13.0
Changing Components
39
© Baxi Heating UK Limited 2005
13.3
Flowswitch
(Fig. 47)
1. Drain the boiler (see Section 13.1 paragraph 2 & 3).
2. It may be necessary to remove the expansion vessel
(see Section 13.5).
3. Remove the clip securing the flow pipe to the
flowswitch.
4. Remove the two screws securing the flow switch to
the boiler.
5. Disconnect the inline electrical connection.
6. Remove the flowswitch.
7. Fit the new flowswitch and reassemble in reverse
order.
8. Recommission the boiler and check the inhibitor
concentration (see Section 6.1 and 10.1).
13.4
Flow or Return Temperature
Thermistors and Safety Thermostat
(Figs. 48 & 49)
1. The procedure is the same for both the thermistors
and the safety thermostat, although the components are
not interchangeable.
2. Remove the electrical connection from the
component.
3. Unscrew the component from the pipe.
4. Fit the new thermistor or safety thermostat and
reassemble in reverse order.
13.5
Expansion Vessel
(Fig. 50)
1. Drain the boiler (see Section 13.1 paragraph 2 & 3).
2. Loosen the securing screw at the base of the
expansion vessel.
3. Whilst supporting the vessel undo the expansion
vessel connection and retain the sealing washer.
4. Remove the expansion vessel.
5. Fit the new expansion vessel and reassemble in
reverse order.
13.6
Re-pressuring Expansion vessel
1. The charge pressure is 1.0 bar.
2. Close the central heating flow and return isolating
valves.
3. Drain the boiler (see Section 13.1 paragraph 2 & 3).
4. The “Schraeder” valve is positioned centrally at the
side of the appliance. Pressurise to 1.0 bar.
5. Open the isolating valves and recharge the system to
between 1.0 bar and 2.5 bar. Vent the system as
necessary.
Fig. 47
Flowswitch
Clip
Fig. 48
Fig. 50
Flow Pipe
Electrical
Connections
Expansion Vessel
Expansion Vessel
Securing Screw
Flow Thermistor (Red Body)
Safety Thermostat (Black Body)
Expansion Vessel
Connection
Return Thermistor
(Red Body)
Fig. 49
