Vokera 12-48 RSE Mynute INSTALLATION AND SERVICING INSTRUCTIONS

Page 1

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CONTEN	TS
Section	Subject	Page No.	Section	Subject	Page
Section 1	Introduction	-	6.11	Final check of operations	14
	General Layout Schematic Diagram	2 1	6.12 6.13	Concluding Operations Refixing the front cover	14 14
Section 2	Design Principles and		Section 7	Instructing the User	14
	Operating Sequence		000000000000000000000000000000000000000		3
2.2	Central Heating 2.2.1-2.2.2	2	Section 8	Servicing Instructions
2.3	Safety Devices	2	8.1	General	ರ
			8.2	Important Notes	5
Section 3	lechnical Data		8.3	Recommended Houtine	ħ
3.1	Units	မ	84	Servicing	ನೆ ರ
а (З 2 С	Dimensions and Contents	ິ	8.5	To remove/replace room sealed	ē
5 C	Connection sizes	ະບ	0.0	chamber front cover	ธ
ა.4 ი 4	Installation requirements	ى د	8.6	To remove/replace Electrode	ā
ີ່	Liectifical Details	ω c		& Main Burner	17
3.7	Burner Details	ω	8.7	To remove Main Burner Injectors	17
			8.8 0	To Remove Main Heat Exchanger	₫
Section 4	General Requirements		01.8 9.9	To Bemove Flue Fan	α
4.1	Related Documents	4		Switch	8
4.2	Coo Supply	- 1	8,11	To Remove Combustion
4.4	Flue System	4		Chamber and Insulation Panels	19
4.5	Air Supply	თ	8.12	Control Valve Operator and
4.6	Water Circulation	n U		Solenoid	19
4.7	Electrical Supply	7 0	8.13	To Remove Gas Control Valve	5
			814	Complete To Remove Pump	25
o uonoec	Installation		8.15	To Remove Heating Manifold	20
5.1	Delivery	000	8.16	Removal of Main Expansion
лU	Unpacking Branaring for Mounting	α	•	Vessel	20
л 0.0	Fieparitig for Mounting	οα	8.17	Removal of Safety Valve	21
5.5 5.4	Fitting the Flue	မပ	8.18	Components	2
5.6	Connecting the gas and water		8.19	Removal of Mechanical	ŗ
57	supplies Electrical Connections	= =		Instruments and Components	22
Section 6	Commissioning and Testing		Section 9	Operation Checks, Wiring	3
2		3
6.2	Gas Supply Installation	75 75		Fault finding Charts	24 - 27
6.3	Central Heating System	12	Section 10	Appendix
6.4	Electrical Supply	12		Instructions for fitting Optional
ດ.ບ		5 7		Time Clocks	28 - 31
6.7 6.7	Checking the flue system	5 5		Exploded Diagrams	32 - 36
6.8	Checking the Heating	2		Short Spare Parts List	36
	Thermostat	13		Functional Flow Diagram	37
6.9	Regulating the Heating system	13		General layout of winnig Illustrated Wiring Diagram	а С
6.10	Final flushing of the heating			Q	1
	ayatelli	Ŧ

SECTION 1 INTRODUCTION

The Vokera 12-48 RSE Mynute is a central heating boiler which by design incorporates a circulating pump, expansion vessel, safety valve, temperature gauge, pressure gauge, automatic by-pass and electronic ignition.

applications only. It is provided with a fan powered flue outlet with an annular co-axial combustion air intake which can be rotated through 360 degrees. appliance suitable for wall mounting

12-48 Mynute

is possible by the addition of an indirect cylinder with 'Y' or 'S' plan controls.

Fig.1

Pressure Differential Switch

Spark Electrode
Automatic Air Release Valve
High Limit Stat
Pressure Gauge Safety Thermostat
Electronic Ignition Control Box Fan Overrun Thermostat
Gas Cock
Boiler Flow Switch

Safety Valve Return Valve Flow Valve

20 Central Heating Manifold 21 Boiler Thermostat

26 Sens 27 Fan

Sensing Electrode

25 Gas Valve 24 Pump

23 Mode Selector Switch 22 ON/OFF Switch

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SECTION 2 DESIGN PRINCIPLES AND OPERATING SEQUENCE

principles described below. Fig 1 illustrates the general layout of components. Fig 2 illustrates the operating

CENTRAL HEATING

burner ignition is checked by the electronic both the gas valve and the electronic ignition circuitry allowing an ignition attempt. The are started. The flow of water from the pump operates a flow switch. This in turn energises when the various switches and controls impose a demand for heat, the fan and pump
As water temperature increases this is sensed by the thermostat (21) which eventually

2.3

which prevents burner operation if the water (A) Differential pressure unit in the circuit
(B) A high limit thermostat, which interrupts
A safety valve is provided to relieve excess

2.3.1

з.1 UNITS

SECTION 3

TECHNICAL DATA

Height: 880mm (34.5in) overall DIMENSIONS AND CONTENTS

: 360mm (14.2in) 345mm (13.6in

ა ა CONNECTION SIZES

supplied with boiler Flue outlet: nom. dia. 100mm specially Gas Service Rc 1/2 (1/2in BSP int) Safety valve outlet: Rc 1/2 (1/2 BSP int)

