Saunier Duval THEMA F 23 E Installation Instruction
21
REPLACEMENT OF PARTS
• Push water valve back to disengage it from re-
versing 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 assem-
bly from boiler.
• Undo and remove heating return connecting
pipe and hose from rear of reversing valve assem-
bly. Fit hose to replacement reversing valve assem-
bly.
• Fit replacement reversing valve into boiler in re-
verse 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 con-
nections, refill, vent and pressurise boiler. Check for
leaks.
versing 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 assem-
bly from boiler.
• Undo and remove heating return connecting
pipe and hose from rear of reversing valve assem-
bly. Fit hose to replacement reversing valve assem-
bly.
• Fit replacement reversing valve into boiler in re-
verse 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 con-
nections, refill, vent and pressurise boiler. Check for
leaks.
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 sec-
tion.
• 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 sec-
tion 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 sec-
tion 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 sec-
tion 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 con-
nections, refill, vent and pressurise boiler. Check for
leaks.
• Remove pressure gauge capillary as described
previously.
• Remove pipe connections from either side of
reversing valve front section, refer to previous sec-
tion.
• 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 sec-
tion 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 sec-
tion 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 sec-
tion 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 con-
nections, refill, vent and pressurise boiler. Check for
leaks.
To replace loss of water switch
• Drain down heating circuit of boiler only as de-
scribed in 'To replace pump'.
Note: It is not necessary to drain entire heating cir-
cuit 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 re-
versing valve assembly.
• Pull switch out of reversing valve assembly, see
diagram 33.
• Fit replacement switch in reverse order to re-
moval, 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 con-
nections, refill, vent and pressurise boiler. Check for
leaks.
• Drain down heating circuit of boiler only as de-
scribed in 'To replace pump'.
Note: It is not necessary to drain entire heating cir-
cuit 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 re-
versing valve assembly.
• Pull switch out of reversing valve assembly, see
diagram 33.
• Fit replacement switch in reverse order to re-
moval, 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 con-
nections, 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 pre-
viously.
• Unscrew connecting nut from cold water inlet
connection, second from left on fixing jig. Keep fil-
ter 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.
models)
• Drain down hot water circuit of boiler only as
described in 'Routine Cleaning and Inspection'.
• Remove microswitch assembly as described pre-
viously.
• Unscrew connecting nut from cold water inlet
connection, second from left on fixing jig. Keep fil-
ter 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.
Diagram 33
Sec 059
Diagram 34
Cla 007