35 replacement of components (REFER TO FRAME 43)
Gas Valve (refer to fig. 43.7, key 72)
1. Follow steps 1-2 of Burner Thermostat replacement.
2. Isolate the gas supply at the nearest gas cock to the boiler.
3. Remove the gas valve outlet pipe by unscrewing the two
union nuts holding it to the valve and injector.
4. Remove the gas/air pressure pipe and the electrical
connections to the gas valve.
5. Unscrew the union nut under the gas valve and withdraw
the valve upward.
6. Unscrew the connectors from the old valve and refit them
to the replacement valve using new ‘O’ rings.(provided)
7. Reassemble in reverse order and set the valve as
described in frame 31.
8. Reconnect the gas supply and check the operation of the
boiler.
Gas Injector (refer to fig. 43.9, key 57)
1. Follow steps 1-3 of Gas Valve replacement.
2. Unscrew the injector and discard.
3. Fit new injector ensuring the size is correct and the ‘O’
ring seal is in place.
4. Reassemble in reverse order.
5. Reconnect the gas supply and check the operation of the
boiler.
Air Restrictor (refer to fig. 43.9, key 59).
1. Follow steps 1-2 of Burner Thermostat replacement.
2. Swing the control panel away from the fan.
3. Remove the air hose to the heat exchanger by pushing it
upward to clear the fan body and then downward to
disconnect from the air/gas connecting piece.
4. Remove the air restrictor from the air/gas connecting piece.
5. Fit new restrictor and reassemble in reverse order
ensuring the tabs of the restrictor locate into the holes in
the air/gas connecting piece.
6. Check the operation of the boiler.
Burner Gasket (refer to fig. 43.9, key 50)
1. Follow steps 1-3 of Gas Valve replacement.
2. Remove the gas/air pressure pipe from the air/gas
connecting piece.
3. Remove the air hose to the heat exchanger by pushing it
upward to clear the fan body and then downward to
disconnect from the air/gas connecting piece.
4. Disconnect the electrical connections to the burner
thermostat.
5. Spring open the retaining clips at either end of the burner
cover.
6. Remove the burner cover and place to one side.
7. Remove old gasket and discard.
8. Fit new gasket and reassemble in reverse order.
9. Check the operation of the boiler.
Burner Plaque Assembly (refer to fig. 43.9, key 52)
1. Follow steps 1-6 of Burner Gasket replacement.
2. Remove gasket and diffuser plate.
3. Remove plaque assembly and discard.
4. Fit new plaque assembly and reassemble in reverse order.
5. Check the operation of the boiler.
Lower Access Cover Seal (refer to fig. 43.3, key 28)
1. Follow steps 1-7 of Fan replacement.
2. Disconnect siphon from lower access cover plate.
(see fig. 33.4)
3. Spring open the upper and lower retaining clips of the
lower access cover plate and pull downwards to remove.
4. Remove the damaged seal from the groove in the cover
plate and replace with the new seal ensuring it is not
stretched or twisted.
5. Reassemble in reverse order and check operation of the
boiler.
Heat Exchanger Guide Plate (refer to fig. 43.3, key 31)
1. Follow steps 1-3 of Lower Access Cover Seal
replacement.
2. Remove guide plate from heat exchanger and
discard.(see fig 43.3)
3. Fit new guide plate and reassemble in reverse order.
4. Check the operation of the boiler.
Sightglass (refer to fig. 43.3, key 22)
1. Follow steps 1-2 of Burner Thermostat replacement.
2. Remove the M6 screws retaining the sightglass assembly.
3. Remove the old sightglass and gaskets and discard.
4. Fit the new sightglass using the new gaskets provided.
5. Reassemble in reverse order and check operation of the
boiler.
Main Switch (refer to fig. 43.2, key 105)
1. Follow steps 1-2 of Burner Thermostat replacement.
2. From behind the control panel, push the black tab to
disengage the main switch.
3. From the front of the control panel, remove the switch
from its electrical connections.
4. Fit the new switch and push the assembly back into the
control panel.
5. Reassemble in reverse order and check the operation of
the boiler.
Temperature/Pressure Gauge (refer to fig. 43.2, key 104)
1. Follow steps 1-2 of Burner Thermostat replacement.
2. De-route the temperature and pressure sensing capillaries
from the flow pipe to the control panel.
3. From behind the control panel, unscrew the clamp nut
and remove the clamp.
4. Remove the gauge from the front of the control panel and
discard.
5. Fit the new gauge and reassemble in reverse order.
6. Check the operation of the boiler.
UBA or Control panel (refer to fig. 43.2, key 99)
1. Follow steps 1-2 of Burner Thermostat replacement.
2. Remove all electrical connections from the rear of the UBA.
3. Remove the main switch from the UBA (see Main Switch
replacement).
4. From the front of the control panel remove upper and
lower fixing screws and remove the UBA.
5. Fit the new UBA and fix with screws.
6. Cut rectangular hole in fascia to accept the main switch.
7. Refit main switch and replace all electrical connections.
8. Reassemble in reverse order and check the operation of
the boiler.
Maximiser SE
- Installation
28
