharts located at the end of this section.

7.10 BOILER CONFIGURATION

The boiler can be configured by means of the JUMPER Tag which configuration is shown in the below:

JP4 CONFIGURATION

●●

● JUMPER ON POSITION 1: FLOOR

●●

HEATING (IF SET)/STANDARD HEATING (IF NOT USED)

●●

● JUMPER ON POSITION 2: (UNUSED)

●●

● JUMPER ON POSITION 3: (UNUSED)

●●

● JUMPER ON POSITION 4: (UNUSED)

●●

● JUMPER ON POSITION 5: COMBI

●●

● JUMPER ON POSITION 6: (UNUSED)

●●

JP4

7.12 COMPONENT VALUES & CHARACTERISTICS

COMPONENT VALUE

Fan 230Vac Pump 230Vac Valve actuator (Combi only) 230Vac Ignition transformer 230Vac Gas valve 230Vac Room thermostat connection 230Vac NTC thermistor (dry contact) 10Kohm NTC thermistor (wet contact) 10Kohm

FUNCTION VALUE

Standard Heating temperature range (min – max 0C) 40 - 80 Floor Heating temperature range (min – max 0C) 20 - 45 DHW temperature range (min – max 0C) 35 - 60 75% maximum CH time 15 min Heating OFF hysterisis (0C) SP + 5 Heating ON hysterisis (0C) SP – 5 DHW OFF hysterisis (0C) SP + 5 DHW ON hysterisis (0C) SP + 3 Anti-cycle delay 3-min Pump over-run 30-sec Low output (min. output + %) Min+25 CO function max temp. (0C) 95 CO re-light temp. (0C) 75 CO function time 15-min Flow NTC max temp. (0C) 95 High limit thermostat (0C) 105 Burner thermostat (0C) 170 Maximum differential (0C) 35

IGNITION CONTROL VALUE

Ignition attempts before L/O (lockout) 5 Re-ignition attempts after loss of flame signal 5

FOR CONFIGURATION SEE REFERENCE NUMBER (PIN1 ON PCB) AS SHOWN IN BELOW.

7.11 FAULT CODES

When the boiler detects a temporary fault condition, the appropriate code is shown flashing on the display. If/when the fault code is final, the pump will perform a 60-second post circulation and the red LED will be illuminated.

CODE CAUSE ALARM TYPE ACTION

AL10 Ignition failure/not flame sensed, Final Reset, check appliance operation

condense sensor activated

AL20 Limit thermostat fault Final Reset, check appliance operation

AL21 External device fault (UHT/CPA) Final Reset, check appliance

AL26 Return temperature too high Final Reset, check pump, ensure there is circulation

around heating circuit/s thenmistor

AL28 Temperature differential inverted Final Reset, check pump, ensure there is sufficient

(return sensor temperature higher than circulation around heating circuit/s thermistors flowsensor temperature)

AL34 Fan tacho signal fault Final Reset check appliance operation, check fan

AL40 Insufficient system water pressure Final Check/refill system pressure, reset, check

appliance operation

AL41 Insufficient system water pressure Temporary Check/refill system pressure, check

appliance operation

AL52 Internal fault Final Reset, check appliance operation

AL55 Jumper tag fault Final Check jumper tag configuration

AL60 DHW thermistor fault Temporary Check DHW thermistor

AL71 Primary (flow) thermistor fault Temporary Check primary thermistor, check wiring

AL73 Return thermistor fault Temporary Check return thermistor, check /wiring

AL74 Variation on temperature of primary Final Reset, check appliance operation, check

and/or return too high pump, ensure there is sufficient circulation

around heating circuit/s

AL79 Flow temperature too high, or Final Reset, check appliance operation, check

Page 29

SECTION 8 WIRING DIAGRAMS

8.1 EXTERNAL WIRING

The appliance comes with a factory fitted (TA) link to allow basic operation of the boiler via the mode selector switch. If external controls are to be added to the system, they must be connected to the appliance as shown in the following diagrams. For advice on controls that are not featured in this book, please contact Vokera technical on 0870 333 0520.

8.1.1 EXTERNAL WIRING LIMITATIONS

Any external wiring must remain within the limits as detailed in the table below

CONNECTION MAX. LENGTH

External sensor 30-metres Room thermostat 30-metres OT+ connection 30-metres

8.2 TYPICAL CONTROL APPLICATIONS

The appliance can be used with the following controls:

• Single-channel, voltage-free time clocks (fig.

