Saunier duval THEMA F SB 23 E, THEMA F SB 18 E User Manual

Heating and hot water for the professionals

Installation and Servicing Instructions

THEMA F

IN WARRANTY

THIS IS A CAT II2H3+ APPLIANCE

TECHNICAL HELPLINE

01773 828400

01773 828100

1

INSTALLATION AND SERVICING INSTRUCTIONS

THEMA F 23 E - THEMA F SB 18 E - THEMA F SB 23 E

Note!

The boiler serial number is marked on the label attached to the inside of the boiler. Refer to the

'Introduction' section page 3 for a description of the basic functions of the boiler. To safely operate

the boiler, refer to the Users Instructions.

INSTALLATION SECTION

Introduction.................................................. Page 3

Dimensions ............................................................. 3

Technical data ................................................. 4 - 5

Boiler schematic .................................................... 6

Fixing jig .................................................................. 7

Domestic hot water system design..................... 7

Heating system design ......................................... 8

Piping system installation...................................... 8

Boiler location ........................................................ 9

Boiler installation .................................................. 10

Rear outlet flue installation ......................... 11 - 12

Top outlet flue installation .................................. 13

Electrical connection ......................................... 14

Commissioning ............................................. 15 - 16

Safety devices ..................................................... 16

Settings.................................................................. 17

Changing gas type ............................................. 17

SERVICING SECTION

Routine cleaning and inspection .... Page 18 - 19

Replacement of parts ................................. 19 - 24

Microswitch assembly ......................................... 19

Fan ......................................................................... 19

Air pressure switch ............................................... 19

Spark generator................................................... 19

Main printed circuit board ................................. 19

Ignition printed circuit board............................. 20

Pump ..................................................................... 20

Temperature/Pressure gauge............................ 20

Reversing valve assembly .................................. 20

Reversing valve front section ............................ 21

Loss of water switch ............................................ 21

Water valve or diaphragm ................................ 21

Gas valve ............................................................. 22

Modulating coil ................................................... 22

Central heating safety valve ............................. 23

Heat exchanger .................................................. 23

Expansion vessel .................................................. 23

Boiler thermistor ................................................... 23

Overheat thermostat .......................................... 24

Combustion chamber insulation....................... 24

Ignition electrode ................................................ 24

Flame sense electrode ....................................... 24

Burner .................................................................... 24

Burner injectors .................................................... 24

Timeclock ............................................................. 24

Schematic wiring diagram ................................ 25

Fault finding................................................... 26 - 27

Spare parts ........................................................... 27

Mandatory warning notice for CEE countries

UK

WARNING, this appliance is designed, approved and inspected to meet the requirements of the

English market. The identification plate located on the inside of the appliance certifies the origin where the
product was manufactured and the country for which it is intended.
If you see any exception to this rule, please contact your nearest Saunier Duval dealer.
Thank you in advance for you assistance.

2

INTRODUCTION

The THEMA F 23 E boiler is a wall mounted modulat­ing combination boiler with electronic ignition pro­viding central heating and instantaneous domes­tic hot water.
Both the central heating and domestic hot water
temperature are user adjustable from the boiler
control panel.
Domestic hot water demand always has priority
over heating demand.

The

THEMA F SB 18 E and SB 23 E

mounted modulating boilers with electronic igni­tion providing central heating only.
The central heating temperature is user adjustable
from the boiler control panel.

The boilers are of the II2H3+ category for use with
Natural Gas (G20) as distributed in the United King­dom, or with Butane or Propane gas (G30/G31) with
the appropriate conversion kit.

Conversion kits:

Conversion Part No.
Natural Gas (G20) to G30/G31 86161

Boilers burning LPG or similar gases MUST NOT be
fitted in basements or below ground level.

The boiler has a fan assisted balanced flue which
both discharges the products of combustion to and
draws the combustion air from the outside air.

boilers are wall

The boiler is supplied for rear outlet flue connec­tion. Alternatively, the boiler is designed to allow
the flue system to be connected to the top of the
boiler, top outlet flue connection. Refer to the flue
fitting instructions.

Electrical components have been tested to meet
the equivalent requirements of BEAB.

The boiler is designed for use as part of a sealed
water central heating system with fully pumped
circulation. The pump, expansion vessel and asso­ciated safety devices are all fitted within the boiler.

The boiler can be installed against either an exter­nal wall or on an adjacent inside wall, that is, the
flue system will pass directly to the rear or to either
side to the terminal fitted on the outside wall face.

The installation must be carried out by a compe­tent person in accordance with the relevant re­quirements of The Building Regulations, The Water
Byelaws, The Building Standards (Scotland) Regu­lations and any applicable local regulations.

Ancillary equipment

A range of flue accessories are available includ­ing vertical flues, twin-pipe flues, bends etc.
For further information contact your supplier.

Diagram 1

THEMA F 23 E

DIMENSIONS

Diagram 2

The boiler is delivered in three
separate packages:

- The boiler

- The fixing jig

- The flue system

Net weight: 41 kg
Gross weight : 43 kg

THEMA SB 18 E and SB 23 E

234

802

623

857

410

378

Hab 271a

3

TECHNICAL DATA

THEMA F 23 E

THEMA F SB 18 E

Heating output automatically variable from (kW) 8,9 8,9 8,9

Efficiency (%) 91,5 90,5 91,5
Heating adjustment 38°C to 90°C
Expansion vessel effective capacity (l) 6,5 6,5 6,5
Expansion vessel charge pressure (bar) 0,5 0,5 0,5
Maximum system capacity at 75°C (l) 160 160 160
Safety valve, maximum service pressure (bar) 3 3 3
Products outlet diameter ( mm) 60 60 60
Fresh air inlet diameter (mm) 100 100 100

Hot water output automatically variable from (kW) 8,9 — —

Maximum hot water temperature (°C) 65 — —
Specific flow rate (for 30°C temp rise) ( l/min) 9,6 — —
Threshold flow rate (l/min) 3 — —
Nominal water flow rate (l/min) 12 — —
Maximum supply pressure (bar) 10 — —
Minimum operating pressure (bar) 0,5 — —

Electrical supply (V) 230 230 230
Maximum absorbed power (W 150 150 150

(BTU/H) 30,000 30,000 30,000

to (kW) 23,3 18,5 23,3

(BTU/H) 80,000 63,000 80,000

(BTU/H) 30,000 — —

to (kW) 23,3 — —

(BTU/H) 80,000 — —

THEMA F SB 23 E

Burner injector mm 1,20 1,20 1,20
Inlet pressure mbar 20 20 20
Diaphragme mm — — —

(G20)

Gas rate (maximum) m3/h 2,70 2,17 2,70

Natural Gas

Butane

Propane

Town gas

Gas rate (minimum) m3/h 1,13 1,13 1,13
Burner injector mm 0,73 0,73 0,73
Inlet pressure mbar 29 29 29
Diaphragme mm 4,8 3,2 4,8

(G30)

Gas rate (maximum) kg/h 2,01 1,62 2,01
Gas rate (minimum) kg/h 1,13 1,13 1,13
Burner injector mm 0,73 0,73 0,73
Inlet pressure mbar 37 37 37
Diaphragme mm 4,8 3,2 4,8

(G31)

Gas rate (maximum) kg/h 1,98 1,60 1,98
Gas rate (minimum) kg/h 0,97 0,97 0,97
Burner injector mm 2,4 2,4 2,4
Inlet pressure mbar 8 8 8
Diaphragme mm — — —

(G130)

Gas rate (maximum) m3/h 3,88 3,88
Gas rate (minimum) m3/h 1,63 1,63 1,63

4

TECHNICAL DATA

Pressure table :

(kW) 8,9 10 11 12 13 14 15 16 17 18 19 20 21 22 23,3

(Btu/h) 30387 34142 37557 40971 44385 47799 51214 54628 58042 61456 64871 68285 71699 75113 79552

(kW) 11,9 13,2 14,4 15,7 16,9 18,1 19,2 20,4 21,5 22,7 23,8 24,9 26,0 26,9 28,3

(Btu/h) 40678 45130 49332 53481 57579 61627 65626 69575 73477 77333 81142 84906 88913 91713 96602

GAS

G 20 (mbar) 1,3 2,1 2,6 3,0 3,5 4,0 4,5 5,1 5,7 6,3 6,9 7,6 8,3 8,8 9,8
G 30 (mbar) 3,7 5,3 6,3 7,4 8,6 9,8 11,1 12,5 13,9 15,5 17,0 18,6 20,4 21,7 24,1
G 31 (mbar) 4,0 6,3 7,5 8,8 10,2 11,7 13,3 14,9 17,2 20,1 20,3 22,2 24,4 26,0 28,8

Pump :

The performance of the pump varies according to the pump bypass setting, see diagram 3.

