Potterton Performa 28i Installation And Servicing Instructions page 34

Fig. 57
Pressure Gauge
Capillary
Gauge Retaining
Bracket
Fig. 58
Boiler
Chassis
Lock Nut
Pipe 'B'
Fig. 59
Pipe 'A'
Mounting Bracket
Spark Generator
Electrode Lead
34
Timer Cover
Pressure Gauge
Expansion Vessel &
Pre-Heat Store
Vessel Spigots
Fig. 60
12.0 Changing Components
12.15 Pressure Gauge (Figs. 57 & 58)
1. Drain the primary circuit and undo the nut on
the pressure gauge capillary.
2. Remove the timer cover and ease the timer
wiring aside. Undo the screws securing the
gauge retaining bracket.
3. Remove the bracket and gauge assembly.
Depress the barbs on the side of the gauge and
remove the retaining bracket.
4. Reassemble in reverse order.
12.16 Expansion Vessel &
Pre-Heat Store(Fig. 59)
1. To replace the expansion vessel and pre-heat
store it is necessary to remove the boiler from
the wall.
2. Drain the system and undo all gas and water
connections. Remove the flue elbow.
3. Lift the boiler off the wall plate and lay it on
either side on a clean flat surface.
4. Undo the unions on pipe 'A' and remove the
pipe (Fig. 59).
5. Undo the union on pipe 'B' connected to the
Retaining Clip
vessel (Fig. 59) and remove the locknut securing
Appliance Upper
the vessel spigot to the boiler chassis.
Cross Member
6. Undo the screws and remove the appliance
upper cross member. Slide the expansion vessel
and insulation out of the retaining clips.
7. Reassemble in reverse order using new
sealing washers. Fully recommission the
appliance and system.
12.17 Spark Generator (Fig. 60)
1. Pull the electrode lead off the spark
generator. Remove the screws and spring
washers securing the generator to it's mounting
bracket.
2. Pull the rubber shroud off the generator input
plug and disconnect the plug.
3. Reassemble in reverse order.