7. REPLACEMENT OF PARTS
CONTENTS
7.0
GENERAL
7.1
PRECAUTIONS
7.2
ACCESS
7.3
REPLACEMENT PROCEDURE
7.4
ELECTRICAL COMPONENTS
7.4.1
CONTROL PANEL
7.4.2
BOILER FLOW & RETURN THERMISTORS
7.4.3
CABINET TEMPERATURE SENSOR
7.4.4
FLUE PROTECTION THERMOMSTAT
7.4.5
WATER PRESSURE SWITCH
7.4.6
MAIN CONTROL BOX
7.4.7
COMBUSTION BLOWER
7.4.8
GAS CONTROL VALVE / VENTURI ASSEMBLY
7.5
SPARK IGNITION/FLAME DETECTION ELECTRODE
7.6
BURNER
7.7
HEAT EXCHANGER
7.8
CONDENSATE TRAP
7.9
PUMP
7.0
GENERAL
The following must always be carried out by a competent/qualified person.
7.1
PRECAUTIONS
i)
Always switch off the mains electricity supply and disconnect the plug at the
isolating switch and socket. (If a switch only is used then remove the fuse.)
ii)
Gain access to the appliance (Section 7.2) and turn off the gas supply at the
appliance service cock.
WARNING :
Parts of the boiler internal wiring will remain live even after setting
the User Controls to Standby. Shut off the power supply at the
isolating switch before working on the appliance.
7.2
ACCESS
i)
Remove the cabinet by removing the screws to the top and bottom of the cabinet.
7.3
REPLACEMENT PROCEDURE
i)
Always replace in the reverse order unless otherwise stated.
ii)
Electrical connections must be remade in accordance with the Electrical Wiring
Diagram (Section 5.5).
iii)
Test the soundness of any gas carrying or water carrying joint broken during the
service procedures.
7.4
ELECTRICAL COMPONENTS
7.4.1
Control Panel (Fig. 5.7.1 item 106)
i)
Isolate the appliance (Section 7.1)
ii)
Gain access (Section 7.2)
iii)
Remove the user control cover by removing the four retaining screws (Fig
5.7.1, item 90).
iv)
Disconnect the Control Panel by unplugging the ribbon cable connection
block.
v)
Disconnect the potentiometers (Fig 5.7.1, item 119) by unplugging the
cable connection.
vi)
Reassemble (Section 7.3)
vii)
Check for correct operation of the Control Panel.
WD536 Chapter 7 : Replacement Of Parts
The Keston C45, C40P, C55 & C55P
Installation & Servicing Instructions
Page : 41