Heat output

Heat input

50

40

30

flow and return

20

10

Available pressure (kPa) between heating

0

(10 kPa = 1 m WG)

Diagram 3

Bypass fully shut

1

Open 1/4 turn

2

1

2

3

4

5

Pom 052

500 1000

Flow rate through heating system (I/h)

Open 1/2 turn

3
4

Open 1 turn

5

Open 2 turns

5

BOILER SCHEMATIC

3-Ignition module
4-Heating temperature adjuster
5-Hot water temperature adjuster
6-Temperature/ressure gauge
8-Expansion vessel

9-Pump
10 - Automatic air vent
11 - Burner
12 - Heat exchanger bleed pipe
13 - Heatexchanger
14 - Gas valve
16 - Heating and hot water thermistor
17 - Ignition electrode
19 - Overheat thermostat
20 - Flame sense electrode
21 - Loss of water pressure switch
22 - Fan
23 - Air pressure switch
24 - Gas cock

THEMA F 23 E

23

13

20

12

11

10

9

22

19

17

16

14

A - Heating return

B - Cold water inlet
C - Heating flow
D - Domestic hot water flow

E - Gas supply

THEMA F SB 18 E - THEMA F SB 23 E

3-Ignition module

4-Heating temperature adjuster

6-Temperature/pressure gauge

8-Expansion vessel

9-Pump

10 - Automatic air vent
11 - Burner
12 - Heat exchanger bleed pipe
13 - Heatexchanger
14 - Gas valve
16 - Heating and hot water thermistor
17 - Ignition electrode
19 - Overheat thermostat
20 - Flame sense electrode
21 - Loss of water pressure switch
22 - Fan
23 - Air pressure switch
24 - Gas cock

21

23

13

12

11

10

8

6

AB C

D

E

3

5

4

24

22

19

17

16

A - Heating return

B - Cold water inlet

C - Heating flow
D - Domestic hot water flow

E - Gas supply

Diagram 4

6

21

9

8

6

ACE

14

3

4

24

Shy 131

FIXING JIG

THEMA F 23 E

From left to right, the fixing jig comprises:
A - Heating return with isolating valve (m).
B - Cold water inlet with isolating valve (p).
C - Heating flow with isolating valve (q),

drain screw (r) and safety valve (s).
D - Domestic hot water out.
E - Gas service cock.

m

2

1

A

B

THEMA F SB 18
THEMA F SB 23 E

From left to right, the fixing jig comprises:
A - Heating return with isolating valve (m).
C - Heating flow with isolating valve (q),

drain screw (r) and safety valve (s).

E - Gas service cock.

4

3

C

D

55

113

p

r

5

113

q

6

E

s

7

23

34

23

55

57,5

25

33

Filters and washers :

1 - Washer
2 - Metal filter
3 - Flow regulator
4 - Plastic filter
5, 6 & 7 - Washers

57,5

110

Pla 105c

m

2

1

A

C

Diagram 5

p

r

5

q

s

7

E

DOMESTIC HOT WATER SYSTEM DESIGN

• Copper tubing or plastic Hep2 O may be used
for the domestic hot water system. Unnecessary
pressure losses should be avoided.

• The boiler may operate with a minimum supply
pressure of 0,3 bar but under a reduced flow rate.
Optimum performance will be obtained from a
supply pressure of 1 bar.

• The flow restrictor must be fitted in the cold wa­ter inlet during installation. This limits the flow through
the boiler to a maximum of 12 l/min.

25

115

23

Pla 116b

7

HEATING SYSTEM DESIGN

• The THEMA F boiler is compatible with any type of
installation.

• Heating surfaces may consist of radiators, convec­tors or fan assisted convectors.

• Pipe sectional areas shall be determined in accord­ance with normal practices, using the output/pres­sure curve (diagram 3). The distribution system shall
be calculated in accordance with the output require­ments of the actual system, not the maximum output
of the boiler. However, provision shall be made to
ensure sufficient flow so that the temperature differ­ence between the flow and return pipes be less than
or equal to 20°C. The minimum flow is 500 l/h.

• The piping system shall be routed so as to avoid
any air pockets and facilitate permanent venting of
the installation. Bleed fittings shall be provided at
every high point of the system and on all radiators.

• The total volume of water permitted for the heat­ing system depends, amongst other things, on the
static head in the cold condition.
The expansion vessel on the boiler is pressurised at 1
bar (corresponding to a static head of 5 m w.g.) and
allows a maximum system volume of 140 litres for an
average temperature of 75°C and a maximum serv­ice pressure of 3 bar. This pressure setting can be modi­fied at commissioning stage if the static head differs.

An additional expansion vessel can be fitted to the
system if required, see diagram 6.

• Provision shall be made for a drain valve at the
lowest point of the system.

• Where thermostatic radiator valves are fitted, not
all radiators must be fitted with this type of valve, and
in particular, where the room thermostat is installed.

• In the case of an existing installation, it is ESSENTIAL
that the system is thoroughly flushed prior to installing
the new boiler using a proprietary product such as
Fernox or Sentinel. Contact the product manufac­turers for specific details.

Filling the system

Provision must be made for filling the system at low
level. The use of a WRC approved filling loop is strongly
recommended, connected as shown in diagram 6.

PIPING SYSTEM INSTALLATION

• Heating system connections - Pipe diam 22 mm

• Hot water system connections - Pipe diam 15 mm

• Gas connection - Pipe diam 22 mm

• Safety valve discharge - Pipe diam 15 mm

Water connection

Connect the water pipes to the fixing jig using the
copper tails supplied, see diagram 5.
Warning: To prevent damage to the isolating cocks,
do not solder joints or fittings with the copper tails
connected.
Connect the system pipework to the boiler observ­ing the correct flow and return format as shown in

diagram 6.

Additional
expansion
vessel
(if required)

Return

Heating
circuit

Diagram 6

Flow

control valve

Boiler

Minimum 22 mm diameter

Bypass

valve

Drain point

Tundish
(supplied)

Filling point

Domestic

water

Hot

Cold supply

Pressure
reducing
valve
(supplied)

Sch 173

Safety valve discharge
WARNING. It must not discharge above an en-

trance or window or any type of public access
area.
Connect the safety valve discharge pipe to the
boiler, the discharge must be extended using not
less than 15 m o.d. pipe, to discharge in a visible
position outside the building, facing downward
preferably over a drain. The pipe must have a con­tinuous fall and be routed to a position so that any
discharge of water, possibly boiling or steam, can­not create any danger to persons, damage to
property or external electrical components and
wiring. Tighten all pipe connection joints.

Gas connection

• The supply from the governed gas meter must
be of adequate size to provide a constant inlet
working pressure of 20 mbar (8 in w.g.).
To avoid low gas pressure problems, it is recom­mended that the gas supply is connected using 22
mm pipe.

• On completion, the gas installation must be
tested using the pressure drop method and purged
in accordance with the current issue of BS6891.

Gas Safety (Installation and Use) Regulations

In your interests and that of gas safety, it is the law
that ALL gas appliances are installed and serviced
by a competent person in accordance with the
above regulations.

8

BOILER LOCATION

Clearances

The position of the boiler must be such that there is
adequate space for servicing.
The recommended clearances are:
40 mm either side of the boiler.
600 mm at the front of the boiler.
300 mm below the boiler.

Fixing jig

The fixing jig comprises three parts:

1) The connecting plate which allows the connec­tion and soundness testing of all the pipework be­fore the boiler is fitted and helps support the weight
of the boiler.

2) The hook which supports the weight of the boiler.

3) The template which ensures the hook and con-

necting plate are correctly fitted relative to one
another.

• Place template on wall in required position, mak­ing allowances for the necessary clearances etc.,

see diagram 7.
Note: It is permissible to install the boiler with re-

duced clearances at the bottom and sides of the
boiler PROVIDING that adequate consideration is
given for Servicing/Repairs at a later date. If any
doubt exists, contact the Saunier Duval Technical

Helpline 01773 828400.

• Mark the position of the holes for the hook and
connecting plate.

• Drill, plug and fix the connecting plate and hook
to the wall using suitable screws.

• Check that both the hook and connecting plate
are level.

If the boiler is not installed immediately, protect the
various couplings to prevent any ingress of foreign
materials e.g. plaster, paint etc.

Terminal position

The minimum acceptable spacings from the ter­minal to obstructions and ventilation openings are
shown in diagram 8.

255 mini

234

29

Diagram 7

60

50

mini

The boiler must be installed so that the terminal is
exposed to the external air.
Note: Under certain weather conditions the flue
may produce a plume of condensation, this is quite
normal.
If the terminal is fitted within 850mm of a plastic or
painted gutter or 450m of painted eaves, an alu­minium shield of a minimum length of 750mm
should be fitted to the underside of the gutter or
painted surface.

Should any doubt exist as to the permissible posi­tion of the terminal, contact the Saunier Duval

Technical Helpline 01773 828400.

Cupboard or compartment ventilation

The boiler can be fitted in a cupboard or compart­ment without need for permanent ventilation.

