HAMWORTHY HEATING LTD
24
WESSEX 100 M
500001080/F
14.3 Control Thermostat Renewal, High/Low
Part Nos. 339009345 or 533901178
Alternative thermostat manufacturers may be
used in the Wessex boiler controls assembly.
However, the fitting and wire spade connections
are physically identical as are the two
thermostats for High and Low firing. The terminal
identification may well be different from that
shown on the wiring diagram inside the fascia.
Please refer to the thermostat to ensure correct
electrical connections are made and correct
operation is obtained.
To replace the thermostat the following procedure
must be followed.
NOTE!
Record existing
temperature setting of thermostat for reference
before removal. Remove the clip securing the
thermostat phials in the pocket and carefully
remove thermostat phials. Drop down fascia to
reveal controls section. Remove the 'push on'
spade connectors from the thermostat body
noting position of coloured cables. Pull off the
control knob and remove bezel. (
Note!
This may
be retained by the two M3 screws holding the
thermostat to its bracket). Check whether screws
are of different type/length for re-assembly
purposes before removing them. The thermostat
body can now be removed by gently feeding
capillary through the controls bulkhead. Fit the
new thermostat and ensure the capillary is
correctly located within the boiler pocket and
close fascia. Do not force the bulb into the pocket
by placing undue stress on the capillary. Refit
the clip securing the thermostat phials in the
pocket.
Run the boiler and turn the thermostat up and
down to check for correct operation. Set
thermostat to previously noted setting.
14.4 Temperature Limiter (Limit Stat) Renewal
Part Nos. 533901179 or 339011044
The temperature limiter renewal procedure
follows that of the control thermostat with some
minor differences. These are as below:-
Remove the 'push on' spade connections from
the temperature limiter body noting position of
coloured cables. Remove plastic cover (if fitted)
and unscrew holding nut to detach temperature
limiter from housing. Gently feed the capillary
back through the controls bulkhead. Check the
operation of the device by carefully applying a
heat source to the bulb. Set temperature limiter to
100°C (for high temperature option, set to a
maximum of 120°C). Re-assemble temperature
limiter into controls housing ensuring correct
cable notation. Refer to thermostat diagram if
terminal identification differs from those given in
Figure 9.1 (p13).
14.0 REPLACEMENT OF FAILED COMPONENTS
There are a number of components listed below
which can be replaced simply and quickly by
following the given procedure. In each case the
operation of each replaced component must be
checked by carrying out the appropriate part of
the commissioning procedure. See
Section
11.0: COMMISSIONING & TESTING
(p15).
NOTE: Isolate all electrical supplies to the
boiler and turn off the gas supply before
removing controls cover and commencing any
servicing or component exchange procedure.
(For the replacement and service of items
outlined in section 14, it maybe advantageous to
swing the control panel up as described in
Section 13.2 clause 2) (p20).
14.1 Hot Surface Igniter and Flame Probe
Assembly
Part Nos. 563801006 & 533805010
Note :- the igniter and probe ceramics are
very fragile.
Reference to Figure 14.1 (p25)
shows position of the igniter and flame probe
assembly. Unplug the igniter from the harness
and remove the single socket cap head screw
securing the igniter to the burner flange. Carefully
withdraw the igniter, renew as required and
generally remove any loose sooty deposits, clean
as required. Replace igniter and secure socket
cap head screw holding the igniter to the burner
flange. Disconnect the flame sensing probe
connection, remove the single socket cap head
screw securing the probe to the burner flange
and carefully withdraw the probe. Renew as
required and generally remove any loose sooty
deposits, clean as required. Ensure positions of
components are as recommended in Figure 14.1
(p25). Note – do not remove both securing
screws as the separate flange and Mica sight
glass will become detached.
14.2 Air Pressure Switch
Part No. 533901334
The same type of pressure switch is used to
monitor the operation of the fan in both High and
Low fire operation. The pressure switches are
mounted in the control panel and are identified -
HI/LO.
Note and disconnect the electrical connections.
Note and remove the flexible hoses from the
switch, undo the 2 screws attaching the switch to
its mounting bracket on the rear of the controls
panel and withdraw the switch.
Replace the switch in the reverse order and set
to the required setting - see Figure 14.2 (p25).
Summary of Contents for Wessex 100 M100
Page 39: ...Notes ...
