Replacement Of Parts - Saunier Duval ISOFAST 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.
Cold water inlet filter
u
A
v
Diagram 3

REPLACEMENT OF PARTS

For replacement of the following components it will be
necessary to remove boiler casing panels as described
in 'Routine Cleaning and Inspection'.
WARNING: Before commencing the replacement of any
component, isolate appliance from electrical supply and
turn off gas at service cock.
To replace domestic hot water thermistor
• Locate domestic hot water thermistor on hot water
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 heating
isolating cocks (a) and (c), see diagram 3.
G
B
m
t
Drain down hot water circuit of boiler only, as fol
lows:
• Close isolating valve/throttle (m) on cold water iso-
lating cock, see diagram 3.
Note: This valve is closed when screwed fully clock-
wise.
• Open one or more hot water taps to drain boiler cir-
cuit.
• Undo connecting nut from cold water inlet connec-
tion.
• Clean and inspect filter, replace if necessary.
• With both filter and restrictor in place, reconnect con-
necting pipe to inlet connection and tighten.
• Fully open isolating valve/throttle on cold water in-
let and check for leaks.
r
D
C
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 heating
system to carry out this work.
• Close isolating valve/throttle (m) on cold water iso-
lating cock, see diagram 3.
Note: This valve is closed when screwed fully clock-
wise.
• Open one or more hot water taps to drain boiler cir-
cuit.
• Disconnect flue system.
• Disconnect boiler pipes onto fixing jig.
• Disconnect mains cable and any external controls ca-
bles.
• 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 ves-
sel insulation.
• Locate thermistor at top of insulation.
• Replace thermistor in same position as old thermis-
tor.
• Refit vessel in reverse order to removal.
• Refit boiler onto fixing jig, tighten all connections
ensuring that all sealing washers are fitted before tight-
ening.
• Reconnect flue making sure that all joints are prop-
erly connected.
F
21