Ins 012a

Minimum dimensions (in mm) for the positioning of flue terminals

A-Under a window ................................................. 300

B-Under an air vent ................................................ 300

C-Under a gutter ....................................................... 75

D-Under a balcony.................................................300

E-From an adjacent window ................................300

F-From an adjacent air vent.................................300

G-From vertical drain pipes or soil pipes ..................75

H-From an external corner of the building .......... 300

I-From an internal corner of the building ........... 300

L-From the ground or from another floor ............ 300

M-Between two terminals vertically ....................1500

N-Between two terminals horizontally .................. 300

Diagram. 8

G

C

N

E

F

M

A

B

D

I

H

L

Ven 060b

9

BOILER INSTALLATION

Statutory requirements

The installation of this boiler must be carried out by
a competent person in accordance with the rel­evant requirements of the current issue of:

The Gas Safety (Installation and Use) Regulations
The Building Regulations
The local water company Byelaws
The Building Standards Regulations (Scotland)
The Health and Safety at Work Act

Sheet metal parts

WARNING. When installing or servicing this boiler,
care should be taken when handling the edges of
sheet metal parts to avoid the possibility of personal
injury.

Diagram. 9

Installing the boiler

Prior to starting work, the system must be thoroughly
flushed so as to eliminate any foreign bodies and
contaminants such as filings, solder particles, oil,
grease etc.
Note. Solvent products could cause damage to the
system.
Note. If using a rear outlet flue system, follow the
instructions in 'Rear outlet flue installation' section
prior to hanging the boiler.

• Engage boiler upper part onto the hook, see dia-

gram 9.

• Allow the boiler to seat down onto support plate,

see diagram 10.

• Fit filter and washers, strictly adhering to the se­quential order and directions shown on diagram 5.

• Connect the various couplings between the
boiler and the connection plate.

Diagram. 10

➞

Ins 020

REAR OUTLET FLUE INSTALLATION

The boiler is supplied for rear outlet flue connec­tion.
Alternatively, the boiler is designed to allow the flue
system to be connected to the top of the boiler,
top outlet flue connection.
For top outlet flue connection, refer to 'Top outlet

flue installation'

Rear outlet flue - kit 86151

The rear outlet flue system consists of two parts, a
white painted outer pipe and an aluminium inner,
they are positively locked together when assem­bled.

The flue kit 86151, see diagram 11, is 1000 mm long
and comprises:

- Outer pipe ........................................................... A

- Inner pipe ............................................................. B

- External rubber sealing collar ........................... C

- Flue elbow............................................................ D

- Internal flange ......................................................E

- 'O' rings ..................................................................F

- Screws ................................................................... G

- Rubber collar ....................................................... H

- Clamp and seal ....................................................I

- Gasket ................................................................... J

➞

A - Direct rear outlet flue

Mark correct position of hole from template using
hole between hook and connecting plate.

Diagram 11

A

B

G

I

C

H

E

D F

J

Ins 021

Pho 422

10

REAR OUTLET FLUE INSTALLATION

e

a

X

B - Rear outlet side flue

Mark the horizontal centre line on the rear wall.
Extend the horizontal centre line to the side wall
and mark the vertical centre line of the flue hole
as shown in diagram 12.

255 mini

Important: When cutting the flue hole and when
extending the flue centre line to a side wall, remem­ber that the flue system must have a fall of about
35 mm per metre of flue DOWNWARD AWAY FROM
the boiler. There must NEVER be a downward in­cline towards the boiler.

Cutting the flue hole

• Making allowance for the slope of the flue, cut
hole in external wall, preferably using a core drill.
For installations with internal and external access ­Use a 105 mm diameter core drill.
For installations with internal access only - Use a
125 mm diameter core drill.
Important: Before cutting the hole for flues to the
rear of boiler, always cover fixing jig to make sure it
is not damaged.

Calculation of flue cutting lengths

• Measure wall thickness e (mm).

• For side flues, measure distance from inside face
of side wall to centre line of flue and subtract 176
mm for right hand flue or subtract 234
for left hand flue to get dimension a (mm), see
diagram 13 or 14.

• Refer to table 1 for cutting lengths of both inner
and outer flue pipes for each of the various flue
options available.
Important: All flue cutting lengths must be meas­ured from the terminal end of the flue pipes, see
diagram 15.
When the dimension X measured on site is greater
than that given in table 1, a flue extension kit will
be required, refer to table 2 for details.

Refer to table 1 for the cutting lengths of both the
inner and outer pipes for each of the flue options
available.

Diagram 12

e

Diagram 13

234

29

mini

a

60

50

Ins 012a

X

Hab 208

Table 1
Flue cutting lengths

Cutting length (mm)

Flue option outer pipe inner pipe Comments

Rear outlet e + a + 96 e + a + 173 maximum
Side flue to distance 'X'
left without
(Diagram 13) extension

Rear outlet e + a + 154 e + a +231 maximum
Side flue to distance 'x'
right without
(Diagram 14) extension

1080 mm

1080 mm

Diagram 14

Hab 209

11

REAR OUTLET FLUE INSTALLATION

Extended flue

The horizontal flue is extended by using one or more
of the 1000 mm extension pipes, Saunier Duval part
number 85091. These are connected together by
push fit type joints, clamps and seals.

Calculation of flue cutting lengths for extended flue

• Using the correct number of extension kits as ta­ble 2, measure dimensions a and e, see diagram
13 or 14. Cut both the inner and outer pipe to the
dimensions given in table 3.

Important: All cutting lengths should be measured

from the push fit end of the extension pipe. Do not
leave any burrs or sharp edges on the cut ends of
the pipes.

Outer pipe

Cutting length

Inner pipe

Cutting length

Installation of flue assembly-direct rear flue

• Fit rubber sealing collar (C) into groove at the
outer end of pipe (A), see diagram 16.

• Fit outer pipe (A) into wall with groove to the
outside.

• Pull pipe inwards to bring rubber sealing collar
hard up against external wall, see diagram16.

• Fit internal plastic flange (F) onto outer pipe. Push
along the pipe until engaged against internal wall.

• From inside, insert inner pipe (B) into outer pipe
turning anti-clockwise to allow inner to fully enter
outer pipe.

• Fit rubber sleeve (H) onto outer pipe.

• Take hold of inner flue,twist clockwise and push
gently onto fan outlet.

• Pull rubber sleeve onto boiler spigot ensuring a
good seal.

Installation of flue assembly-side flue

• Fit rubber sealing collar (C) into groove at the
outer end of pipe (A), see diagram 16.

• Fit outer pipe (A) into wall with groove to the
outside.

• Pull pipe inwards to bring rubber sealing collar
hard up against external wall, see diagram16.

• Fit internal plastic flange (F) onto outer pipe. Push
along the pipe until engaged against internal wall.

• From inside, push inner pipe (B) into outer pipe
turning anti-clockwise to allow inner to fully enter
outer pipe.

• Fit rubber sleeve (H) onto outer pipe.

• Fit both 'O' rings (F) into flue elbow (D), one at
the inlet, one at the outlet. By necessity, they are a
loose fit, apply a small amount of silicone grease
to each 'O' ring when fitting.

Diagram 15

Table 2
Number of extension kits required

Flue option Dimension 'X' No. of

extension kits

Side flue 1081 to 1811mm 1

(left or right) 1812 to 2542 mm 2

Table 3
Extended flue cutting lengths

Cutting length (mm)

Flue option outer pipe inner pipe Comments

Rear outlet e + a - 906 e + a + 829 maximum
Side flue to distance 'X'
left without
(Diagram 13) extension

1080 mm

Rear outlet e + a - 848 e + a + 771 maximum
Side flue to distance 'x'
right without
(Diagram 14) extension

1080 mm

Ven 089

Important: If the flue has been cut, ensure that there
are no burrs that could damage the 'O' ring.

• Remove the backing from the self adhesive gas­ket (J) and carefully fit gasket to base of flue el­bow.

• Fit elbow onto boiler and secure with the four
screws (G).

• Take hold of inner flue, twist clockwise and push
gently onto the elbow outlet taking care not to tear
the 'O' ring.

• Pull rubber sleeve onto elbow ensuring a good
seal.

12

Diagram 16

Pho 087

TOP OUTLET FLUE INSTALLATION

Top outlet flue - kit 86151 see diagram 18, is 1000 mm long
and comprises:

- Outer pipe ....................................................................... A

- Inner pipe ........................................................................ B

- External rubber sealing collar ........................................ C

- Flue elbow .......................................................................D

- Internal flange ................................................................ E

- 'O' rings ............................................................................. F

- Screws ............................................................................ G

- Rubber collar .................................................................. H

- Clamp and seal ............................................................... I

- Gasket .............................................................................. J

A - Flue to rear of boiler

• Mark correct position of hole from template.

B - Flue to side of boiler

• Mark horizontal centre line for hole on rear wall. Extend
horizontal centre line to side wall and mark vertical centre
line of flue hole as shown in diag. 12.

