Saunier Duval THEMA F SB 23 E User guide

1
Heating and hot water for the professionals
01773 828100
IN WARRANTY
TECHNICAL HELPLINE
01773 828400
THIS IS A CAT II2H3+ APPLIANCE
THEMAF
Installation and Servicing Instructions

2
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
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
SERVICING SECTION
Mandatory warning notice for CEE countries
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.
UK

3
INTRODUCTION
The THEMA F 23 E boiler is a wall mounted modulat-
ing combination boiler with electronic ignition pro-
viding central heating and instantaneous domes-
tic 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 boilers are wall
mounted modulating boilers with electronic igni-
tion 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 King-
dom, 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.
The boiler is supplied for rear outlet flue connec-
tion. 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 asso-
ciated safety devices are all fitted within the boiler.
The boiler can be installed against either an exter-
nal 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 compe-
tent person in accordance with the relevant re-
quirements of The Building Regulations, The Water
Byelaws, The Building Standards (Scotland) Regu-
lations and any applicable local regulations.
Ancillary equipment
A range of flue accessories are available includ-
ing vertical flues, twin-pipe flues, bends etc.
For further information contact your supplier.
Diagram 1
THEMA SB 18 E and SB 23 E
THEMA F 23 E
Diagram 2
DIMENSIONS
The boiler is delivered in three
separate packages:
- The boiler
- The fixing jig
- The flue system
Net weight: 41 kg
Gross weight : 43 kg
Hab 271a
378
410
857
234
623
802

4
Burner injector mm 1,20 1,20 1,20
Inlet pressure mbar 20 20 20
Diaphragme mm — — —
Gas rate (maximum) m3/h 2,70 2,17 2,70
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
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
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 — — —
Gas rate (maximum) m3/h 3,88 3,88
Gas rate (minimum) m3/h 1,63 1,63 1,63
THEMA F 23 E
TECHNICAL DATA
THEMA F SB 18 E
THEMA F SB 23 E
Heating output automatically variable from (kW) 8,9 8,9 8,9
(BTU/H) 30,000 30,000 30,000
to (kW) 23,3 18,5 23,3
(BTU/H) 80,000 63,000 80,000
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 — —
(BTU/H) 30,000 — —
to (kW) 23,3 — —
(BTU/H) 80,000 — —
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
Natural Gas
(G20)
Butane
(G30)
Propane
(G31)
Town gas
(G130)

5
Available pressure (kPa) between heating
flow and return
(10 kPa = 1 m WG)
1
2
3
4
5
50
40
30
20
10
0500 1000
1
2
3
5
4
Flow rate through heating system (I/h)
Pump :
The performance of the pump varies according to the pump bypass setting, see diagram 3.
Diagram 3
TECHNICAL DATA
Heat output
(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
Heat input
(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
Bypass fully shut
Open 1/4 turn
Open 1/2 turn
Open 1 turn
Open 2 turns
Pom 052
Pressure table :

6
BOILER SCHEMATIC
Shy 131
AB CDE
4
5
14
3
17
19
8
9
10
11
13
12
16
20
21
6
24
22
23
Diagram 4
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
A- Heating return
B- Cold water inlet
C- Heating flow
D- Domestic hot water flow
E- Gas supply
THEMA F 23 E
22
23
ACE
4
16
17
19
6
8
9
10
11
13
12
21
3
14
24
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
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

7
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.
FIXING JIG
12
3
5
67
4
55 55
57,5 57,5
r
p
q
34
25
23
113
s
33
A
B
C
D
E
m
Pla 105c
Filters and washers :
1 - Washer
2 - Metal filter
3 - Flow regulator
4 - Plastic filter
5, 6 & 7 - Washers
Diagram 5
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.
12
5
7
r
p
q
25
23
113
23
s
A
C
E
m
115
110
Pla 116b
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 wa-
ter inlet during installation. This limits the flow through
the boiler to a maximum of 12 l/min.

8
HEATING SYSTEM DESIGN
Diagram 6
• The THEMA F boiler is compatible with any type of
installation.
• Heating surfaces may consist of radiators, convec-
tors or fan assisted convectors.
• Pipe sectional areas shall be determined in accord-
ance with normal practices, using the output/pres-
sure curve (diagram 3). The distribution system shall
be calculated in accordance with the output require-
ments of the actual system, not the maximum output
of the boiler. However, provision shall be made to
ensure sufficient flow so that the temperature differ-
ence 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 heat-
ing 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 serv-
ice pressure of 3 bar. This pressure setting can be modi-
fied 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 manufac-
turers 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.
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 con-
tinuous fall and be routed to a position so that any
discharge of water, possibly boiling or steam, can-
not 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 recom-
mended 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.
Flow
control valve Drain point
Filling point
Bypass
valve
Minimum 22 mm diameter
Tundish
(supplied)
Pressure
reducing
valve
(supplied)
Domestic
water
Heating
circuit
Return
Additional
expansion
vessel
(if required)
Boiler
Hot
Cold supply
Sch 173
• 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 observ-
ing the correct flow and return format as shown in
diagram 6.
PIPING SYSTEM INSTALLATION

