HAMWORTHY HEATING LTD
30
Wessex ModuMax
mk3
Boilers
500001308/C
from the casing by unfastening the 2 M6 nuts, to expose
the opening in the casing. The cleaning water and any
debris will exit the casing through this opening. On
completion ensure that the opening is clear of debris
and refit the condensate drain trap assembly, renewing
the gasket if required.
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 water flow and return connections
(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.
The boiler heat exchanger assembly is heavy, 97 &
116 weigh 100kg each & 147/196/254 weigh 130kg. 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
boiler and the front supported by the lifting apparatus,
access is gained for removal of the stainless steel
baffles. The silicon sealant between the baffle and the
end plates must be peeled away, before attempting to
remove the 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.
The heat exchanger tubes are stainless steel.
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.
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. When all the baffles are
Figure 10.2
-
Hot Surface Igniter and Flame Sensing Probe Positions