Under normal circumstances, it will be possible to gain ac­cess to the outside of the building to fit the flue terminal
assembly. Where outside access is not possible e.g. high
rise buildings, the flue terminal can be fitted from inside the
building only if required.

Note : When cutting flue hole and when extending flue
centre line to a side wall, remember that the flue system
must have a fall of about 35 mm per metre of flue DOWN­WARD AWAY FROM the boiler. There must NEVER be a down­ward incline towards the boiler.

Cutting the flue hole

• Making allowance for the slope of the flue, cut hole in
external wall, preferably using a core drill.
For installations with internal and external access - Use a
105 mm diameter core drill.
For installations with internal access only - Use a 125 mm
diameter core drill.
Important: Before cutting hole for flues to rear of boiler, al­ways cover fixing jig to make sure it is not damaged.

Table 1 :

Flue Cutting length (mm)

Flue option outer pipe inner pipe Comments

Top outlet e + a + 125 e + a + 202 maximum
Side flue to distance 'X' without
(left or right) extension 1080 mm

Calculation of flue cutting lengths

• Measure wall thickness e (mm), see diagram 17.

• For side flues, measure distance from inside face of side
wall to centre line of flue and subtract 205 mm for both
right and left hand flues to get dimension a (mm).

• Refer to table 1 for cutting lengths of both inner and outer
flue pipes for each of the various flue options available.
Important: All flue cutting lengths must be measured from
the terminal end of the flue pipes, see diag. 15.

When the dimension X measured on site is greater than that
given in table 1, a flue extension kit will be required, refer to

table 2 for details.
Extended flue

The horizontal flue is extended by using one or more of the
1000 mm extension pipes, Saunier Duval part number 85091.
These are connected together by push fit type joints, clamps
and seals.

Calculation of flue cutting lengths for extended flue

• Using the correct number of extension kits as table 3,
measure dimensions a and e, see diagram 17.
Important: All cutting lengths should be measured from the
push fit end of the extension pipe. Do not leave any burrs or
sharp edges on the cut ends of the pipes.

ee

a

X

Diagram 17

a

X

A

B

G

I

C

H

E

extension kits

D F

J

Diagram 18

Table 2 : Number of extension kits required

Flue option Dimension 'X' No. of

Side flue 1081 to 1811 mm 1

(left or right) 1812 to 2542 mm 2

Table 3 :

Extended Flue Cutting length (mm)

Flue option outer pipe inner pipe Comments

Top outlet e + a + 877 e + a + 800 maximum
Side flue to distance 'X' without
(left or right) extension 1080 mm

Installation of flue assembly

• Fit rubber sealing collar (C) into groove at the outer end
of pipe (A), see diagram 18.

• Fit outer pipe (A) into wall with the groove to the outside.

• Pull pipe inwards to bring rubber sealing collar hard up
against external wall, see diagram16.

• Fit internal plastic flange (E) onto outer pipe. Push along
the pipe until engaged against internal wall.

• From inside, insert inner pipe (B) into outer pipe.

• Fit both 'O' rings (F) into the flue elbow (D), one at the
inlet, one at the outlet. By necessity, they are a loose fit,
apply a small amount of silicone grease to each 'O' ring
when fitting.
Important: If the flue has been cut, ensure that there are no
burrs that could damage the 'O' ring.

• Remove the backing from the self adhesive gasket (J)
and carefully fit gasket to base of flue elbow.

• Fit elbow onto boiler and secure with the four screws
(G).

• Take hold of inner flue, twist clockwise and push gently
onto the elbow outlet taking care not to tear the 'O' ring.

• Fit clamp and seal (I) onto outer pipe ensuring a good
seal.

Hab 210b

Pho 422

13

ELECTRICAL CONNECTION

Warning. This boiler must be earthed
All system components must be of an approved
type.
The mains electrical cable is supplied with the boiler.
It is coiled ans tucked inside the boiler

Connection of the whole electrical system and any
heating system controls to the electrical supply must
be through a common isolator.
Isolation should preferably be by a double pole
switched fused spur box having a minimum con­tact separation of 3 mm on each pole. The fused
spur box should be readily accessible and prefer­ably adjacent to the boiler. It should be identified
as to its use.
A fused three pin plug and shuttered socket outlet
may be used instead of a fused spur box provided
that:
a) They are not used in a room containing a fixed
bath or shower.
b) Both the plug and socket comply with the cur­rent issue of BS1363.
The mains electrical supply must be maintained at
all times in order to provide domestic hot water.
Do not interrupt the mains supply with a time switch
or programmer.

WARNING: ON NO ACCOUNT MUST ANY EXTERNAL
VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON
THE HEATING CONTROLS CONNECTION PLUG.

Warning: This appliance must be wired in accord-

ance with these instructions. Any fault arising from
incorrect wiring cannot be put right under the terms
of the Saunier Duval guarantee.

Time clock

A mechanical or digital time clock is available as
an accessory, Saunier Duval part N° 86148 (me­chanical) or 86149 (digital).

External controls

The THEMA boiler is designed to operate at maxi­mum efficiency at all times. The of a programma­ble electronic room thermostat is recommended
for optimum performance, Saunier Duval part
number 40010. Please contact your supplier.

The boiler will work for heating without a room ther­mostat and/or timeswitch being connected pro­vided that the wire link fitted between the two ter­minals of the connector (E) is left in place, see dia-

gram 19.

A 230V room thermostat can be used but do not
make any connection to the compensating resis­tor, see diagram 19.
ON NO ACCOUNT must any electrical voltage be
applied to any of the terminals of the external con­trols plug.

E

The mains electrical cable is supplied with the

boiler. It is coiled and tucked inside the boiler

THEMA F 23 E

For no external controls

leave wire link (E) in place

sch 228

Cylinder

When fitting room thermostat,

remove wire link (E) and connect

voltage free thermostat as shown

°C

sch 229

THEMA F SB 18 E
THEMA F SB 23 E

°C

Diagram 19

14

°C

sch 227

COMMISSIONING

The commissioning and first firing of the boiler must
only be done by a competent person.

Gas installation

It is recommended that any air is purged from the
supply at the gas inlet test point on the left hand
side of the gas valve, see diagram 20.

Filling the system

1

Open shut off
valves (slot of
screw corre­sponds to flow
direction).

3

Open the tap on the sys­tem filling loop and fill the
system until the pressure
indicated on the display
is between 1 and 2 bar.

➜

➜

➜

Ins 017a

Sec 055

Diagram 20

2

Undo, but do not
remove, cap on
automatic air
vent on top of
pump. Do not re­tighten cap.

mec 117

Reg 008

Bleed air from the

4

heat exchanger by un­doing the air bleed cap.
Do not re­move this
cap. When
all the air
has been
removed,
tighten
cap.

Reg 007

Important:

- If this procedure is not carried out properly, the boiler
will go into safety lock-out until all of the air has been
purged.

- When venting air from boiler, do not touch the
schrader valve on the expansion vessel, it is NOT a
vent.

- Before starting the boiler, turn the pump impellor to
make sure it is free to move.

• Unscrew black cap on front of pump.

• Using screwdriver, push in pump spindle and turn
pump impellor 3 to 4 times. DO NOT HIT SPINDLE. Re­place black cap.

Starting the boiler

Before starting the boiler check that:

- The gas meter tap is open. If using Butane or Pro­pane, check that valve on storage cylinder or tank is
open.

- you have removed the two fan transist clips from fan.

Bleed each radia

5

tor until a continu­ous jet of water is ob­tained.

Open various

6

hot water taps to

bleed system.

Ins 061

- The boiler gas service cock is open.

- The boiler is connected to the electrical supply and
switched on.

- The front casing is fitted.

First starting up

• Following the instructions given in the 'User Instruc­tions' set boiler to run in central heating mode.

• Set boiler thermostat for maximum temperature
and check that any external controls, if fitted, are
calling for heat.

• Allow the temperature to rise to the maximum
value, with all radiator valves open.
The temperature rise will cause release of the gases
contained in the water of central heating system.

- Gases driven towards the boiler will be automati­cally released through the automatic air vents.

- Gases trapped at the highest point of the system
must be released by bleeding the radiators.

Ins 062

Make sure that

7

pressure gauge
reads between 1 and
2 bar. Re-pressurise
system as necessary.

Sec 055

15

COMMISSIONING

On reaching maximum temperature, the boiler
should be turned off and the system drained as
rapidly as possible whilst still hot.

• Refill system to a pressure of 1 bar and vent as
before.

• Restart boiler and operate until a maximum tem­perature is reached. Shut down boiler and vent
heating system. If necessary, top up heating sys­tem and make sure that a pressure of 1 bar
is indicated on the pressure gauge when system is
COLD.

Gas pressures

The main burner pressure should be checked dur­ing commissioning to make sure the correct input
is obtained. Proceed as follows:

• Shut down boiler.

• Undo screw on burner pressure test point below
sealed combustion chamber, see diagram 23.

• Connect a suitable pressure gauge.