9
234
50
mini
29
60
255 mini
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 connec-
tion and soundness testing of all the pipework be-
fore 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, mak-
ing 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 ter-
minal to obstructions and ventilation openings are
shown in diagram 8.
Ins 012a
Diagram 7
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 alu-
minium 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 posi-
tion of the terminal, contact the Saunier Duval
Technical Helpline 01773 828400.
Cupboard or compartment ventilation
The boiler can be fitted in a cupboard or compart-
ment without need for permanent ventilation.
Ven 060b
Diagram. 8
NC
D
M
AB
EF
G
IHL
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
Minimum dimensions (in mm) for the positioning of flue terminals

10
BOILER INSTALLATION
Statutory requirements
The installation of this boiler must be carried out by
a competent person in accordance with the rel-
evant 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.
Ins 020
Ins 021
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 se-
quential order and directions shown on diagram 5.
• Connect the various couplings between the
boiler and the connection plate.
➞
➞
Diagram. 9
Diagram. 10
REAR OUTLET FLUE INSTALLATION
The boiler is supplied for rear outlet flue connec-
tion.
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 assem-
bled.
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.
Pho 422
Diagram 11
A
B
C
J
H
D F
E
G
I

11
234
50
mini
29
60
255 mini
REAR OUTLET FLUE INSTALLATION
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.
Important: When cutting the flue hole and when
extending the flue centre line to a side wall, remem-
ber 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 in-
cline 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 meas-
ured 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.
Hab 209
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
1080 mm
Rear outlet e + a + 154 e + a +231 maximum
Side flue to distance 'x'
right without
(Diagram 14) extension
1080 mm
Diagram 12
Ins 012a
ea
X
Diagram 13
Hab 208
e
a
X
Diagram 14

12
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 ta-
ble 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.
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.
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 gas-
ket (J) and carefully fit gasket to base of flue el-
bow.
• 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.
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
Diagram 15
Ven 089
Cutting length
Outer pipe
Inner pipe
Cutting length
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
Pho 087
Diagram 16

13
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 ac-
cess 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 DOWN-
WARD AWAY FROM the boiler. There must NEVER be a down-
ward 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, al-
ways cover fixing jig to make sure it is not damaged.
Hab 210b
Diagram 17
A
B
C
J
H
D F
E
G
I
Diagram 18
Pho 422
ee a
a
X
X
Table 2 : Number of extension kits required
Flue option Dimension 'X' No. of
extension kits
Side flue 1081 to 1811 mm 1
(left or right) 1812 to 2542 mm 2
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.
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.
Table 1 :

14
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 con-
tact separation of 3 mm on each pole. The fused
spur box should be readily accessible and prefer-
ably 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 cur-
rent 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 (me-
chanical) or 86149 (digital).
External controls
The THEMA boiler is designed to operate at maxi-
mum efficiency at all times. The of a programma-
ble 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 ther-
mostat and/or timeswitch being connected pro-
vided that the wire link fitted between the two ter-
minals 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 resis-
tor, see diagram 19.
ON NO ACCOUNT must any electrical voltage be
applied to any of the terminals of the external con-
trols plug.
sch 229
sch 228
E
°C
For no external controls
leave wire link (E) in place
When fitting room thermostat,
remove wire link (E) and connect
voltage free thermostat as shown
Diagram 19
sch 227
°C
°C
The mains electrical cable is supplied with the
boiler. It is coiled and tucked inside the boiler
THEMA F 23 E
THEMA F SB 18 E
THEMA F SB 23 E
Cylinder