39).

• Programmable room thermostats (fig. 40).

• OT+ control, please contact Vokera technical

for detailed instruction on specific OT+ controls.

• Vokera external sensor.

Isolate the appliance from the electrical supply and remove the clock blanking disc from the clock aperture on the boiler. Keep the screws safe, as they will be required to secure the programmer to the aperture.

Connect the spade connections of the wiring harness to the clock as shown in figure 39. Connect the other end of the wiring harness as detailed in figure 41. Secure the clock to the clock aperture using the screws previously removed from the blanking disc.

IMPORTANT

• The boiler must always be supplied with a permanent 230V electrical supply.

• Always remove the link between TA & TA on the appliance high-voltage terminal strip whenever additional controls are connected to the appliance.

• Do not connect any controls or auxiliary equipment to the low-voltage terminal strip, other than that approved/supplied by Vokera Ltd.

8.3 OTHER DEVICES

Contact the controls manufacturer and/or Vokera technical department should you require more specific information on the suitability of a particular control. Further guidance on the recommended practice for the installation of external controls, can be found in CHeSS – HC5/HC6 (www.energyefficiency.gov.uk).

8.4 VOKERA MECHANICAL CLOCK (code )

The Vokera mechanical clock (product code) is entirely suitable for the Unica HE range and eliminates the need for an external time control. The kit is comprised of the following:

• Mechanical clock

• Wiring harness

• instructions

Fig. 40

OPTIONAL DEVICE (24V) TERMINAL BLOCK

Fig. 39

Fig. 41

U.H.T. = underfloor heating thermostat C.P.A.= condensate pump alarm E.S.= external sensor OT+= opentherm + connection

Page 30

FUNCTIONAL DIAGRAM

Fig. 38

NOTE: L-N-E connection is advisable

F Hv Fan power supply 230 V F Lv Fan signal control P Pump F Fuse 3.15A F (fast) F1-F2 Fuse 3.15A T (delay) OPE Gas valve solenoids S.E. (1) Spark electrode S.E. (2) Sense electrode C.S. Condensate sensor G.V. Gas valve TSC1 Ignition transformer TR2 PCB transformer E.S External sensor WPS Water pressure switch FS Flow thermistor (NTC) RS Return thermistor (NTC) AD01A Main PCB CN1÷CN5 Connection to PCB high voltage X2÷X16 Connection to PCB low voltage F.O.H.T Flow over heat thermostat H.E.T Heat exchanger thermostat

M3-M5 Terminal strip for supply in / clock / room thermostat M3a-M4 Terminal strip for esternal sensor / condense pump / low

temperature thermostat OT+ Open therm + connection D.H.W.F.S Domestic hot water flow switch D.H.W.T Domestic hot water temperature 3W 3 way motor JP5 For combi boiler X1 Connector minitank (unused) CN12 Service connector SW1 Co button A1 24V output to 2CH - programmer P1 DHW potentiometer P2 Heating potentiometer P3 Selector switch R9 Trimmer for maximum output R10 Trimmer for minimum output R14 Trimmer for ignition fan speed R19 Trimmer for heating fan speed R35 Trimmer thermoregulation UHT Underfloor heating thermostat CPA Condensate pump alarm

Page 31

SECTION 9 EXPLODED DIAGRAMS

28 HE

Table 1

226

300

301

226

30 HE/35 HE

300

POS. DESCRIPTION 28 HE 32 HE 36 HE

1 Frame assembly 01005403 01005446 01005406 12 Pressure gauge 2564 2564 2564 18 Cover assembly 10028554 10028554 10028554 20 Printed Circuit Board 10028558 10028558 10028558 21 Led light guide 10028557 10028557 10028557 26 Front panel 10028632 10028632 10028632 27 Knob assembly 10028559 10028559 10028559 31 Case assembly 10028448 10028451 10028451 40 Door panel 10028553 10028553 10028553 78 Cover assembly 01005442 01005442 01005442 90 Fuse 3478 3478 3478 226 Edge clip 5128 5128 5128 300 Wiring harness 10028593 10028593 10028593 301 Wiring harness 10028596 10028596 10028596 302 Wiring harness 10028634 10028634 10028634