• Gain access to the rear of the control panel and
locate the range rating adjuster screw, see dia-

gram 24.

• Start boiler as described in 'User Instructions'.

• Set boiler thermostat to maximum and check
that any external controls are calling for heat.

• Check that the reading on the gauge matches
that given in 'Technical Data' for the type of gas
being used.

• Adjust the range rating adjuster screw as neces­sary to obtain the desired input.

• Shut down boiler.

• Remove pressure gauge, tighten up test point
screws and check for gas soundness.

• Using a ball point pen, clearly indicate on the
data label the input the boiler is set to.

Note: This adjustment does not affect the domes­tic hot water output.
If measured burner pressure differs greatly from the
given figure, check the gas inlet pressure as follows:

• Shut down boiler.

Diagram 23

Diagram 24

• Remove screw from inlet test point on the side of
the gas valve, see diagram 23.

• Connect a suitable pressure gauge.

• Start boiler as described in 'User Instructions'.

• Check that the inlet pressure reading matches
that given in 'Technical Data' for the type of gas
being used.

• Shut down boiler.

• Remove pressure gauge, tighten up test point
screws and check for gas soundness.

• If the gas pressure is incorrect, refer to the Fault
Finding section in 'Servicing Instructions'.

• If the inlet pressure is below that given, the gas
supply pipework/meter must be checked and any
fault corrected.

• In the case of an LPG installation, check the stor­age tank or cylinder, regulator and pipework.

Des 044

Reg 056

SAFETY DEVICES

Air flow rate safety device

If an obstruction, even partial, of the flue occurs,
for any reason whatsoever, the built in safety sys­tem of the boiler will turn the boiler OFF and the
fan will continue to run.
The boiler will be ready to operate when the fault
has been cleared.

In case of power supply failure

The boiler no longer operates.
As soon as power supply is restored, the boiler will
be automatically restarted.

Overheat safety

In the event of a problem, the overheat thermos­tat causes safety shutdown of the boiler. Should this
occur, reset the thermostat by pressing in the red
button. The overheat thermostat is located on the
RHS of the heat exchanger.

16

Important notice: A central heating system cannot
operate satisfactorily unless it is properly filled with
water and unless the air initially contained in the
piping systems has been properly bled off. If these
conditions are not satisfied, air noise will occur
within the system.

The THEMA F 23 E boiler has a built in frost protec-
tion device that protects the boiler from freezing. If
the boiler is to be left and there is a risk of frost,
ensure that the gas and electrical supplies are left
connected and the summer/winter switch is in
the position. The frost protection device will light
the boiler when the temperature of the boiler wa­ter falls below 6°C. When the temperature reaches
16°C, the boiler stops.
Note: This device works irrespective of any room
thermostat setting and only protects the boiler.

SETTINGS

Gas valve setting

All boilers are tested and factory set during manu­facture. Should it be necessary to reset a gas valve,
for example after replacement, proceed as follows:

• Shut down boiler.

• Connect a suitable pressure gauge as described
in 'Commissioning'.

Maximum setting

• Remove one electrical connector from the
modulating gas valve coil.

• Turn the domestic hot water
temperature adjuster to maxi­mum setting.

• Remove the protective cover
from the gas valve adjuster.
Using a 2 mm Ø rod, press in the
spindle in the middle of screw M,

see diagram 25.

• Turn nut 'B' to obtain the de­sired pressure, see technical
data.

Minimum setting

This must be done AFTER the maximum setting.

• Hold not B to prevent from turning, turn nut 'A' to
obtain the desired pressure, see technical data.

B

A

Mec 121

Diagram. 26

a

Reg 013

After adjustment, refit the cover to the gas valve
adjuster and refit electrical connector.

Bypass

The THEMA F 23 E has a built-in bypass. This must be
adjusted according to the requirements of the sys­tem, refer to the flow rate pressure curve (diagram

3). The boiler is supplied with the built-in bypass
open a half a turn. It is adjusted by turning the by­pass screw (a), see diagram 26. Turn the screw
clockwise to close the bypass.
When using thermostatic radiator valves (TRV's), it
is recommended that an additional, adjustable
bypass of 15 mm minimum diameter is fitted be­tween the flow and return of the heating circuit,
see diagram 6. Any bypass must be fitted before
system controls.

PCB Settings

The PCB on the Thema F 23 E can be set to operate
in different ways to suit individual installations. The
dip switch SW1, see diagram 27, should be set as
follows:

1 - OFF 4 - OFF
2- ON 5- OFF
3 - OFF 6 - OFF

Diagram. 27

SW1

ON

123456

DIP

Reg 055

CHANGING GAS TYPE

Should it become necessary to change the gas type, a modification kit will be required.
This modification must only be carried out by a suitably qualified engineer.

Conversion: Natural Gas (G20) to G30/G31 Part No. 86161

17

ROUTINE CLEANING AND INSPECTION

To ensure the continued efficient and safe opera­tion of the boiler it is recommended that it is
checked and serviced at regular intervals. The fre­quency of servicing will depend upon the particu­lar installation conditions and usage, but in gen­eral once a year should be enough.

It is the law that any servicing is carried out by a
competent person.

Service Check and Preparation.

• Operate boiler and check for any faults that
need to be put right.

• Isolate boiler from the gas and electrical supplies.

• On completion check all gas carrying parts for
soundness with leak detection fluid.

• The maximum domestic hot water flow rate is 12
litres/minute.

• Remove boiler casing as follows:

Upper front panel

• Hinge down control cover to gain access to con­trol panel.

• Disengage the two 'quarter turn' fasteners by
turning the heads of the screws a quarter of a turn
towards the centre of the boiler.

• Carefully lower the panel down on its hinge until
it is horizontal.

• Turn both plastic catches to release upper front
panel.

• Remove upper front panel by pulling forward at
the bottom and lifting off.
Note: The upper front panel is retained by a plastic
safety strap, disengage this before removal.

Side panels

• From below boiler, unscrew and remove black
plastic screws securing side panels to the boiler.

• Prise out black plastic inserts and lift panel off
boiler.

Diagram 28

from boiler taking care to retain both fibre washers
and seal on gas supply for use on reassembly.

• Unscrew and remove two injector bar retaining
screws and separate injector bar from burner.

• Examine and clean injectors as necessary.
Note: Do not use a wire or sharp instrument on the
holes.

• Replace burner in reverse order to removal.

Heat exchanger

• After removal of burner, examine heat ex­changer for any blockages or build up of deposits.

• Clean using soft brush or vacuum cleaner.
Important: Take care not to scratch or otherwise
damage painted surface of heat exchanger.

Reassembly of parts removed for servicing

• Replace all parts in reverse order to removal.

Des 047

Combustion chamber

• Loosen two wing nuts on combustion chamber
cover.

• Disengage retaining lugs from holes in either side
of combustion chamber and move rods away to
clear combustion chamber sides, see diagram 28.

• Unclip two toggle clips holding upper part of
combustion chamber in place.

• Holding both sides, pull chamber forward to re­lease it from underside of heat exchanger and out
of boiler.

• Take care not to damage insulation material on
inside faces of combustion chamber.

Cleaning the burner

• Pull off leads to ignition electrode.

• Pull off lead to flame sense electrode.

• Unscrew and remove screw holding earth lead
to flame sense electrode.

• Undo main gas supply nut from main burner.

• Unscrew and remove locking nut from both main
gas connection and burner pressure tapping point.

• Lift front edge of burner until tapping point and
gas supply connection are free. Remove burner

Flue system

• Check externally to make sure flue is not blocked.

• Inspect flue system to make sure all fittings are
secure.

Operation of fan

• Switch on electrical supply and turn on gas.

• Switch boiler On/Off switch to 1 (On).

• Light burner by opening a hot tap.

• Without upper front panel in place, burner should
be prevented from lighting by air flow detection
system.

• Refit upper front panel.

• Check that fan runs when burner is lit and stops
when it goes out.

Cold water inlet filter (exept SB models)

• Drain down hot water circuit of boiler as follows:

• Close isolating valve on cold water inlet connec­tion on fixing jig, see diagram 5.

• Open one or more hot water taps to drain boiler.

• Undo connecting nut from cold water inlet con­nection to gain access to filter.

• Remove white filter from inlet connection.

18

ROUTINE CLEANING AND INSPECTION

Note: Connecting pipework is telescopic, it may be
necessary to slide sleeve back for easier access to
filter.

• Clean and inspect filter, replace if necessary.

• With both flow restrictor and filter in place, re­connect pipe to inlet connection and tighten.

• Fully open isolating cock on cold water inlet con­nection and check for leaks.

REPLACEMENT OF PARTS

To replace microswitch assembly exept SB models)

• Disconnect microswitch by pulling off plug.

• Unclip external controls connector from mount­ing bracket.

• Undo two screws securing microswitch assembly
to reversing valve assembly, see diagram 29.

• Remove microswitch assembly from reversing
valve.

• Fit replacement microswitch assembly in reverse
order to removal.

