Keston C45 Installation And Servicing Instructions page 47

WD536 Chapter 7 : Replacement Of Parts
7.4.2 Boiler Flow and Return Thermistors (Fig. 5.7.2 item 47)
i)
ii)
iii)
iv)
v)
7.4.3 Cabinet Temperature Sensor (Fig 5.7.1 item 109)
i)
ii)
iii)
iv)
7.4.4 Flue Protection Thermostat (Fig. 5.7.2 item 46)
i)
ii)
iii)
iv)
v)
7.4.5 Water Pressure Switch (Fig. 5.7.2 item 48)
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
7.4.6 Main Control Box (Fig. 5.7.1 item 88)
i)
ii)
iii)
iv)
v)
vi)
7.4.7 Combustion Blower (Fig. 5.7.3 item 73)
i)
ii)
iii)
iv)
v)
vi)
Installation & Servicing Instructions
Isolate the appliance (Section 7.1)
Gain access (Section 7.2)
Remove the push on connectors from the thermistor taking note of the
correct positions.
Unclip the thermistor from the pipe.
Reassemble (Section 7.3)
NB: When fitting the new thermistor it is an advantage to smear a thin
film of heat sink compound between the thermistor and pipe.
This, combined with fitting the new thermistor tightly to the pipe,
ensures a good contact.
Isolate the appliance (Section 7.1)
Gain access (Section 7.2)
Remove the cabinet temperature sensor from the connector block by
slackening the retaining screws.
Reassemble (Section 7.3)
Isolate the appliance (Section 7.1)
Gain access (Section 7.2)
Remove the push on connectors from the thermostat taking note of the
correct positions.
Unscrew the two retaining screws, or nuts, and remove the thermostat.
Reassemble (Section 7.3)
NB: When fitting the new thermostat it is an advantage to smear a
thin film of heat sink compound between the thermostat and
plate. This, combined with fitting the new thermostat tightly to the
plate, ensures a good contact.
Isolate the appliance (Section 7.1)
Shut off the water supply to the appliance.
Gain access (Section 7.2)
Drain the system to below the level of the appliance using the drain off
tap at the base of the return pipe from the heat exchanger.
Remove the push on connectors from the water pressure switch taking
note of the correct positions.
Unscrew the pressure switch.
Reassemble (Section 7.3).
NB: Use a little jointing compound or PTFE tape on the thread.
Refill the system (See Section 4 - Commissioning).
Isolate the appliance (Section 7.1)
Gain access (Section 7.2)
Pull off the multi-pin connectors and HT lead away from the board.
Remove the three retaining screws securing the control block to the boiler
backframe.
Remove the control
Reassemble (Section 7.3)
Isolate the appliance (Section 7.1)
Gain access (Section 7.2)
Disconnect the two connector blocks from the combustion blower.
Unscrew the bolts securing the venturi (fig 5.7.3 item 81) to the inlet port
of the combustion blower.
Remove the four bolts securing the combustion blower (fig. 5.7.3 item 80)
outlet flange to the burner and remove the combustion blower.
Reassemble (Section 7.3)
NB: When reassembling inspect any gaskets for damage and replace
if necessary.
The Keston C45, C40P, C55 & C55P
Page : 42