226

301

226

Page 32

Table 2

439

353

366

28 HE 32 HE/36 HE

201

288

521

439

438

433

201

436

441

438

433

432

435

288

435

432

351

353

266

366

442

288

432

266

265

328

433

288

432

290

351

328

444

443

432

201

434

265

328

351

439

353

366

438

433

432

288

435

432

353

266

201

436

441

288

435

266

351

328

366

521

439

438

433

288

432

442

290

351

432

265

444

443

201

288

432

201

434

265

328

351

POS. DESCRIPTION 28 HE 32 HE 36 HE

1 Condensing exchanger assembly 8037 1957 10024627 2 Fitting/union 10024640 10024640 10024640 3 Pressure switch 10028141 10028141 10028141 4 Non return valve 10025056 10025056 10025056 6 By-pass casing 10024641 10024641 10024641 7 Heating by-pass valve 2047 2047 2047 9 3-way heating manifold and cartridge 10026508 10026508 10026508 10 3 way valve cartridge 10025305 10025305 10025305 11 Motorised valve 10025304 10025304 10025304 12 Clip 10025450 10025450 10025450 13 Clip 10025449 10025449 10025449 22 Safety valve 10025055 10025055 10025055 24 10 lt. flow governor 10024987 10025080 10026046 24 10 lt. flow governor 10026044 10026041 10026041 24 10 lt. flow governor 10026045 10026045 10026042 25 Pipe 10025839 10025839 10025839 26 Dhw actuator 10022349 10022349 10022349 27 Heating cock 1789 1789 1789 28 Connection 1790 1790 1790 30 1/8 heating deviation cock 10023567 10023567 10023567 34 1/8 heating deviation cock 10023566 10023566 10023566 35 Flexible oil line 10023570 10023570 10023570 37 Pipe 10025840 10025840 10025840 47 Cover for by-pass assembly 10024643 10024643 10024643 48 Cock 10024646 10024646 10024646 61 Non return valve 10023569 10023569 10023569 62 1/8 heating deviation cock 10023568 10023568 10023568 63 Pipe 10026228 10026228 10026228 201 Washer 5026 5026 5026 265 Washer 5236 5236 5236 266 Washer 5237 5237 5237 288 Ring 6898 6898 6898 290 Clip 2165 2165 2165 328 Clip 1890 1890 1890 351 Nut 1823 1823 1823 353 Nut 1824 1824 1824 366 Clip 1820 1820 1820 432 Clip 10024958 10024958 10024958 433 Clip 10024986 10024986 10024986 434 1/2" nipple 10024985 10024985 10024985 435 Fitting/union 10025059 10025059 10025059 436 Clip 10025062 10025062 10025062 438 O ring 10024988 10024988 10024988 439 Washer 10025067 10025067 10025067 441 Clip 10025063 10025063 10025063 442 O ring 10025065 10025065 10025065 443 O ring 10025064 10025064 10025064 444 Washer 10025066 10025066 10025066 521 Ntc sensor 10027351 10027351 10027361

Page 33

Table 3

28 HE 32 HE/36 HE

478

476

287

477

476

477

478

287

476

477

201

290

478

247

200

290

476

200

201

372

512

290

477

478

247

200

290

200

512

372

POS. DESCRIPTION 28 HE 32 HE 36 HE

1 Expansion vessel 2204 2573 2573 2 Pipe 10025188 10025188 10025188 3 Pump 10027571 10027571 10027571 4 Wiring harness (pump) 10028633 10028633 10028633 6 Pipe 10028428 10026264 10026264 7 Pipe 10027317 10027317 10027317 9 Pipe 10028429 10028263 10028264 10 Pipe 10028631 10028643 10028643 17 Air venting plug 10026275 10026275 10026275 25 Siphon 10028405 10028405 10028405 26 Condensing pipe 10028540 10027191 10027191 27 Condensing pipe 10027192 10027192 10027192 66 Condensing pipe 10028539 10026272 10026272 71 Pipe 10028430 10028516 10028515 72 Venting-plug 01005137 01005137 01005137 73 Cock 10028431 10028431 10028431 200 Washer 5023 5023 5023 201 Washer 5026 5026 5026 247 Washer 5203 5203 5203 287 High limit thermostat 2258 2258 2258 290 Clip 2165 2165 2165 302 Washer 2588 2182 2182 372 Clip 2588 2588 2588 476 O ring 10026324 10026324 10026324 477 Split pin 10026269 10026269 10026269 478 Ntc sensor 10026273 10026273 10026273