• Reconnect plug and refit external controls con­nection to bracket.

To replace fan

• Disconnect power supply and earth leads to fan.

• Unscrew and remove two fan retaining screws
located at front edge of fan mounting plate.

• Remove fan with mounting plate attached by
pulling forwards and out of boiler.

• Unscrew and remove three screws securing fan
to fan mounting plate.

• Fit replacement fan to mounting plate and se­cure with screws.

• Fit replacement fan to boiler in reverse order to
removal making sure that mounting plate retain­ing lugs are properly engaged into flue hood.

• Reconnect power supply and earth leads.
Important: Make sure that fan outlet is correctly fit­ted into either the flue elbow for top outlet flue, or
the rear connector for rear outlet flue.
Before commissioning boiler, remove the two plas­tic transit clips from replacement fan.

To replace air pressure switch

• Locate air pressure switch in upper left hand cor­ner of sealed chamber.

• Pull off plastic tube from left hand connection.

• Grasp pressure switch and disengage it from
bracket clips by pulling from the top.

• Remove electrical connections from switch.

• Fit electrical connections to terminals 1 and 3 of
replacement switch.

• Fit replacement switch in reverse order to re­moval.
Important: Refit plastic tube to LEFT hand connec­tor (marked P1).

To replace spark generator

• Locate spark generator on bracket to right hand
side of gas valve.

• Undo and remove screw securing lower termi­nal cover to bracket and remove bracket.

• Disconnect four leads from spark generator.

Operation of water valve (exept SB models)

• With the Summer/Winter control in the 'Summer'
position, slowly open a convenient tap until boiler
lights.

• Measure water flow, it should not be greater than
3,5 litres/minute.

• If necessary, replace diaphragm.

• Replace all outer panels.

microswitch on THEMA F 23 E

Diagram 29

Diagram 30

• Undo and remove screw securing spark genera­tor to bracket and remove spark generator.

• Fit replacement spark generator in reverse order
to removal.

• Reconnect two grey power supply leads and two
clear ignition leads to spark generator, the polarity
is not important.

• Refit lower terminal cover.

To replace main printed circuit board (PCB)

• With lower front panel down as described previ­ously, undo and remove screw holding pump con­nection cover to PCB cover, see diagram 30.

• Open cover and unclip plastic clip securing
pump cable to lower front panel.

• Pull off pump connector and earth lead.

• Undo and remove four screws securing PCB
cover to lower front panel.

• Lift off PCB cover.

• Pull off connectors CN6, CN7, CN8 and CN9 on
PCB.

• Undo and remove screw holding PCB to lower
front panel.

• Lifting PCB up slightly on LHS, pull PCB out of elec­trical connector on ignition PCB. Leave ignition PCB
in place.

Sch 228

Hab 286

19

REPLACEMENT OF PARTS

• Fit replacement PCB in reverse order to removal.
Important: When fitting replacement PCB, ensure
that control knob spindles correctly locate into PCB
adjuster slots.

• Refit connectors and covers in reverse order to
removal.

To replace ignition PCB

• Gain access to PCB's as described in previous
section.

• Remove main PCB securing screw as described
in previous section.

• Pull off three electrical connectors on PCB.

• Lift up ignition PCB, separate from main PCB and
remove from boiler.

• Fit replacement PCB in reverse order to removal.

• Refit connectors and covers in reverse order to
removal.

To replace pump

• Drain down heating circuit of boiler only as fol­lows:

• Close isolating valves on flow and return connec­tions on fixing jig, see diagram 5.
Note: These valves are closed when slots are at right
angles to direction of flow.
It is not necessary to drain entire heating circuit to
carry out this work.

• Drain boiler by attaching a plastic tube to drain
outlet and opening drain valve knob anticlockwise,

see diagram 5.

• Gain access to pump connection as described
in 'To replace main PCB'.

• Pull off pump connector and earth lead.

• Pull out retaining clip from telescopic pump out­let connection and slide connection upwards to
release from pump.

• Undo and remove two fixing screws and remove
pump retaining bracket from front of pump.

• Grasp pump body, lift upward to disengage from
reversing valve and turn pump to right. Remove
pump by pulling forward and over reversing valve
assembly.

• Discard old pump inlet 'O' ring.

• Apply silicone grease to new 'O' ring supplied,
and fit onto inlet connection on replacement
pump.

• Fit replacement pump in reverse order to re­moval.
Note: Apply silicone grease to pump outlet con­nection 'O' ring before assembly.

• Refit pump electrical connection.

• Open isolating valves on flow and return connec­tions, refill, vent and pressurise boiler. Check for leaks.

To replace temperature/pressure gauge

• Drain down heating circuit of boiler only as de­scribed in 'To replace pump'.

• Undo and remove screw securing pressure
gauge capillary to front section, see diagram 31.

• Carefully pull capillary from front section.

• Undo and remove two screws securing tempera­ture/pressure gauge to lower front panel and re­move gauge.

• Fit replacement gauge in reverse order to
removal.

Diagram 31

Diagram 32

• Fit capillary of new gauge to front section using
new 'O' ring supplied.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

To replace reversing valve assembly

• Remove temperature/pressure gauge capillary
as described previously.

• Remove pump as described previously.

• Remove microswitch assembly as described pre­viously.

• Remove retaining clip from LHS pipe connection
on front section of valve and disengage pipe.

• Unscrew and disconnect heating flow (centre)
connection at fixing jig.

• Remove retaining clip from heating flow pipe
connection on right of front section.

• Remove flow pipe from boiler.

• Unscrew and disconnect heating return (left
hand) connection at fixing jig.

• Remove retaining clip from expansion vessel pipe
connection at rear of reversing valve assembly and
disengage pipe, pushing pipe back and out of re­versing valve.

• Undo and remove large screw holding water
valve to back plate of reversing valve assembly,

see diagram 32.

Cla 007

Des 054

20

REPLACEMENT OF PARTS

• Push water valve back to disengage it from re­versing valve.

• Unclip and remove loss of water pressure switch
from left of reversing valve assembly, see diagram

33.

• From below boiler, undo and remove three
screws holding reversing valve to bottom plate of
boiler. Remove complete reversing valve assem­bly from boiler.

• Undo and remove heating return connecting
pipe and hose from rear of reversing valve assem­bly. Fit hose to replacement reversing valve assem­bly.

• Fit replacement reversing valve into boiler in re­verse order to removal.
Note: Use new 'O' rings, retaining clip, filter and
washer provided.

• Unscrew and remove microswitch assembly from
top of replacement reversing valve assembly to
allow refitting of water valve.
Note: fit expansion vessel pipe and loss of water
switch to reversing valve assembly before pump,
to ensure that it is correctly located. Apply silicone
grease to all 'O' rings and hoses prior to assembly.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

Diagram 33

Sec 059

To replace reversing valve front section

• Remove pressure gauge capillary as described
previously.

• Remove pipe connections from either side of
reversing valve front section, refer to previous sec­tion.

• Move short selector lever on front of valve to left
hand position.

• From below boiler, undo and remove single screw
holding reversing valve front plate to bottom plate
of boiler.

• Undo and remove six screws holding front sec­tion to rear section of reversing valve, see diagram

34.

• Remove front plate complete with pump bracket
and then front section from reversing valve, along
with rubber sealing gasket.

• Assemble bypass valve provided and fit into hole
in underside of replacement front section. Fit 'U'
shaped retaining clip.
Note: Use bypass valve fitted to original front sec­tion for guidance.

• Fit replacement front section, with gasket, to rear
section.

• Locate front plate and replace six fixing screws.
Take care to evenly tighten screws ensuring they
are not cross threaded.

• Refit pipe connections to either side of front sec­tion using new 'O' rings provided. Apply silicone
grease to 'O' rings before fitting.

• Refit pressure gauge capillary in reverse order to
removal.

• Ensure short selector lever on front of valve is set
to right hand position.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

Diagram 34

Cla 007

To replace loss of water switch

• Drain down heating circuit of boiler only as de­scribed in 'To replace pump'.
Note: It is not necessary to drain entire heating cir­cuit to carry out this work.

• Pinch plastic cover to release retaing clips and
remove cover from switch. Pull plug lead from
switch terminals.

• Remove clip holding switch into left side of re­versing valve assembly.

• Pull switch out of reversing valve assembly, see

diagram 33.

• Fit replacement switch in reverse order to re­moval, using new 'O' ring provided and applying
silicone grease to 'O' ring before fitting.

• Reconnect plug to switch terminals.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

To replace water valve or diaphragm (except SB
models)

• Drain down hot water circuit of boiler only as
described in 'Routine Cleaning and Inspection'.

• Remove microswitch assembly as described pre­viously.

• Unscrew connecting nut from cold water inlet
connection, second from left on fixing jig. Keep fil­ter and flow regulator.

• Remove clip holding connecting pipe in rear of
water valve. From below boiler, grip clip with long
nosed pliers and pull down.
Note: This connecting pipe is telescopic, it may be
necessary to slide back brass sleeve to facilitate
removal.

