HAMWORTHY HEATING LTD
WESSEX-HE 200 BOILER
500001008/K
15
b)
Disconnect leads to spark electrode and flame
probe by pulling their connectors from the pilot
assembly.
c)
Loosen and remove gas pipe from between the
pilot burner and pilot solenoid valve. Blow
through and clean.
d)
Unplug the Din Connector to the pilot solenoid
valve by loosening securing screw.
e)
Un-plug the Main gas valves wiring assembly.
f)
Loosen and remove the two Bundy Tubes that
connect the differential pressure switch to the
fan/fan extension.
g)
Remove the clip and withdraw both thermostat
bulbs from pocket.
h) Unscrew the four M6 nuts securing the
complete assembly to the front tube plate cover
casting and withdraw the assembly from the
module, lifting upwards to allow the fan housing
to clear the gas inlet pipe.
i)
Remove stainless steel orifice plate/insert and
its cork gaskets.
j)
The burner can now be withdrawn from inside
the heat exchanger by first removing the M5
screw and washer, then tap lightly on the
flange to loosen the burner. The centre cone
can be gripped with pliers to facilitate
withdrawal.
13.2.3
Clean the burner by gently brushing inner and
outer surfaces, tap burner flange firmly downwards on
a wooden block to eject particles of dust and debris.
Check circular cork gasket for soundness and renew
if necessary. Clean burner insert in a similar manner.
Replace burner in module. (Closed end of burner
must locate in recess in module rear tube plate, this
will be indicated when the flanged end of the burner is
flush and square with the front header casting.)
Ensure the "Top" marking on the flange is correctly
positioned. Check rectangular cork gaskets for
soundness and renew if necessary. Position one
gasket over studs and refit the burner insert.
Complete by fitting second gasket.
13.2.4
The fan/mixing chamber and controller
assembly may be removed to bench for cleaning:
a)
Un-plug fan wiring and remove fan casing/
extension piece from fan and motor mounting
plate by removing four 'Pozidrive' screws (one
may already have been removed with cable
clamp), holding fan motor and controls bracket
and work loose taking care not to damage
rubber gasket, and without putting any strain
on cable connections or wiring loom.
b)
Gently brush fan blades if necessary to remove
any dust accumulation.
c)
Blow through the differential pressure switch
Bundy pipes to check that they are clear when
they have been detached from the pressure
switch, to prevent damage to the diaphragm.
d)
Gently brush both sides of swirler (located
between fan discharge flange and extension
duct) to remove any dust accumulation.
NOTE!
Exercise extreme caution when cleaning
swirler as it must not be damaged or altered in any
way.
Do not
attempt to remove it from its location.
13.2.5
Remove the pilot burner assembly by
unscrewing the two M5 screws and withdrawing from
heat exchanger. Check pilot assembly. If the spark
electrode shows signs of oxidation or is bent, it
should be renewed. Check spark gap is set to 2-3
mm. (See Figure No. 10). Check injector in brass
fitting is clean. Check spiral stabiliser for wear and
renew complete unit if necessary.
13.2.6
Check flame probe for signs of oxidation or
bending. Renew if required. Length of metal rod
should be 98mm minimum. Refit pilot assembly.
13.2.7
Re-assemble fan/mixing chamber and
controller assembly to boiler in reverse procedure to
that given in paragraph 13.2.2. Use colour code
shown on wiring diagram (Figure No. 5) to facilitate
reconnection of electrical leads.
13.2.8
Ensure module manual gas valve is off, check
the programmed sequence as described in paragraph
11.4/11.5 on initial commissioning in Commissioning
and Testing section. Test all gas joints broken or
disturbed for soundness before firing.
13.2.9
Remove the two filter pads from the burner
tray and the front of the module controls cover.
Remove dust by shaking or washing in soapy water,
rinsing and drying. If the contaminants cannot be
substantially removed - discard and fit new filters.
13.2.10
Carry out combustion check by testing the
flue gas CO
2
and CO levels; typical values are given
in paragraph 11.5.2. Replace module cover, tighten
retaining screw and fit closing plate if part of HE
County model.
13.3 Two Year Service
a)
NOTE:
It is advisable to have at hand a tube
of silicone rubber sealant or self adhesive
silicon rubber strip in addition to other usual
gasket materials.
13.3.1
Repeat annual service as describe in
paragraphs 13.2.1 to 13.2.6 inclusive, but do not
reassemble any items to the boiler.
13.3.2
a) For the Wessex-HE 200 remove and retain the 6
M5 'Pozidrive' screws retaining the boiler insulation
panels, taking care to note the order of re-assembly.
(The HE County panels are not screwed but are
retained on brackets and can be lifted off). Lift the
top insulation panel clear of the boiler and then