3.4

3.4.1

NOTE: Vertical flue Minimum-at sides 25mm (11n) (from casing) Minimum-in front 600mm (24in) (from casing
3.4.2 maximum nearing system contents approx
63 litres (14 gals) litres (1.3 gals). Acceptance capacity of expansion vessel 6
3.4.3 Air supply/ventilation: To requirements of BS 5440 Part 2 1989.
3.4.4 Means of filling sealed system: To accord with BS and/or local Water Authority
3.4.5 Side flue: 890mm (to centre line of boiler Rear flue: 700mm (wall thickness) maximum length of duct as follows The standard flue duct assembly allows a

Fig. 3

but for each bend used the maximum length of straight flue is reduced by .75 metres. e.g. 1 extra bend plus 3.75 metres of straight extended to a maximum of 4.5 metres in a straight line. A maximum of two extra 90 degree bends may be used (Section 5.5.20

ω 5 ELECTRICAL DETAILS

mains supply 240/250v ~ 50Hz Fused 3/ ower consumption: 190w

3.6 PERFORMANCE

Min 9.2kW (31,400Btu/h) Nominal Heat Input Max. 17.6kW (60,000Btu/h)

Max. 14kW (48,000 Btu/h) Min. 6.7kW (22,860 Btu/h)

Max Pressure 10.6 mbar (4.3in wg

Maximum 1.5 bar/15m.wg/50ft w.g. Minimum 0.5 bar/5m.wg/16ft w.g Safety valve setting 3 bar/30m/102ft

appliance 350 litres/hour (1.28 gals/min) Minimum central heating flow rate through

Max. Gas Rate 1.68m³/h 59.4tt³/h Min. Gas Rate 0.92m³/h 32.5tt³/h

Main Burner Injectors 7 x 1.35 Main Burner: Polidoro BURNER DETAILS type NP7

3.7

the appliance heating system after allowing

÷ 130

1 20

4.00 3.7 ្ពុខ្ល 2.9 2.6 2 8 : 8 5 ĝ

± 8 °, 28

2 0

gpm

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SECTION 4 GENERAL REQUIREMENTS

GENERAL REQUIREMENTS

gas safety (installation & use) Regulations This appliance must be installed by a


BS 6891		1988	Low pressure installation pipes
BS 6798		1987	Boilers of rated input not exceeding 60kW
BS 5449	Part 1	1990	Forced circulation hot water system
BS 5440	Part 1	1990	Flues

LOCATION OF APPLIANCE

Part 2

1989

4.2

Regulations applicable in Scotland, with respect to the installation of the boiler in a 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 The boiler may be installed in any room or om or internal space containing a bath c

electrical switch or appliance control a room containing a bath or shower, any where a room-sealed appliance is installed in

permit the provision of a satisfactory flue and termination. The location must also permit an necessary and BS 6798:1987 gives detailed nstallation of the boiler will be in an unusual

provided that it is modified for this purpose

soundness as described in the above code

other appliances ensure that an adequate supply is available both to the boiler and the N.B. If the gas supply for the boiler serves

FLUE SYSTEM

or discoloration that might occur to building

he effect of such steaming must be

a guard of durable material. (6.6tt) above a pavement or plattorm to which (2in) to any combustible material. For protection of combustibles, refer to BS

A suitable guard is manufactured by G.R. Claudio (Vokera) Ltd. Part No 018, (GC No 301 106). This guard must be fitted centrally

TERMINAL POSITION FOR FAN ASSISTED BOILER

opening (e.g. air brick)
From vertical drain pipes and soil pipe

600 300

From a terminal tacing a terminal
From an opening in the car port (e.g. doo window) into dwelling
vertically from a terminal on the same wa

1500 1200

300

wali

4.5

The roomsealed fan flued boiler does not Intended for general guidance in BS5440;2;1989. The following notes are commendations for air supply are detailed

Where installed in a cuppoard of

minimum effective areas of such air vents

high level	OF OF IR VENTS
159cm ² (24.5in ² )	AIR FROM ROOM OR INTERNAL OUTSIDE	AIR VENT
80cm ² (12.3in ² )	AIR DIRECT FROM OUTSIDE	AREAS

outside wall. the same room or space or be on the same i. Both vents must either communicate with

adjacent internal space, it is suggested that the space is adequately ventilated. . Where vents communicate with an

WATER CIRCULATION

4.6 Detailed recommendations are given in BS 6798:1987 and BS 5449:1:1990 (for systems). The following notes are given for

4.6.2 FIFEWORK

compression fittings Copper tubing to BS 2871:1:1971 is recommended for water pipe. Jointing should

points and water flows naturally to drain taps Where possible, pipes should have a gradier

the appliance heat exchanger is not a natura

be paid to pipes passing through ventilated spaces in roofs and under floors. Except where providing useful heat,

4.6.3

boiler and systems should be designed to ensure that with only one radiator turned on a flow rate of at least 350 litres/hour (1.28 gals/ inv) in other of the boilty in the board the boilty of the b An automatic by-pass is incorporated in the

4.6.4 Figs 5&6 illustrate typical heating only layouts, but the boiler is also suitable for installation with a 'Yor'S' plan system. SYSTEM DESIGN

Section 10 appendix D gives wiring details

4.6.5 DRAINING TAPS

accordance with BS 2879:1980 positions to permit the draining of the whole systems. The taps must be least 15mm Inese must be located in accessible

80cm^∠ (12.3in²)

Page 5

AIR RELEASE POINTS

i nese must be fitted at all high points where air will naturally collect, and must be sited to