21

REPLACEMENT OF PARTS

• Remove clip holding pipe to heat exchanger in
rear of water valve. From front of boiler, grip clip
with long nosed pliers and pull upwards.

• Unscrew and remove large screw holding water
valve to back plate of reversing valve assembly,

see diagram 32.

• Disengage water valve from reversing valve and
remove from boiler.
Note: When disengaging water valve from heat
exchanger pipe, check that non-return valve is not
held on end of pipe. If so, carefully separate pipe
from valve to ensure that small spring and plunger
do not fly out and are lost.

• To replace diaphragm, undo five screws and
separate main components of water valve.

• If white diaphragm cover is to be replaced, sepa­rate original from water valve end casting and fit
replacement cover.

• Fit replacement diaphragm , making sure that
metal disc FACES diaphragm cover and beaded
edge of diaphragm is correctly fitted in correspond­ing groove in both cover and plastic housing, see

diagram 35.

• Reassemble water valve, evenly tightening five
screws.

• Fit water valve actuating pin into hole in dia­phragm cover, through nose end of valve and and
push in until flush, or slightly below, nose end of
valve.
Note: Apply silicone grease to pin before fitting.

• Refit water valve to boiler, locating nose end into
rear of reversing valve assembly, 'springing' heat
exchanger pipe to gain clearance as necessary.
Fit large water valve retaining screw but do not
tighten fully at this stage.

• Apply silicone grease to 'O' ring and fit onto end
of heat exchanger pipe. Fit pipe into water valve
by pulling it forward. Make sure that 'O' ring is cor­rectly located.

• Whilst holding pipe in rear of water valve, fit re­taining clip. This should easily clip over pipe and
should NOT have to be forced. If resistance is ex­perienced, either pipe is not correctly fitted in rear
of water valve or clip is not being fitted properly
through slot between back plate and plastic hous­ing of water valve. When clip is fitted, check con­nection by pushing pipe back away from water
valve.

• Refit telescopic connecting pipe to inlet of wa­ter valve after applying silicone grease to 'O' ring.
Fit retaining clip into groove on connecting pipe,
through slot between back plate and water valve
plastic housing. Check connection by pulling pipe.
Make sure that clip is not loose and likely to fall out
at a later date. If in doubt, fit a new clip.

• With both flow regulator and and plastic filter
washer in place, refit connecting nut to inlet con­nection and tighten.

• Open isolating valve on cold water inlet connec­tion and check for leaks.

• Replace microswitch assembly.

To replace gas valve

• Ensure gas supply is off.

• Disconnect two black electrical leads from gas
valve modulating coil.

Diagram 35

Diagram 36

• Disconnect two white and one red lead from gas
valve main solenoid.

• Pull off clear plastic tube from gas valve to sealed
chamber tapping point.

• Unscrew main gas supply pipe nut on top of gas
valve, releasing spark ignition unit bracket, see dia-

gram 36.

• From below boiler, unscrew gas valve connec­tion between gas valve and fixing jig isolating cock.

• Unscrew and remove two screws securing gas
valve to bottom plate of boiler.

• Remove gas valve from boiler.

• Refit replacement gas valve in reverse order to
removal.
Note: Use new 'O' ring provided between gas valve
and burner supply pipe.

• Refit electrical connections to replacement gas
valve as follows:

- BLACK leads to modulating coil.

- WHITE leads to EV1 and EV2 terminals of main

solenoid

- RED lead to COM terminal of main solenoid.

To replace modulating coil

• Ensure gas supply is off.

• Disconnect two black electrical leads from gas
valve modulating coil.

• Unscrew and remove two screws holding modu­lating coil to gas valve and remove coil from gas
valve.

• Fit replacement modulating coil in recerse order
to removal.

• Reconnect electrical leads to replacement coil.
Note: All boilers are tested and factory set during
manufacture. Should it be necessary to reset a gas
valve, for example after replacement, refer to 'Set-

tings'.

Des 058

Mec 117

22

REPLACEMENT OF PARTS

To replace safety valve

• Drain down entire heating system.

• From below boiler, disconnect heating flow pipe
from rear of fixing jig.

• Undo heating flow connection on front of fixing
jig. Remove clip from heating flow pipe connec­tion on right of front section of reversing valve. Pull
pipe towards right and out of reversing valve. Re­move pipe from boiler and keep.

• From below boiler, disconnect safety valve dis­charge pipe.

• Working through boiler from the front using a long
screwdriver, undo and remove screw holding safety
valve assembly to fixing jig.

• Remove complete safety valve assembly from
fixing jig and remove from boiler.

• Fit replacement safety valve in reverse order to
removal.
Note: Apply silicone grease to 'O' ring before fixing
pipe into right hand side of reversing valve.

• Refill heating system and boiler, vent and pres­surise as described previously.

To replace heat exchanger

• Drain down both heating and hot water circuits
of boiler only as described previously.
Note: It is not necessary to drain entire heating sys­tem to carry out this work.

• Remove combustion chamber cover as de­scribed in 'Routine Cleaning and Inspection'.

• Remove two clips from heating connections to
left side of heat exchanger.

• Remove clip holding pump outlet connection
into pump and slide connection up pump outlet
pipe. Pull complete pipe down to disengage from
heat exchanger.

• Remove retaining clip from LHS pipe connection
on front section of valve and disengage pipe.

• Disengage pipe downwards from heat ex­changer.

• Unscrew and disconnect two hot water connec­tions to right side of heat exchanger.

• Grasp both sides of heat exchanger and slide
forwards and out of boiler.

• Fit replacement heat exchanger in reverse or­der to removal.
Note: Use new sealing washers and 'O' rings pro­vided.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

To replace expansion vessel
1 Boiler in place
Note: The expansion vessel can be replaced with

the boiler in place provided that there is a mini­mum clearance of 400mm on one side of the boiler
and that no vertical pipework passes between
boiler and wall on that side.

• Drain down the heating circuit of the boiler only
as described in 'To replace pump'.
Note: It is not necessary to drain entire heating sys­tem to carry out this work.

• Remove pump from boiler as described previ­ously.

• Unscrew pipe connection nut from expansion
vessel and disengage pipe from connection. Keep
sealing washer.

• Whilst supporting weight of vessel, push bottom
of vessel away from boiler, disengaging threaded
connection from hole in rear of boiler. Allow vessel
to drop out of its two upper retaining brackets.

• Remove vessel to side of boiler.

• Fit replacement expansion vessel in reverse or­der to removal ensuring that sealing washer is fit­ted to vessel pipe connection.

• Check that vessel charge pressure is 1bar. Cor­rect if necessary.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

2 Boiler removed from wall

• Drain down the heating circuit of the boiler only
as described in 'To replace pump'.
Note: It is not necessary to drain entire heating sys­tem to carry out this work.

• Ensure that gas and electrical supplies to boiler
are turned off.

• Disconnect flue from either rear or top of boiler
as applicable.

• Disconnect external controls connections, if ap­plicable.

• Unscrew and disconnect five connections be­tween fixing jig and boiler.

• Disengage pipe connections. Lift boiler off hang­ing bracket and place on a convenient working
surface.

• Remove expansion vessel from boiler as de­scribed in previous section.

• Fit replacement vessel in reverse order to removal
and check charge pressure.

• Replace boiler on wall, tighten all connections,
gas connection first, ensuring that all sealing wash­ers, filters and the cold water flow regulator are fit­ted before tightening.

• Reconnect flue system.

• Open isolating valves on flow and return con­nections, refill, vent and pressurise boiler. Check for
leaks.

• Reconnect external controls connections, if ap­plicable.

• Reconnect gas and electrical supplies to boiler.

• Check for gas soundness.

To replace boiler thermistor

• Locate boiler thermistor on heating flow pipe on
left hand side of boiler, see diagram 37.

Diagram 37

23

REPLACEMENT OF PARTS

• Unclip thermistor from pipe.

• Pull off electrical cennections from thermistor.

• Fit replacement thermistor in reverse order to re­moval.
Note: No heat sink compound is required. The po­larity of the connections is not important.

To replace overheat thermostat

• Locate the overheat thermostat on the right
hand side of the heat exchanger.

• Pull off the electrical connections from the ther­mostat.

• Unscrew and remove two screws holding ther­mostat to heat exchanger.

• Fit replacement thermostat in reverse order to
removal, using heat sink compound on the con­tact surface of thermostat.

• Refit electrical leads, the polarity is not impor­tant.

To replace combustion chamber insulation
Front section

• Remove combustion chamber from boiler as
described in 'Routine Cleaning and Inspection'.

• Slide side panels out of combustion chamber
sides.

• Lift front insulation panel free from retaining lugs
and away from cover.

• Fit replacement panels in reverse order to re­moval.

Rear panel

• Remove burner from boiler as described in 'Rou­tine Cleaning and Inspection'.