512 Washer 10027193 10027193 10027193

Page 34

Table 4

28 HE 30 HE/35 HE

600

200

500

479

501

486

502

497

600

200

500

479

501

486

502

497

POS. DESCRIPTION 28 HE 32 HE 36HE

1 Roomsealed chamber 10028341 10028447 10028447 2 Side 10026231 10026231 10026231 3 Fan 10028456 10028456 10028456 4 Burner 10028537 10028642 10028537 5 Spark/ignition electrode 10027864 10027864 10027864 6 Condense electrode 10026316 10026316 10026316 12 Gas pipe 10028620 10026318 10026318 13 Gas valve 10028538 10028538 10028538 15 3/4" gas cock 10020897 10020897 10020897 16 Air box cover 10028345 10026230 10026230 19 Glass stopper assembly 10026328 10026328 10026328 27 Plug 10023805 10023805 10023805 35 Air gas conveyor 10028420 10028420 10028420 39 Gas pipe 10028424 10028204 10028206 46 Gas diaphragm 10027161 10027161 10027162 67 Washer 10026322 10026322 10026322 69 Tryton 10028425 10028425 10028425 72 Mixer 10024295 10024295 10024295 79 Flame detection electrode 10028422 10028422 10028422 200 Washer 5023 5023 5023 479 Transformer 10026237 10026237 10026237 486 O ring 10026325 10026325 10026325 497 Washer 10026796 10026796 10026796 500 Wiring harness 10028599 10028599 10028599 501 Wiring harness (gas valve) 10028600 10028626 10028626 502 Spark electrode cable 10026558 10026558 10026558 600 Lpg conversion kit 01005447 01005447 01005448

Page 35

Table 5

28 HE

487

552

600

601

509

482

30 HE/35 HE

475

487

600

601

552

475

POS. DESCRIPTION 28 HE 32 HE 36 HE

1 Condensing exchanger assembly 01005443 01005366 01005369 7 Conveyor 10028536 10028623 10028623 12 Flue drain connection 10028421 10028421 10028421 475 Washer 10026323 10026323 10026323 482 Washer 10026366 10026366 10026366 487 Washer 10026345 10026345 10026345 509 High limit thermostat 10026982 10026982 10026982 552 Washer 10028426 10028426 10028426 600 Wiring harness (gas valve) 10028595 10028601 10028601 601 Wiring harness 10027360 10027360 10027360

509

482

Page 36

SECTION 10 LPG INSTRUCTIONS

10.1 RELATED DOCUMENTS

BS 5440 PARTS 1 & 2 FLUES & VENTILATION REQUIREMENTS

BS 5449 PART 1 FORCED CIRCULATION OF HOT WATER SYSTEMS

BS 5482 PART 1 DOMESTIC BUTANE & PROPANE GAS BURNERS IN PERMAMENT

BS 5546 INSTALLATION OF GAS HOT WATER SUPPLIES FOR DOMESTIC

BS 6798 INSTALLATION OF BOILERS OF RATED NOT EXCEEDING 60kW

10.2 Gas Pressures Unica 28HE Unica 32HE Unica 36HE

Inlet pressure 37.0mbar

Maximum gas rate (kg/hr) 2.17 2.48 2.80 Minimum gas rate (kg/hr) 0.47 0.54 0.54 Injector size 4.7mm 4.7mm 5.0mm CO2 max (%) 10.0 10.0 10.0 CO2 min (%) 10.0 10.0 10.0 CO max (mg/kWh) 182.8 215.0 236.5 CO max (mg/kWh) 32.3 21.5 21,5 NOx max (PPM) mg/kWh 70.6 88.3 88.3

NOx min (PPM) mg/kWh 53.0 53.0 70.6 CO/CO2 ratio @ max 0.002 to 1 0.002 to 1 0.002 to 1

CO/CO2 ratio @ min 0.002 to 1 0.002 to 1 0.002 to 1

SEDBUK ‘A’ (%) 92.4 92.7 92.7

DWELLINGS

PURPOSES

10.3 CONVERTING THE APPLIANCE GAS TYPE

To convert the appliance to another gas type it is necessary to change the burner injector, adjust the appliance fan speeds, and adjust the gas valve (CO

• To change the injector see 6.12.1

• To adjust the fan speeds see 10.7

• To adjust CO2 values see 10.6

10.4 GAS SUPPLY

The gas supply must be connected to the appliance by a competent LPG installer and must be of sufficient size to supply the appliance at its maximum output. An existing supply must be checked to ensure that it is of adequate size to deal with the maximum rated input of this and any other appliances that it serves.