4.6.7 heated, it can accept up to 6 litres increase of water volume when the system is connected to a system with an unusually

problem

4.6.8 FILLING POINT

area, contact the local authority for preferred this method is not suitable in a particular authority regulations. A method is shown in fig 7 using the Vokera filling loop which is acceptable in most areas. In the event that replacing water lost during servicing must be provided, and it must comply with local water A method for initially filling the system and

cause premature scaling of the main heat N.B. The installer should ensure that no leaks exist as frequent filling of the system could

4.7 ELECTRICAL SUPPLY

The appliance is supplied for operation on 240/250V ~ 50Hz electricity supply. It should e protected with a 3-amp fuse. HIS APPLIANCE MUST BE EARTHED.

or at least 3mm I he preterred method is by using a tused double pole switch with a contact separation

ne switch must supply ONLY the appliance ogrammer/room thermostat)

complying with BS 1363 socket outlet with a fused 3- pin plug both

water supply

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arefully cut out and used prior to installation mark the locations for fixing holes for the

Fittings pack containing central heating alves (2) Installation Manual - Wall Bracket

UNPACKING

Users Instructions

5.2.1 accessories and top packing. Upen the top of the carton and remove
5.2.2 ne noor, restrain the carton, grip the black

0.3 PREPARING FOR MOUNTING

5.3.2 Slightly lift the casing, flex outwards at base and slide it gently towards the top of the
5.3.3
5.3.4
5.4 Refer to fig 9 MOUNTING THE APPLIANCE
5.4.1 Place the template on a smooth, vertical,

dimensions in tig 9.

5.4.2
Drill a 105mm hole through the wall to allow

dimensions for locating the hole. Where it is Herer to rig. 9 and rigs. 10-13 for relevant

5.5 5.5.1 FITTING THE FLUE

Refer to figures 10 13
available to order for flue extensions of up to kits (Part No. 026 G.C. No. 370 346) are for lengths up to 890mm - from the outside of wall to centre of the flue elbow. Extension The flue outlet elbow may be rotated 360
5.5.3 elbow (fig 10) and assemble onto the flue outlet on the top of the boiler. Twist the flue boiler sideways to its correct position. Locate the small maintenance clip on to the flue check that the hole through the wall is at the bend to the outlet direction required, and 4.5 metres total length of straight flue. ue bend in place. Carefully level across to
(Dimension X on Figs 10 & 11). Measure carefully from the actual face of the
dimension of 890mm.
5.5.6 NOTE: The two tubes must be separated by The difference is the precise length to be removed from the inner flue tube (890 - X = Where X is less than 890mm, the supplied emoving screw G (fig 12) before cutting ubtract the measured length from 890mm
EXAMPLE the same amount to allow a gap for easy

off inner tube is 890 - 630 = 260.

5.5.7 ĸ EXAMPLES shorten the tubes accordingly 4 extensions = 4290mn lengths with extension(s) is as follows:-1 extension = 1740mm where X is more than 890mm an extension Subtract X from appropriate figure and measure x ut 5th extension for a Maximum length of extensions = 2590mm (or kits) is needed. The standard uncut
X = 1920 so 2590 1920 = 670 extension by 445mm 1740 - 1295 = 445
TOOTH SAW AND REMOVE BURRS

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5.5.8	Loosen the small maintenance clip and lift off the flue bend
5.5.9	Ensure inner and outer terminal tubes are firmly fitted together with screw G (fig 12) Push the terminal tubes through the wall until the face of the outer tube protrudes 18mm from the face of the wall (fig 12) The terminal
	wall face.
5.5.10	If extension pieces are used assemble these using the maintenance clips provided.
5.5.11	Make sure the entire length of the flue is truly horizontal and adequately supported. Use at
	least one bracket for each extension. (Conventional adjustable strap supports suffice, Vokera stockist can supply if necessary. Part No 03 (GC No 301 105)
5.5.12	Assemble the second small maintenance clip on the end of the inner flue tube.
5.5.13	Refit the flue elbow onto the boiler. Align the flue elbow with the flue pipe and tighten the maintenance clip between the flue elbow and the boiler.
5.5.14	Draw the flue pipe towards the boiler and tighten the second clip over the joint between the inner flue pipe and the flue elbow.
5.5.15	There must now be a gap of approximately 15mm from the elbow to the end of the outer tube.
5.5.16	Check also that the outer end of the flue projects as indicated in fig 12.
5.5.17	Referring to fig 10 fit the large maintenance clips into position and secure the clip screws.
5.5.18	Check adjust and tighten all supports.
5.5.19	Seal the peripheral gap around the outer tube with cement or mastic and slip the cosmetic flexible plastic collar (fig 12) item C) into groove on the pipe. This operation can only be carried out with external access.
	N.B. Absence of the collar will not affect operation of the appliance.
5.5.20	INSTALLING ONE OR TWO ADDITIONAL 90° FLUE BENDS Part No 02 (GC No 301 104)
5.5.21	Assemble the large and small maintenance clips as show in fig 13A
5.5.22	Carry out steps 5.5.2-5.5.3
5.5.23	Ensure when siting the flue hole position that the total length of the straight flue pipe used does not exceed the maximum permissable. 1 extra 90° bend and a maximum of 3.75 metres of straight flue. 2 extra 90° bends and
	metres of straight flue. 2 extra 90° bends and