• Remove clip from base of insulation panel.

• Pull bottom edge of insulation panel forward,
downward and out from behind heat exchanger.

• Fit replacement panel in reverse order to re­moval.

• Replace burner into boiler in reverse order to re­moval.

To replace ignition electrode

• Remove combustion chamber from boiler as
described in 'Routine Cleaning and Inspection'.

• Pull off ignition leads from ignition electrode.

• Unscrew and remove two screws holding igni­tion electrode onto burner.

• Fit replacement ignition electrode in reverse or­der to removal.

• Refit ignition leads, the polarity is not important.

To replace burner

• Pull off ignition and flame sense leads from elec­trodes.

• Remove burner from boiler as described in 'Rou-
tine Cleaning and Inspection'.

• Remove ignition and flame sense electrodes as
described in previous sections.

• Unscrew and remove two screws holding burner
injector bar to burner and remove injector bar.

• Asemble replacement burner, supplied in parts,
as follows:

• Fit burner injectors to injector bar and tighten.

• Assemble burner elements (14) into front and rear
burner supports with securing pins and rods, using
original burner for guidance.

• Fit burner injector bar to burner.

• Fit ignition and flame sense electrodes to burner.

• Fit replacement burner to boiler in reverse order
to removal.

• Reconnect ignition and flame sense leads to
electrodes. Reconnect earth lead to flame sense
electrode. The polarity of the ignition leads is not
important.

To replace burner injectors

• Remove burner as described previously.

• Remove ignition and flame sense electrodes as
described in previous sections.

• Unscrew and remove two screws holding burner
injector bar to burner and remove injector bar.

• Unscrew and remove burner injectors from burner
bar.

• Fit replacement injectors to injector bar and
tighten.
Note: make sure that injector size, marked on each
injector, is the same as that given in 'Technical Data'.

• Reassemble burner and replace into boiler in
reverse order to removal.

To replace timeclock

• Gain access to rear of lower control panel as
described in 'Routine Cleaning and Inspection'.

• Unscrew and remove two screws holding
timeclock to lower control panel.

• Remove PCB cover.

• Remove timeclock plug from connection CN7
on main PCB.

• Fit replacement timeclock in reverse order to re­moval.

To replace flame sense electrode

• Remove combustion chamber from boiler as
described in 'Routine Cleaning and Inspection'.

• Pull off lead from flame sense electrode.

• Unscrew and remove screw holding earth lead
to flame sense electrode.

• Unscrew and remove screw holding flame sense
electrode onto burner.

• Fit replacement flame sense electrode in reverse
order to removal.

• Refit lead.

24

SCHEMATIC WIRING DIAGRAM

THEMA F 23 E PCB

EV1

Ra

P

SW3

P

Diagram 38

6.13

6.14

TA

6.15

6.11

6.12

6.9

K5

6.8

6.6

6.4

6.2

CTN

6.3

2.2

2.1

N

L

9.1 9.2 8.4 8.3 8.2 8.1

IG

TRA

IG - ON/OFF switch
P - Pump
SW3 - Microswitch
K4 - Hight limit thermostat
K5 - Loss of water switch
EV1 - Gas valve modulating coil
TA - Room thermostat (if fitted)
CTN - Boiler thermistor
EV - Gas valve
AL - Ignition unit
FA - Ignition electrode
FL - Flame sense electrode
TRA - Transformer
Pr - Air pressure switch
EX - Fan

14.9

FL

14.8

Pr

14.6

14.5

K4

14.4

12.2

12.1

14.3

14.7

14.2

14.1

13.4

13.1

13.3

13.2

EV

Al

FA

Ex

Sch 242

THEMA F SB 18 E and THEMA F SB 23 E PCB

EV1

6.14

TA

6.15

6.11

Ra

TH

V3V

P

Diagram 39

6.12

6.9

K5

6.8

6.6

6.4

6.2

CTN

6.3

3.3

3.2

3.1

2.2

2.1

N

L

9.1 9.2 8.4 8.3 8.2 8.1

IG

TRA

IG - ON/OFF switch
P - Pump
K4 - Hight limit thermostat
K5 - Loss of water switch
EV1 - Gas valve modulating coil
TA - Room thermostat (if fitted)
CTN - Boiler thermistor
EV - Gas valve
AL - Ignition unit
FA - Ignition electrode
FL - Flame sense electrode
TRA - Transformer
Pr - Air pressure switch
EX - Fan
TH - Cylinder thermostat

14.9

FL

14.8

Pr

14.6

14.5

K4

14.4

12.2

12.1

14.3

14.7

14.2

14.1

13.4

13.1

13.3

13.2

EV

Al

FA

Ex

Sch 240

25

FAULT FINDING

Prior to fault finding, check :
Inlet gas pressure = 20 mbar
Electrical supply = 240 V - 50 Hz
Central heating system is pressurised at 1 - 1,5 bar.
Overheat thermostat on RHS of heat exchanger has
not tripped reset if necessary.

Carry out electrical system checks i.e. earth continu­ity, resistance to earth, short circuit and polarity with
a suitable meter.
Note : these must be repeated after any servicing or
fault finding. Ensure that all external controls are cor­rectly wired and calling for heat.

The fault finding charts will enable the majority of faults
to be diagnosed. To use the charts effectively, it is
necessary to determine exactly which aspects of the
boiler are working correctly and which are not.

NO CENTRAL HEATING

Turn ch temp. control to

max. does burner fire ?

For example:
If the domestic hot water works but the heating
doesn’t, refer to chart No. 1.
If heating works correctly but the hot water doesn’t,
refer to chart No. 2.

IMPORTANT: Always adopt a logical, step by step pro­cedure starting at the beginning of the appropriate
fault finding chart.

WARNING. Always isolate the boiler from the electri­cal supply before carrying out any electrical replace­ment work.
Always check for gas soundness after any service
work.

NO

Does pump run ?

YES

Does fan run ?

YES

Is short selector lever on

front of reversing valve in

right hand position ?

YES

Does burner fire when
a hot tap is opened ?

YES

External controls

(if fitted)

Short out external controls

connection on top of

reversing valve. Does

burner fire ?

NO

Remove leaos from boiler

thermistor. Check its

resistance according to

thermistor value table.

is thermistor ok ?

YES

Replace main pcb

YES

NO

NO

Refer to chart n°3

NO

Refer to chart n°4

NO

Refer to chart n°2

YES

Rectify wiring

operation faults on

external controls

Replace thermistor

Internal control

(clock)

Is there
continuity across
terminals 3 and 4

of clock ?

NO

Is clock calling for

heat ?

YES

Replace clock

YES

Is wiring between

clock and pcb

connection cn7 ok ?

YES

Replace

main pcb

CHART 1

26

FAULT FINDING

Open hot tap fully.

Does burner fire ?

NO

With selector switch/thermostat

in position and turner to maxi-

mum. Does burner fire for CH ?

YES

Is there at least 3 litres/min

water flow at tap ?

YES

Check operation of water valve

diaphragm. Does reversing

valve mechanism move when

hot tap is opened ?

YES

Is there continuity across DHW

microswitch and PCB

connections cn 6.4 and cn 6.9 ?

YES

Remove leads from boiler

thermistor. Check its resistance

in accordance with thermistor

value table. Is thermistor ok ?

NO HOT WATER

(except SB models)

NO

Refer to chart n°2

NO

Check mains water

supply, water filter

NO

Replace

diaphragm

NO

Replace dhw

microswitch

NO

Replace thermistor

Replace main pcb

PUMP NOT RUNNING

Is there 240 v at pump ?

NO

Is there 240 v at

terminal cn2 of PCB ?

NO

Replace main PCB

CHART 3

FAN NOT RUNNING

Is there 240 v at fan ?

NO

Replace main PCB

CHART 4

YES

YES

Free pump

YES

Is pump jammed ?

NO

Replace

pump motor

Is fan jammed ?

NO

Replace fan

CHART 2

Termistor Values

Temperature (°C) 0 5 10 15 20 25 30 35 40 45 50
nominal resistance (Ω) for NTC 32565 25345 19875 15700 12500 10000 8060 6535 5330 4370 3605

Temperature (°C) 55 60 65 70 75 80 85 90 95 100
nominal resistance (Ω) for NTC 2989 2490 2085 1755 1480 1260 1070 920 785 680

SPARE PARTS

When ordering spare parts, quote the part number and description, stating the appliance model number
and serial number from the data badge.

Short parts list

No. Description Part No.

1 Fan 57059
2 Pump 51236
3 Spark generator 51110
4 Air pressure switch 51692
5 Main PCB (SB models) 57267
6 Main PCB (THEMA F 23 E) 57265

No. Description Part No.

7 Control PCB (all models) 57277
8 Water valve diaphragm kit 52519
9 Microswitch assembly (THEMA F 23 E)51590
10 Temperature/pressure gauge 57278
11 Boiler Thermistor 57060
12 Overheat thermostat 51199

27

28

108198 B 06/98