10.5 GAS SUPPLY INSTALLATION

The entire installation including the meter must be purged and checked for gas soundness.

10.6 ADJUSTING THE GAS VALVE THE GAS VALVE MUST BE SET-UP OR ADJUSTED WITH THE AID OF A PROPERLY CALIBRATED FLUE GAS ANALYSER.

10.6 CHECKING THE CO2 AND ADJUSTING THE GAS VALVE

THE GAS VALVE MUST BE SET-UP OR ADJUSTED WITH THE AID OF A PROPERLY CALIBRATED FLUE GAS ANALYSER. Isolate the appliance from the electrical supply and remove the appliance casing as described in

4.7.1. Set the flue gas analyser to read CO2 and insert the probe into the flue analysis test point (A, B fig. 35). Restore the electrical supply to the boiler and switch the boiler to the OFF mode. To adjust the gas valve you must first ensure that the fan speed potentiometers (trimmers) have been set correctly (see 10.7). Remove the 3-selector knobs, locate and press the CO button (see fig. 36). The appliance will now operate in CO mode for approximately 15-minutes (see 7.10).

10.6.1 GAS VALVE MAXIMUM SETTING

Locate and gently turn the HTG trimmer till the maximum value (fan speed) is obtained and check that it corresponds with the appropriate CO2 value (Maximum) for the respective appliance. If the CO2 reading is correct, proceed to gas valve minimum setting (10.6.2). However, If the CO2 reading is incorrect, the maximum gas pressure must be adjusted as follows:

• Using a 2.5mm Allen key, very slowly turn the maximum adjustment screw (see fig. 38) – clockwise to decrease, counter clockwise to increase – until the correct value is displayed on the CO2 analyser (allow time for the analyser to stabilise).

10.6.2 GAS VALVE MINIMUM SETTING

Locate and gently turn the HTG trimmer till the minimum value (fan speed) is obtained and check that it corresponds with the appropriate CO2 value (Minimum) for the respective appliance. If the CO2 reading is correct, rotate the HTG trimmer until the correct value is obtained for the respective appliance (see fan speed table) and proceed to

10.6.3.

However, If the CO2 reading is incorrect, the minimum gas pressure must be adjusted as follows:

10.6.3 COMPLETION

Page 37

IMPORTANT A GAS SOUNDNESS CHECK MUST BE CARRIED OUT IF ANY GAS CARRYING COMPONENTS HAVE BEEN REMOVED, REPLACED, OR DISTURBED .

FAN SPEED (rpm) TABLE - LPG

MODEL MAX MIN HTG IGN

28HE 6100 1700 4300 3700

32HE 5900 1500 4500 3700

36HE 6300 1400 5200 3700

10.7 APPLIANCE FAN SPEEDS

The appliance fan speeds require to be checked and/or adjusted prior to making any adjustments to the gas valve or if the main PCB has been replaced.

ATTENTION Gas type and appliance fan speed (output) must be set according to the specific appliance

specification. Vokera accepts no responsibility if the gas type and/or fan speed is not correctly adjusted according to the respective appliance specification as detailed on the appliance data badge.

10.7.1 CHECKING/ADJUSTING THE APPLIANCE FAN SPEEDS

Move the selector switch to the OFF position and remove the 3-selector knobs.

10.7.2 ABSOLUTE MAX FAN SPEED

Locate the MAX trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table above). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

10.7.3 ABSOLUTE MIN FAN SPEED

Locate the MIN trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table above). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

10.7.4 IGNITION FAN SPEED

Locate the IGN trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table above). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

10.7.5 HEATING FAN SPEED

Locate the HTG trimmer (fig. 36) and gently adjust clockwise or counter clockwise to achieve the correct fan speed (see table above). NOTE, the display shows the fan RPM in multiples of 1000, i.e. 2.5 = 2500RPM.

Page 38

BENCHMARK No.

COLLECTIVE MARK

GAS BOILER COMMISSIONING CHECKLIST

BOILER SERIAL No. NOTIFICATION No.