5.5.24 Measure carefully the distance between the centre of the flue bend on the boiler to the centre of the hole through the wall (dimension X fig 13).
NOTE: Exension kit/s (Part No 026) will be required when using additional 90° bends.
5.5.25 Subtract 230mm from the measured dimension, separate the two tubes and cut the outer tube to this dimension.
.5.26 Cut the inner tube 15mm longer than the outer tube.
27 Reterring to fig 10 assemble a small maintenance clip on the outlet of the boiler flue bend. Push the inner flue tube into clip and tighten clip screws.
5.5.28 Slide the outer flue tube into place leaving approx. 15mm between the bend and the flue tube.
5.5.29 Referring to fig 10 fit the large maintenance clip into position and tighten clip screws. 5.5.30 Connect the flue tube to the extra bend using
the same method ensuring that the bend outlet is in line with the hole through the wall. 5.31 Ensure that the flue pipe runs parallel to the
.5.31 Ensure that the flue pipe runs parallel to the wall then carefully measure the distance from the outside face of the wall to the centre of the extra bend (dimension W fig 13).
.9.32 Subtract 9/ mm from the dimension and cut the outer tube to this length. NOTE: The two tubes must be separated by removing screw G fig 12 before cutting.
5.5.33 Ensure that any shortening of the tube is done from the plain end.
5.5.34 Reassemble the inner and outer flue tubes and refix screw G.
5.5.35 Mark the inner tube 7 mm longer than the outer and cut off the inner tube at this point.
5.5.36 Remove the large maintenance clip, loosen the small clip and remove the bend.
5.5.37 Push the flue tubes through the wall, loosely refit the extra flue bend.
5.5.38 Assemble a small maintenance clip onto the inner flue tube, draw the flue tube towards the flue bend until the inner tubes butt. Tighten the screws on the small clip
Referring to fig 10 fit the large maintenance clip into position and secure clip screws.
5.5.40 Check and adjust if necessary so that the
Tighten all maintenance clips, make sure that the entire flue is horizontal and adequately supported. Use at least one bracket (Part No 03, G.C. No 301 105) for each extension.

5.6 CONNECTING THE GAS AND WATER

5.6.1 Figs 8 and 14 show the locations of the fittings.
5.6.2 Do not over tighten nuts and use another spanner to apply counter force to avoid damaging the appliance.

5.6.3 GAS SUPPLY

Connecting the gas supply.

Connect a 15mm gas pipe to the gas service tap and tighten the union nut securing the

5.6.4 CENTRAL HEATING

Connect the central heating pipework (22mm o.d) to the respective valves, right hand = flow, left hand = return, and tighten the nuts.
5.6.5 SAFETY VALVE DISCHARGE The safety valve is located beneath the pump

It has a threaded outlet (Rc 1/2" BSP Ini) to permit a discharge pipe to be connected. When connecting, ensure the discharge pip

when connecting, ensure the discharge pipe does not restrict access to or operation of the central heating valves. The discharge should terminate facing downwards exterior to the building in a position where discharging (possible boiling) water will not create danger or nuisance; but in an easily visible position.

5.7 ELECTRICAL CONNECTIONS

The electricity supply must be as specified in clause 4.7. If controls external to the appliance are required design of the external electrical circuits should be undertaken by a competent person.

See section 10 for further electrical wiring details.

Factory fitted internal wiring must not be disturbed when wiring external controls N.B. IT IS ESSENTIAL THAT ALL EXTERNAL

N.B. IT IS ESSENTIAL THAT ALL EXTERNAL CONTROL CIRCUITS AND WIRING IS WIRED FROM THE SAME ELECTRICAL ISOLATOR AS SERVES THE APPLIANCE.
5.72 To gain access to the terminals release the 2 screws securing the outer control fascia (top corners)

Note these 2 screws and associated cup washers are not captive. Ensure they are not lost.

The panel is bottom hinged. Pull it forwards and downwards until it rests in an approximately horizontal position.

The terminal block is easily visible on the left hand side.

5.7.3 The electricity supply cable from the isolator and the Appliance terminal block must be 3 core flexible sized 0.75mm2 (24x0.2mm) to table 15-16 BS 6500.

Wiring to the Appliance should be rated for operation in contact with surfaces up to 90°C.

Pass the cable through the cord anchorage and connect it so that should the cable slip the anchorage the current carrying conductors become taut before the earthing
Securely tighten ail terminal screws and arrange the cable with slack between the anchor and the terminal block. Tighten the cord anchorage.
6 Neatly arrange the external cable in such a way that unrestricted opening of the controls fascia is possible without strain on the cable.
5.7.7 External controls may be wired from terminals 2 and 3 (after removing the factory fitted link). If a neutral is needed use terminal N.

If required pass this cable through the same cord anchorage.

The conductors should be so connected that the conductor to terminal 2 becomes taut before those to 3 or Earth (+) should the cable be strained.

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6.1 brackets, refer to figs. 1 and 2 unless Where the text bears identifying numbers in
described in BS 6891. meter, test for soundness and purge, all as GAS SUPPLY INSTALLATION

CENTRAL HEATING SYSTEM

6.3.1 6.3 IMPORTANT
expansion tank. It is charged with air at the

6.4.1 6.4

6.3.2 INITIAL FLUSHING OF THE PIPEWORK

6.3.2.1 from the system. It is recommended therefore be damaged or blocked by grease and dirt
Close the appliance central heating valves

clean water (for at least five minutes). the entire system until the drain discharges return and a drain pipe to the flow and flush connect a temporary water supply to the

reconnect the flow and return pipes to the Drain the system by opening the drain taps at all low points. Close the drain taps and

INITIAL FILLING OF THE SYSTEM

See Clause 3.4.4. and 4.6.8
Open central heating flow and return valves
Close all air release taps on central heating
6.3.3.4 Gradually open stopcock at the filling point until water is heard to flow. Do not open fully
Starting with the lowest radiator open each air release tap in turn closing it when clear

