HAMWORTHY HEATING LTD
38
WESSEX MODU
MAX
100 SERIES
500001123/C
orientation, and secure firmly with the retained screws.
Check the setting of the gas supply pressure switch,
and adjust if necessary. Unfasten the single pozi pan
head screw to remove the cover if adjustment is
required. Replace the cover after setting the switch to
12.5mbar
.
Switch on the boiler module gas supply and check for
integrity of all joints using a proprietary leak detector.
Refer to Figure 7.1 if necessary for valve integrity check
procedure. Switch on the boiler module electrical power
supply and ensure gas valve operation is correct and
safe before continuing.
Re-light the boiler module. For correct settings and
procedures refer to
Section
8.0
Commissioning The
Boiler
.
11.5 Combustion Fan
Part No. 533704007
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
Disconnect the fan power supply and control leads from
the fan. Remove the 6 M5 screws securing the gas
valve and gas feed pipe to the air inlet box. Support
the weight of the assembly and put to one side on
the flexible gas supply hose.
Remove the 3 M4 hex head screws, nuts and washers
fastening the venturi to the air inlet box. Remove the 4
M5 screws securing the air inlet box to the fan body.
Disengage the air inlet box from the air inlet duct and
remove from the fan. Remove the 4 M5 screws
securing the fan outlet to the burner flange and remove
the fan.
Fit the replacement in reverse order, and if required
replace any seals or gaskets.
Note:-
After re-making any gas or combustion circuit
joint/connection, an integrity check is recommended to
ensure safety.
11.6 Venturi
Part No. 532418002
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
Isolate the boiler module gas supply by closing the gas
service valve. Remove the 6 M5 screws securing the
gas valve and gas feed pipe to the air inlet box.
Support the weight of the assembly and put to one
side on the flexible gas supply hose.
Remove the 3 M4 hex head screws, nuts and
washers fastening the venturi to the air inlet box,
ensuring correct orientation.
Fit the replacement in reverse order, and if required
replace any seals or gaskets.
Note:-
the venture is supplied with an air inlet ring,
the position of which is factory set. Do not adjust the
position of the ring.
11.7 Burner
Part Number 533301019
Disconnect the H.S.I. and flame probe connectors from
the respective probes. Disconnect the fan power supply
and control leads from the fan taking care with the latch
on each connector.
Unscrew retaining screws and remove the electrical
plug from the gas valve.
Check that the gas service valve is closed, then undo
the lower connection union on the flexible hose (at gas
control valve inlet elbow). Remove the 6 M5 screws
securing the gas valve and gas feed pipe to the air
inlet box. Support the weight of the assembly and
put to one side on the flexible gas supply hose.
Separate the burner fabrication from the fan and air inlet
box assembly.
Remove and inspect H.S.I. and flame probe, ensure
they are free from debris or deposits. Test resistance
value of H.S.I. if above 110 ohms (cold), replace with a
lower resistance unit. Check respective positions – See
Figure 13.2.
Note:-
The H.S.I. element is very fragile.
A damaged or cracked burner should be replaced.
Replace components in reverse order using new
gaskets.
11.8 Ignition Transformer
Part No. 533901441
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls.
Unplug the electrical connections to the transformer
noting the orientation and relative positions. Remove the
two pozi pan head screws securing the transformer to
the control panel and withdraw. Fit the replacement unit
in reverse order. Re-light the boiler and check for correct
operation.
11.9 Main Control - LMU
Part No. 533901436 - M110
Part No. 533901452 - M120
Ensure that the boiler module electrical power supply is
isolated before removing the front cover and gaining
access to the controls. Also ensure that all other
supplies, particularly to the volt free contact outputs, are
also isolated.
