Hot Surface Igniter And Flame Sensing Probe Positions - Hamworthy Wessex Modumax 100 series Installation, Comissioning And Servicing Instructions

Figure 10.2 - Hot Surface Igniter and Flame Sensing Probe Positions
10.3.2 Should a high pressure hose not be available,
the heat exchanger will have to be removed from the
module casing. Isolate the heat exchanger from the flow
and return water pipework and drain down. Remove all
fittings from the G1½ inlet nipples (including sensors
and pockets) and remove the safety valve (if fitted) or
¾" cap. Unfasten the 10 M8 nuts securing the water
connection sealing plates and the safety valve pipe
sealing plate, and remove all sealing plates and o-rings.
Each heat exchanger holds approximately 12-15 litres
of water (110-120) and weighs approximately 100kg. It
is recommended that a suitable lifting apparatus is used
to support the weight of the heat exchanger, an M12
lifting eye nut can be fitted to the M12 stud at the top of
the heat exchanger front plate for this purpose. Before
connecting the lifting equipment to the lifting eye, hang a
new heat exchanger to casing sealing gasket over the
lifting eye, with the adhesive side facing the boiler. This
will enable the new gasket to be fitted on re-assembly
without cutting it!
Remove the 6 M10 nuts that retain the heat exchanger
into the boiler module casing, and with the front end
supported slowly withdraw the heat exchanger until the
rear of the stainless steel baffles are visible. With the
rear of the heat exchanger resting in the body of the
HAMWORTHY HEATING LTD
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WESSEX MODUMAX 100 SERIES
boiler and the front supported by the lifting apparatus,
access is gained for removal of the stainless steel
baffles. Unhook the stainless steel springs and remove
the baffle plates to expose the finned tube bank. Wire
brush both sides of the baffles to remove any deposits.
Thoroughly wire brush the finned tubes and ensure that
all debris is removed from the centre of the heat
exchanger.
Remove the heat exchanger from the boiler body.
Remove the bolts and nuts securing the heat exchanger
front cover plate. Remove the bolts securing the heat
exchanger rear cover plate. Clean and de-scale all
surfaces of the heat exchanger tube header castings
and cover plates, and internal surfaces of the finned
tubes and water connection nipples. Chemical de-
scaling is preferred for the tube bank assembly.
Recommended solutions include 'Gamlen XD' blended
with 'Gamlen C.U.O.' inhibitor.
Note: Always follow the chemical manufacturer's
instructions to ensure correct application and safety.
Re-assemble the baffle plates by fitting one of the
stainless steel springs and inserting the baffles beneath
it, then fitting the second spring. Remove the existing
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