6.5.7

Continue tilling the system until at least 1.5bai registers on the gauge (11) then turn off the
inspect the system for water soundness and medy any leaks discovered.
1.0bar and a maximum of 1.5bar.

plus the height in metres to the highest poin
N.B. The safety valve is set to lift at 3 bars
6.3.4.3 (19) a quarter turn to release water until the

CHECKING ELECTRICITY SUPPLY

uarry out preliminary checks for earth g access as required according to
6.4.2

LIGHTING THE BOILER

6.5.1 6.5

(For access procedure turn off electricity and refer to clause 5.7.2 for instructions). may be easier if the external controls are If external controls are fitted (e.g. Timecloci heat. The commissioning of the appliance
6,5.2
6.5.3
6.5.4
6.5.5 sequence and the purner will light. The boiler will now go through an ignition
If during the ignition attempt period (10 seconds approx.) the boiler fails to light, the
completely purged of air and that gas is reaching the boiler then repeat from 6.5.2 gas supply. Check that the gas supply is most common cause of the boiler going to

6.6 CHECK BURNER PRESSURE

6.6.1 to check/adjust this when commissioning The heat input is factory set to the maximum
Refer to tig 15 to determine the pressure to he heating output you need (e.g. for 40,000 Fig. 15
6.6.2 access to the interior as instructed in clause

mba

pressure gauge. Turn on the boiler for centra (Fig 16) and slacken the screw half a turn in
6.6.4 data badge. This is to ensure that the burne (fig 1b) and adjust regulating screw underneath. Once this pressure has been fixed it should be indelibly recorded on the adjusted by removing regulator cover screw minus 1.0mbar/0.42in wg). If the pressure is

6.7 CHECKING THE FLUE SYSTEM

for soundness. Check all clamps and fixings

6.8 CHECKING THE HEATING THERMOSTAT

6.8.1 switches from 'on' to 'off' and vice versa (scale range covers approx. 45°C - 85°C) Allow the system to warm up and manipulate

6.9 REGULATING THE CENTRAL HEATING

6.9 are warm, remove any thermostatic valve run the appliance in the central heating mode until heated water is circulating. If conditions Fully open all radiators and circuit valves and
6.9.2 Intact circulating See cl 4.6.3 If the burner will not light, ensure that water is
6.9.3 Adjust radiator return valves and any branch circuit return valves until the individual return
6.9.4 when all is adjusted, progressively close all radiator valves to ensure that the appliance

system should be regulated to ensure a flow rate of at least 350 litres/hour (1.28 gals/min)

Page 9

6.10	FINAL FLUSHING OF THE HEATING SYSTEM	6.11.4	Check the appearance of the gas flame to assess adequacy of combustion air supply.
6.10.1	After the system has been thoroughly heated to about 60°C (140°F) or above, and hot water	6.11.5	Re-check the flue system for soundness and adequacy of supports.
	has circulated to all parts any residual grease, flux and other foreign material will have been dislodged.	6.12	CONCLUDING OPERATIONS
6.10.2	Inspect the system for soundness. Turn the appliance off and turn off the on/off switch (fig 1 22).	6.12.1	It external controls have been disconnected and terminals 2 and 3 temporarily linked remove the link and reconnect the external control circuit, check the operation of the
	Open all drain taps and quickly drain the system whilst still hot to remove offending		external controls.
	substances. Refill as instructed in clause
		6.13	REFIXING THE FRONT CASING.
6.11	FINAL CHECK FOR OPERATIONS	6.13.1	Offer up the front casing to the back frame in
6.11.1	Disconnect pressure gauge, retighten screw. Relight boiler.		a near vertical attitude and locate the nooks on the casing over the hooks on the frame. Slide the casing downwards to fully engage
6.11.2	Re-check for gas soundness.		the hooks and flex the bottom of the case
6.11.3	Re examine heating and hot water systems and cold water supply for water soundness.		outwards and push nome to aligh the bottom fixing holes. Replace the four case retaining screws.

SECTION 7 INSTRUCTING THE USER

71 Hand over the copy of the Users Instructions supplied together with this Installation book and explain how to operate the boiler correctly. Explain how to use the Timeclock and Boom Thermostat if fitted

7.5

72 Show the user how to switch off the appliance quickly and indicate the position c the electric supply isolator.
7.3 Explain that air supply grilles must not be blocked in any way.
7.4 Inform the user of the location of all drain cocks and air vents.
Explain how to turn the appliance off for both short and long periods and advise on the precautions necessary to prevent damage should the appliance be inoperative when freezing conditions may occur.
Finally, advise the User that, for continued safe and effective operation, the appliance must be serviced by a competent person at least once a year.

7.6

SECTION 8 SERVICING INSTRUCTIONS

8.1 GENERAL

To ensure efficient safe operation of the appliance it is necessary to carry out routin servicing at regular intervals.

The frequency of servicing will depend upon the particular installation conditions and the use to which the boiler is put; but, in general, once per year should be adequate. It is the law that any service work must be carried out by a competent person such as British Gas or other recognised companies.

The following instructions apply to the boiler and its controls, but it should be remembered that the central heating system will also require attention from time to time.

8.2 IMPORTANT NOTES

WARNING: Having carried out preliminary flame checks and before starting any servicing work, switch OFF the mains electricity supply and disconnect the plug at the main isolating switch and socket. (If a switch is used remove the fuse.)

