Replacement Of Parts - Saunier Duval ISOMAX F 28 E Installation And Operating Instructions Manual

ROUTINE CLEANING AND INSPECTION
Flue system
• Check externally to make sure that flue is not
blocked
• Inspect flue system to make sure that all fittings
are secure.
Operation of fan
• Switch on electrical supply and turn on gas.
• Light burner by opening a hot water tap.
• Without sealed chamber cover in place, burner
should be automatically prevented from lighting
by air flow detection system.
• Refit sealed chamber cover.
• Check that fan operates when burner lights and
stops when it goes out.
Diagram 3
A
u
v

REPLACEMENT OF PARTS

For replacement of the following components it will
be necessary to remove boiler casing panels as de-
scribed in 'Routine Cleaning and Inspection'.
WARNING: Before commencing the replacement
of any component, isolate appliance from electri-
cal supply and turn off gas at service cock.
To replace domestic hot water thermistor
• Locate domestic hot water thermistor on hot wa-
ter flow pipe on right hand side of boiler adjacent
to gas valve.
• Unclip thermistor from pipe.
• Disconnect leads from thermistor.
• Fit replacement thermistor.
• Fit leads to replacement thermistor, the polarity
is not important.
To replace central heating thermistor
• Locate central heating thermistor on heating flow
pipe on centre of boiler.
• Unclip thermistor from pipe.
• Disconnect leads from thermistor.
• Fit replacement thermistor.
• Fit leads to replacement thermistor, the polarity
is not important.
To replace storage vessel thermistor
For this operation the boiler must be removed from
the wall.
• Drain down heating and hot water circuit of the
boiler only, as follows:
• Close isolating valves (q) and (v) on central heat-
ing isolating cocks (A) and (C), see diagram 3.
22
m
Cold water inlet filter
Drain down hot water circuit of boiler only, as fol
lows:
• Close isolating valve/throttle (m) on cold water
isolating cock, see diagram 3.
Note: This valve is closed when screwed fully clock-
wise.
• Open one or more hot water taps to drain boiler
circuit.
• Undo connecting nut from cold water inlet con-
nection.
• Clean and inspect filter, replace if necessary.
• With both filter and restrictor in place, recon-
nect connecting pipe to inlet connection and
tighten.
• Fully open isolating valve/throttle on cold wa-
ter inlet and check for leaks.
C
r
q
Note: These valves are closed when slots are at right
angles to direction of flow.
• Drain boiler by opening drain valves (r) and (u),
see diagram 3.
Note: It is not necessary to drain down entire heat-
ing system to carry out this work.
• Close isolating valve/throttle (m) on cold water
isolating cock, see diagram 3.
Note: This valve is closed when screwed fully clock-
wise.
• Open one or more hot water taps to drain boiler
circuit.
• Disconnect flue system.
• Disconnect boiler pipes onto fixing jig.
• Disconnect mains cable and any external con-
trols cables.
• Remove boiler from wall.
• From rear of boiler, disconnect domestic pipes
from storage vessel.
• Disconnect electrical connections from vessel.
• Unclip vessel from boiler frame and remove from
boiler.
• Slide off plastic strap and separate two halves of
vessel insulation.
• Locate thermistor at top of insulation.
• Replace thermistor in same position as old ther-
mistor.
• Refit vessel in reverse order to removal.
• Refit boiler onto fixing jig, tighten all connections
ensuring that all sealing washers are fitted before
tightening.
• Reconnect flue making sure that all joints are
properly connected.