CONTROLS

TIME & TEMPERATURE CONTROL TO HEATING ROOM T/STAT & PROGRAMMER/TIMER PROGRAMMABLE ROOMSTAT

TIME & TEMPERATURE CONTROL TO HOT WATER CYLINDER T/STAT & PROGRAMMER/TIMER

HEATING ZONE VALVES FITTED NOT REQUIRED

HOT WATER ZONE VALVES FITTED NOT REQUIRED

THERMOSTATIC RADIATOR VALVES FITTED

AUTOMATIC BYPASS TO SYSTEM FITTED NOT REQUIRED

To comply with the Building Regulations, each section must have a tick in one or other of the boxes

COMBI BOILER

FOR ALL BOILERS CONFIRM THE FOLLOWING

THE SYSTEM HAS BEEN FLUSHED IN ACCORDANCE WITH THE BOILER MANUFACTURERS INSTRUCTIONS?

THE SYSTEM CLEANER USED

THE INHIBITOR USED

FOR THE CENTRAL HEATING MODE, MEASURE & RECORD

N/A

/hr

GAS RATE

BURNER OPERATING PRESSURE (IF APPLICABLE)

CENTRAL HEATING FLOW TEMPERATURE °C

CENTRAL HEATING RETURN TEMPERATURE °C

/hr

FOR COMBINATION BOILERS ONLY

HAS A WATER SCALE REDUCER BEEN FITTED? YES NO

WHAT TYPE OF SCALE REDUCER HAS BEEN FITTED?

FOR THE DOMESTIC HOT WATER MODE, MEASURE & RECORD

N/A

/hr

GAS RATE

MAXIMUM BURNER OPERATING PRESSURE (IF APPLICABLE) mbar

COLD WATER INLET TEMPERATURE °C

HOT WATER OUTLET TEMPERATURE °C

WATER FLOW RATE

FOR CONDENSING BOILERS ONLY CONFIRM THE FOLLOWING

THE CONDENSATE DRAIN HAS BEEN INSTALLED IN ACCORDANCE WITH THE MANUFACTURERS INSTRUCTIONS? YES

FOR ALL INSTALLATIONS CONFIRM THE FOLLOWING

THE HEATING AND HOT WATER SYSTEM COMPLIES WITH CURRENT BUILDING REGULATIONS

THE APPLIANCE AND ASSOCIATED EQUIPMENT HAS BEEN INSTALLED AND COMMISSIONED IN ACCORDANCE WITH THE MANUFACTURERS INSTRUCTIONS

IF REQUIRED BY THE MANUFACTURER, HAVE YOU RECORDED A CO/CO2RATIO READING? N/A YES CO/CO2RATIO

THE OPERATION OF THE APPLIANCE AND SYSTEM CONTROLS HAVE BEEN DEMONSTRATED TO THE CUSTOMER

THE MANUFACTURERS LITERATURE HAS BEEN LEFT WITH THE CUSTOMER

/hr

lts/min

COMMISSIONING ENGS NAME

PRINT CORGI ID No.

SIGN DATE

Page 39

SERVICE INTERVAL RECORD

It is recommended that your heating system is serviced regularly

and that you complete the appropriate Service Interval Record Below.

Service Provider. Before completing the appropriate Service Interval Record below, please ensure you have carried out the service

as described in the boiler manufacturers instructions. Always use the manufacturers specified spare part when replacing all controls

SERVICE 1

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 3

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 5

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

DATE

SERVICE 2

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 4

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 6

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

DATE

SIGNATURE

SERVICE 7

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 9

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

DATE

SIGNATURE

SERVICE 8

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

SERVICE 10

ENGINEER NAME

COMPANY NAME

TEL No.

CORGI ID CARD SERIAL No.

COMMENTS

SIGNATURE

DATE

Page 40

Cod. 10028635 - 06/06 - Ed. 1

Registered address:

Vokèra Ltd

Borderlake House

Unit 7 Riverside Industrial Estate

London Colney Herts AL2 1HG

enquiries@vokera.co.uk

www.vokera.co.uk

www.vokera.ie

Sales, General Enquires

T 0844 391 099

F 0844 391 0998

Vokèra Ireland

West Court, Callan

Co Kilkenny

T 056 7755057 F 056 7755060

Vokèra Limited reserve the right to change

specification without prior notice

Consumers statutory rights are not affected.

A Riello Group Company.

Company Reg No: 1047779

vokera Unica 28 HE User guide

Specifications and Main Features

Frequently Asked Questions

User Manual