Turn off gas supply at the gas service tap fitted to the appliance.

Always test for gas soundness after any service work and after exchanging any gas carrying component.

.3 RECOMMENDED ROUTINE SERVICING .3.1 ANNUAL SERVICING

The following procedures should be carrie out at least once per year.

Inspect exterior for signs of damage and deterioration particularly of flue pipework and electrical connections.
Inspect air supply and ventilation arrangements comparing them with the requirements laid down in clauses 4.5.1 2 to ensure no alterations have been
Turn off mains electricity and remove front casing (see clause 8.4).
Replace fuse if previously removed (8.: above) and turn on electricity, run the boiler for a few minutes to permit inspection of its operation, inspect the burner for yellowing of flame tip, flame lift off or sooting.

Ensure central heating valves (fig 1) are open. Note these are 1/4 turn valves which are open when handle is vertical, closed when handle is horizontal. Observe pressure gauge reading (fig 1 no. 11) which should be approximately 1 bar when the system is cold (see clause 6.3.4)
Turn off mains electricity and turn off gas service tap on the appliance.
Gain general access as described below in clause 8.4.
Lightly clean with a soft brush and Lightly clean with a soft brush and inspect for damage. If during initial inspection, any combustion irregularity was suspected, remove injectors and clean or replace (see clauses 8.6 and
Place cloth below combustion chamber to catch debris. Clean heat exchanger using suitable brushes and rods if necessary.
Inspect combustion chamber lining. The insulating material is easily damaged. Do not scrape, but clean off lightly.
If any panels are damaged these should be replaced (see Clause 8.11).
Heplace all parts in reverse order but leave the controls fascia open and outer casing off.
Undertake a complete commissioning check as detailed in section 6.
13. Close up and secure control fascia and
14. Clean off casing using soft cloth and dilute detergent.

8.3.2 REPLACEMENT OF PARTS

The life of individual components varies and they will need servicing as and when faults develop. The fault finding sequence charts in section 9 will serve to locate which component is the cause of any malfunction, and instructions for removal, inspection and replacement of the individual parts are given in the following pages.

Page 10

To remove components access to the interior is essential. Refer to figs 17 & 18

Fig

8.4.1 To remove front casing Flex out base of casing and pull bottom or
8.4.2 17) at the top of the fascia and swing down lo open control fascia release 2 screws (fig
8.4.3 plastic grill downwards
COVER (including viewing window) Part No 5957 COM SEALED CHAMBER FRONT

8.5

8.5.1 eter to fig 19
8.5.2 Remove roomsealed front cover plate by releasing six screws (fig 19) and easing cover off. The screws are not captive. inspect gasket for damage. If damaged, replace.

Fig. 18

SENSING ELECTRODES MAIN BURNER AND/OR SPARK AND

Pefer to figs 20,21 & 22
8.6.1 Gain general access as 8.4
8.6.3 8.6.2 Remove front of combustion chamber by Remove room-sealed front cover as 8.5.2
8.6.4
8.6.5 Release electrode retaining screws and carefully remove electrodes (fig 22).
8.6.6 control and disconnect.
8.6.8 8.6.7
Remove main burner. Reassemble in reverse arder ensuring correct location of electrodes

MAIN BURNER INJECTORS

8.7 8.7.1
8.7.3 8.7.2 Remove room-sealed front cover as 8.5.2
Remove front of combustion champer as
8.7.5 8.7.4

Page 11


	Reassemble in reverse order. See fig 38 for correct fitting of electrical connections. The air pipe must be reconnected to the upper nozzle on the pressure switch.	8.10.6
	Pull off tab connectors and ease pressure switch upwards, disconnecting air pressure pipe in the process.	8.10.5
	Pull air tube from nozzle on inner flue bend.	8.10.4
	Remove 3 screws holding pressure differential switch cover (fig 24) and remove cover.	8.10.3
	Remove room-sealed front cover plate as 8.5.2	8.10.2
	Gain general access as 8.4	8.10.1
	FLUE PRESSURE DIFFERENTIAL SWITCH Part No 5926 Refer to fig 24	8.10
	Reassemble in reverse order, replacing centre screw first.	8.9.9
	Unscrew 3 screws retaining fan to flue hood and remove fan. Transfer aluminium manifold (2 screws) to new fan.	8.9.8
	Carefully slide flue hood forward disconnecting electrical leads on fan in the process.	8.9.7
	Remove 3 flue hood retaining screws (fig 24)	8.9.6
	Remove silicone pipe from nozzle on inner flue bend.	8.9.5
	Unscrew maintenance clip securing screws and remove clip (fig 24)	8.9.4
	Remove front of combustion chamber as 8.6.3	8.9.3
	Remove room-sealed front cover plate as 8.5.2	8.9.2
Sei	Gain general access as 8.4	8.9.1
Тe	FLUE FAN Part No 5963	8.9
	Reassemble in reverse order using new fibre washers on both unions.	8.8.8
	Carefully slide out heat exchanger avoid spillage of water on boiler electric's.	8.8.7
	Unscrew unions on both sides.	8.8.6
	Place cloth under heat exchanger to catch surplus water.	8.8.5
	Close heating valves (1/4 turn until handle is horizontal). Turn safety valve 1/4 turn to drain primary circuit of boiler.	8.8.4
	Remove front of combustion chamber as 8.6.3	8.8.3
_	Remove room-sealed front cover plate as 8.5.2	8,8,2
	Gain general access as 8.4	8.8.1
	MAIN HEAT EXCHANGER Part No 5388 Refer to fig 23	8.8

COMBUSTION CHAMBER INSULATION

Gain general access as 8.4

8.13.1

GAS CONTROL VALVE COMPLETE

Remove main heat exchanger 8.8
Io remove rear board, gently prise upward
8.11.5

8.13.5

Remove 2 screws securing gas valve bracket Remove 4 flange securing screws at lower

end. Undo union at top of supply to burner.

vaive to retain regulation settings.