15
COMMISSIONING
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. Re-
place black cap.
Starting the boiler
Before starting the boiler check that:
- The gas meter tap is open. If using Butane or Pro-
pane, check that valve on storage cylinder or tank is
open.
- you have removed the two fan transist clips from fan.
Ins 017a
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.
- 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 Instruc-
tions' 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 automati-
cally released through the automatic air vents.
- Gases trapped at the highest point of the system
must be released by bleeding the radiators.
Diagram 20
Filling the system
1
Open shut off
valves (slot of
screw corre-
sponds to flow
direction).
➜
➜
Sec 055
➜
7
Sec 055
Make sure that
pressure gauge
reads between 1 and
2 bar. Re-pressurise
system as necessary.
46Open various
hot water taps to
bleed system.
Ins 062
Ins 061
5Bleed each radia
tor until a continu-
ous jet of water is ob-
tained.
Reg 007
Bleed air from the
heat exchanger by un-
doing the air bleed cap.
Do not re-
move this
cap. When
all the air
has been
removed,
tighten
cap.
2
3
Open the tap on the sys-
tem filling loop and fill the
system until the pressure
indicated on the display
is between 1 and 2 bar.
Undo, but do not
remove, cap on
automatic air
vent on top of
pump. Do not re-
tighten cap.
Reg 008
mec 117

16
Des 044
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 tem-
perature is reached. Shut down boiler and vent
heating system. If necessary, top up heating sys-
tem 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 dur-
ing 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 neces-
sary 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 domes-
tic 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
SAFETYDEVICES
Air flow rate safety device
If an obstruction, even partial, of the flue occurs,
for any reason whatsoever, the built in safety sys-
tem 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 thermos-
tat 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.
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 wa-
ter 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.
• 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 stor-
age tank or cylinder, regulator and pipework.
Reg 056
Diagram 24

17
SETTINGS
CHANGING GAS TYPE
Gas valve setting
All boilers are tested and factory set during manu-
facture. 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 maxi-
mum 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 de-
sired 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.
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 sys-
tem, 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 by-
pass 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 be-
tween 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
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
Reg 013
a
Diagram. 26
Diagram. 27
Reg 055
123456
SW1
ON DIP
Mec 121
A
B

18
To ensure the continued efficient and safe opera-
tion of the boiler it is recommended that it is
checked and serviced at regular intervals. The fre-
quency of servicing will depend upon the particu-
lar installation conditions and usage, but in gen-
eral 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 con-
trol 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.
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 re-
lease 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
Des 047
ROUTINE CLEANING AND INSPECTION
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 ex-
changer 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.
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 connec-
tion on fixing jig, see diagram 5.
• Open one or more hot water taps to drain boiler.
• Undo connecting nut from cold water inlet con-
nection to gain access to filter.
• Remove white filter from inlet connection.

19
REPLACEMENT OF PARTS
• Undo and remove screw securing spark genera-
tor 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 previ-
ously, undo and remove screw holding pump con-
nection 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 elec-
trical connector on ignition PCB. Leave ignition PCB
in place.
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, re-
connect pipe to inlet connection and tighten.
• Fully open isolating cock on cold water inlet con-
nection and check for leaks.
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.
ROUTINE CLEANING AND INSPECTION
To replace microswitch assembly exept SB models)
• Disconnect microswitch by pulling off plug.
• Unclip external controls connector from mount-
ing 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 con-
nection 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 se-
cure with screws.
• Fit replacement fan to boiler in reverse order to
removal making sure that mounting plate retain-
ing lugs are properly engaged into flue hood.
• Reconnect power supply and earth leads.
Important: Make sure that fan outlet is correctly fit-
ted into either the flue elbow for top outlet flue, or
the rear connector for rear outlet flue.
Before commissioning boiler, remove the two plas-
tic transit clips from replacement fan.
To replace air pressure switch
• Locate air pressure switch in upper left hand cor-
ner 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 re-
moval.
Important: Refit plastic tube to LEFT hand connec-
tor (marked P1).
To replace spark generator
• Locate spark generator on bracket to right hand
side of gas valve.
• Undo and remove screw securing lower termi-
nal cover to bracket and remove bracket.
• Disconnect four leads from spark generator.
Diagram 30
Sch 228
Hab 286
Diagram 29
microswitch on THEMA F 23 E

20
• 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 fol-
lows:
• Close isolating valves on flow and return connec-
tions 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 out-
let 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 re-
moval.
Note: Apply silicone grease to pump outlet con-
nection 'O' ring before assembly.
• Refit pump electrical connection.
• Open isolating valves on flow and return connec-
tions, refill, vent and pressurise boiler. Check for leaks.
To replace temperature/pressure gauge
• Drain down heating circuit of boiler only as de-
scribed 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 tempera-
ture/pressure gauge to lower front panel and re-
move gauge.
• Fit replacement gauge in reverse order to
removal.
REPLACEMENT OF PARTS
• Fit capillary of new gauge to front section using
new 'O' ring supplied.
• Open isolating valves on flow and return con-
nections, 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 pre-
viously.
• 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 re-
versing valve.
• Undo and remove large screw holding water
valve to back plate of reversing valve assembly,
see diagram 32.
Diagram 31
Cla 007
Des 054
Diagram 32