Keston 50 - GC Installation And Servicing Instructions page 49

WD50/2/1997 Chapter 7 : Replacement Of Parts
7.4.7 Air Pressure Switch (Fig. 5.7.1 item 110)
i) Isolate the appliance (Section 7.1)
ii) Gain access (Section 7.2)
iii) Remove the push on connectors from the air pressure switch taking note
of the correct positions.
iv) Disconnect the union to one plastic tube connection and pull off the
second plastic tube from the air pressure switch.
v) Unscrew the two screws mounting the air pressure switch body to the
boiler casing.
vi) Reassemble (Section 7.3)
NB:
7.4.8 Combustion Blower (Fig. 5.7.3 item 80)
i) Isolate the appliance (Section 7.1)
ii) Gain access (Section 7.2)
iii) Remove the cover plate to the electrical connections on the blower motor
by removing the four retaining screws.
iv) Disconnect the wires to the combustion blower taking note of the correct
positions.
v) Remove the allen screws fixing the air intake pipe flange and the gas/air
mixture pipe flange to the blower.
vi) Undo the two nuts securing the combustion blower base plate to the
cabinet base and lift out the combustion blower.
vii) Unscrew the three bolts fixing the base plate and anti-vibration mounts to
the combustion blower.
viii) Reassemble (Section 7.3)
NB:
ix) Reset the gas rate (See Section 4 - Commissioning)
7.4.9 Gas Control Valve (Fig. 5.7.3 item 95)
i) Isolate the appliance (Section 7.1)
ii) Gain access (Section 7.2)
iii) Remove the cover concealing the electrical connections on the front of
the gas valve.
iv) Remove the push on connectors exposed taking note of the correct
positions.
v) Remove the push on connectors to the gas low pressure switch taking
note of the correct positions.
vi) Remove the earth connection to the side of the gas valve.
vii) Remove the four allen bolts securing the gas inlet flanged connections to
the gas control valve.
viii) Undo the four bolts fixing the base of the gas control valve to the gas
outlet block.
ix) Remove the gas valve.
x) Unscrew the gas low pressure switch at its connection to the gas control
valve body.
xi) Reassemble (Section 7.3)
xii) Reset the gas rate (See Section 4 - Commissioning)
Installation & Servicing Instructions
Ensure the yellow/green earth connection tag is securely fixed
behind the lower mounting screw.
When reassembling inspect any gaskets for damage and replace
if necessary.
Page : 46
The Keston 50, 60 & 80 Condensing Boilers