Remove servo pressure regulato: Clause 8.12.5.

urn off gas supply. Disconnect 2 earth leads. Pull off all electrical connections

Refer to figs 25, 26 & 27 GAS CONTROL VALVE, OPERATOR AND SOLENOID.

Check burner pressure (cl 6.6)

Fig. 25

lest all joints for gas soundness

SERVO PRESSURE REGULATOR lurn off gas service tap.
connectors, also remove earthing tags.

Hegulator

Remove module and rubber diaphragm from
8.12.7 Caretully place new rubber diaphragm in position on valve body and fit replacement diaphragm

Hegulato

Replace 2 screws and tighten
Reassemble in reverse order. See fig 38 for
SOLENOID
Hefer to fig 27
Pull off electrical leads from solenoid.
Remove the spring blade retaining clip
Pull off the 'C' bracket and coil assembly
Place new coil in 'C' bracket and slide the
Push the retaining clip back into position and check that bottom of clip has engaged
See fig 38 for electrical connections

Page 12

8.14.1

(A) COMPLETE PUMP

8.14.4 connection is around right hand side of gas eft corner of combustion chamber. Pull pipe
8.14.6

(B) PUMP HEAD ONLY

8.14.7 Unscrew four Allen screws, withdraw head

electrical leads. Brown to L, Blue to N

8.15

Remove retaining screw (securing manifold rieating valve unions.
pressure gauge connection and heating flow
8.15.5

MANIFOLD ASSEMBLY

Release cover retaining screws and ease of

Refer to tig 29 for location of components

CHECKING/REPLACING MAIN

to 1 bar (14,7ps) and should be checked during servicing. Should it have lost pressure it can be repressurised in situ. Drain the bolian Ett and itable some not account of the
sening the upper vessel retaining screw

vessel will require changing. Alternatively, a

8.16.11 expansion vessel in situ. follow steps 8.16.10 above of 343mm (13.5in) or more and with a N.B. If the boiler is installed with a clearance

Gain access as 8.4
Drain appliance via safety valve by 1/4 turn
Remove screws on large maintenance clips
Disconnect electricity supply at p.c.b. (read
Disconnect expansion pipe at heating manifold, lift vessel & pipe out of

Fig. 30

Reassemble in reverse order

spot)

Refer to figs 32 & 28

(3) lift vessel and pipe

heating expansion vessel behind combustio chamber

SAFETY VALVE

uain General Access 8.4
horizontal). Turn safety valve 1/4 turn to drain heating valves (1/4 turn until handle is
Hemove Heating Microswitch as 8.18.2.

REMOVAL OF ELECTRICAL COMPONENTS

nect pipe at this enc

isolator and gain general access (8.4)
HEATING MICRO SWITCH Refer to fig 29

8.18.2

8.18.3
8.18.4
8.18.7
HIGH LIMIT THERMOSTAT Part No 3409 Refer to fig 32
Gain general access 8.4
Remove room-sealed front cover 8.5.2
retaining nut.
Clips

Page 13

SECTION 9
OPERATIONAL (
CHECKS,
WIRING DIAGRAMS & FAULT F
INDING

8.18.18 HEATING THERMOSTAT
Remove room-sealed front cover 8.5.2
retaining clip, remove sensor from pocket
8.18.23 Pull electrical tabs off back of thermostat
thermostat and push-on wiring tabs. Reassemble in reverse order referring to figs
ELECTRONIC IGNITION CONTROLLER
8.18.28 Pull of cable connector and ignitor lead. Gain general access as 8.4
SWITCHES ON/OFF and TIMED/REST/ CONSTANT or MODE SELECTOR
8.18.32 latching tabs at the back of the panel and
To replace refer to fig 34 to ensure switch is the front until spring tabs latch. Refer to fig
Fig. 32 Control Gauge Spare Hg. 33 White

Part No 4931

FAN OVER-RUN THERMOSTAT

REMOVAL OF MECHANIC/
INSTRUMENTS AND COMPONENTS
Close central heating flow and return valves by 1/4 turn to horizontal position, drain
Trace capillary from back of gauge to
and press gauge from apenure
TEMPERATURE GAUGE
retaining clips and remove sensor. Trace capillary to sensor. Hemove sensor
and press gauge from aperture.
8.19.11 Reassemble in reverse order following
Run through the general commissioning as described in Section 6 as far as they apply. END OF SERVICING

8.20

9.1 remaking of electrical connections the checks Earth Continuity, polarity and

I he tollowing tlow diagrams suggest the logical sequence of steps for fault finding.

installer or service engineer.

role of each part is briefly described included for reference. As further help, the

provides an alternative suppy to the fan,

If the supply to P1 is broken (e.g. by a room

P1-1 breaks the boiler circuitry will go to rest

energised and the sparking will stop. To reset the boiler after lockout turn off the boiler on/ At which time the gas valve will be de

ignition attempt periou)

