Technical data

46
4000123924-2
20 Replacement of Parts
Diagram 20.1
To Drain the central heating circuit
• Open drain valve fitted at the lowest point in the system.
• Allow air into the system by opening a radiator bleed screw or the boilers drain
valve (f).
(F30E/F35E Only) To Drain the Domestic hot water circuit
• Close boiler isolating valve (b).
• Turn on one or more hot water taps.
To Drain the boiler
• Close isolating screws on the isolating valves (a), (b) and (c).
• Open the boiler drain valve (f).
Note: Isolating cocks water and gas are shown in the: OFF positionF30E/F35E shown
(f)
BOILER
DRAIN VALVE
(e)
(d)
(a)
HEATING
RETURN
COLD WATER
INLET
(F30E/F35E Only)
HEATING
FLOW
DOMESTIC HOT
WATER OUTLET
(F30E/F35E Only)
GAS SERVICE
COCK
(c)
(b)
Diagram 20.2
9550
F30E/F35 E shown
CENTRAL HEATING
THERMISTOR
IMPORTANT INFORMATION
WARNING: Before commencing the replacement of any
component, isolate appliance from electrical supply and turn
off gas at service cock.
Replacement of parts must be carried out by a competent
person.
When replacing components it may be necessary to renew
sealing washers, gaskets and 'O' rings. If new ones are
supplied with replacement components they must be used.
All parts are replaced in reverse order to removal.
If any gas-carrying components are disturbed, removed or
replaced it will be necessary on completion of assembly to test
for gas soundness and purge in accordance with the current
issue of BS6891 or in IE, the current edition of I.S.813 "Domestic
Gas Installations".
20.1 Central heating thermistor
Before starting refer to the front of Section 20 Important
information.
• Remove the front panel, refer to Section 17.3.
• Lower the control panel, refer to Section 17.4.
• Locate central heating thermistor on heating flow pipe on
centre of boiler, see diagram 20.2.
• Unclip thermistor from pipe.
• Disconnect electrical connections from thermistor.
• Fit electrical connections to replacement thermistor and fit
thermistor to pipe. The polarity is not important.