If a flame is not detected the boiler will go to

When tollowing this sequence, reter to tigs 36 & 38. It is assumed that the on/off switch

boiler to below 350 litres/hour (1.28 gpm) the boiler flow switch will open and de-energise the fan which in turn shuts down the boiler.

and safety thermostats will energise termina At the same time a supply through the boiler control thermostat (P1-1) via the high limit

and then in turn to the normally closed his supply is connected internally to termina

upply to terminal 10

remove the supply from the fan, allowing it to

energising it's normally open contact (pin 2 This supply is fed via the boiler flow switch to ressure differential switch to change over

gas valve being energised and the electrode I here will be a short delay, tollowed by the

attempt time (8-12 seconds) the sparking

12-48 Mynute

Temperatur

Page 14

FAULT FINDING STEP 1 CHECK ELECTRICAL SUPPLIES, SWITCHES & CONNECTIONS

Proceed to Next Step

FAULT FINDING STEP 2 CHECKING C/H THERMOSTAT CIRCUIT

NOTE 1 Reduce number of radiators on to give quick response.

12-48 R.S.E. MYNUTE

Page 15

FAULT FINDING STEP 3

18 Mynute

Page 16

ğ (A) Fitting Vokera 24 Hour Time Switch (Part No. 032 GC No. 301 110) and Fitting Vokera Digital 7 Day Time Switch (Part No. 05 G.C. No. 301 109) (B) Wiring to external Time Switches, Room Thermostats and

rost inermos

Installation of the Vokera Time Switches (24 Hr and 7 Day)

Remove the clock aperture blanking plate (1) (fig 1) by squeezing the two lugs on the rear of the plate together and push the plate out.

crews provided. (fig. 2). panel. Push the mounting bezel (2) through the

nect the other ends of the wires to the main inal block as detailed below. (fig. 3).

THILD I. d/White: Push on to spare spade connector on

Blue: Connect to terminal marked 'N'

Red / Black: Connect to spare terminal o

White: Connect to terminal 2 on main terminal block. (leave link 2-3 connected if no room thermostat is

Hemove the loop between terminals 2 & 3 on the boiler terminal block, if a room stat is also fitted.

12-48 Mynute

Page 17

(i) 'Y' Plan

N ω

C. Wiring to 'Y' plan or 'S' plan installations

Page 18

12-48 Mynute

Fig. 35b Outer Casing

Fig. 35c Cover and Left-Right Sides

Page 19

12-48 Mynute

3409 4250 4254

0598 0602

0557

493

SHORT SPARE PARTS LIST

Code

G.C. No

Description

- 5811 - 5143

Fig. 35m Front Panel

Page 20

12-48 Mynute

Vokera 12-48 RSE Mynute INSTALLATION AND SERVICING INSTRUCTIONS

SECTION 1 INTRODUCTION

SECTION 2 DESIGN PRINCIPLES AND OPERATING SEQUENCE

CENTRAL HEATING

2.3

2.3.1

з.1 UNITS

Height: 880mm (34.5in) overall DIMENSIONS AND CONTENTS

ა ა CONNECTION SIZES

3.4

3.4.1

Fig. 3

ω 5 ELECTRICAL DETAILS

3.6 PERFORMANCE

Main Burner Injectors 7 x 1.35 Main Burner: Polidoro BURNER DETAILS type NP7

SECTION 4 GENERAL REQUIREMENTS

GENERAL REQUIREMENTS

RELATED DOCUMENTS

GAS SUPPLY

LOCATION OF APPLIANCE

FLUE SYSTEM

TERMINAL POSITION FOR FAN ASSISTED BOILER

4.5

WATER CIRCULATION

4.6.2 FIFEWORK

4.6.3

4.6.4 Figs 5&6 illustrate typical heating only layouts, but the boiler is also suitable for installation with a 'Yor'S' plan system. SYSTEM DESIGN

4.6.5 DRAINING TAPS

AIR RELEASE POINTS

4.6.8 FILLING POINT

4.7 ELECTRICAL SUPPLY

UNPACKING

0.3 PREPARING FOR MOUNTING

5.5 5.5.1 FITTING THE FLUE

off inner tube is 890 - 630 = 260.

5.6 CONNECTING THE GAS AND WATER

5.6.3 GAS SUPPLY

Connecting the gas supply.

5.6.4 CENTRAL HEATING

5.7 ELECTRICAL CONNECTIONS

CENTRAL HEATING SYSTEM

6.3.2 INITIAL FLUSHING OF THE PIPEWORK

INITIAL FILLING OF THE SYSTEM

CHECKING ELECTRICITY SUPPLY

LIGHTING THE BOILER

6.6 CHECK BURNER PRESSURE

6.7 CHECKING THE FLUE SYSTEM

6.8 CHECKING THE HEATING THERMOSTAT

6.9 REGULATING THE CENTRAL HEATING

SECTION 7 INSTRUCTING THE USER

SECTION 8 SERVICING INSTRUCTIONS

8.1 GENERAL

8.2 IMPORTANT NOTES

8.3.2 REPLACEMENT OF PARTS

SENSING ELECTRODES MAIN BURNER AND/OR SPARK AND

MAIN BURNER INJECTORS

COMBUSTION CHAMBER INSULATION

(A) COMPLETE PUMP

(B) PUMP HEAD ONLY

8.15

MANIFOLD ASSEMBLY

CHECKING/REPLACING MAIN

SAFETY VALVE

REMOVAL OF ELECTRICAL COMPONENTS

Installation of the Vokera Time Switches (24 Hr and 7 Day)

SHORT SPARE PARTS LIST