4.3 Expansion Vessel, Pump &
Pressure Switch
Re-assemble all parts in reverse order.
1
.
C
hec
k
that the cap on the auto air vent is
open. Turn the 3 isolating valves OFF and
locally drain the boilers circuit by opening
the primary pressure relief valve.
2. Disconnect the flexible pipe at the union
below the pump.
3.
P
ull the expansion vessel forward and
spring the RH side panel slightly to enable
the vessel to be removed.
4.
C
hec
k
the pre-charge pressure of the
replacement vessel is between
1
.0 and
1
.2 bar before fitting.
5
. Reassemble in reverse order.
4.3a Pump - Head Only
1
. Drain the primary circuit and disconnect
the electrical plug from the pump motor.
2. Remove the soc
k
et head screws securing
the pump head to the body and draw the
head away.
3. Reassemble in reverse order.
4.3b Pump - Complete
1
. Drain the primary circuit and disconnect
the electrical plug from the pump motor.
2. Undo the two screws securing the body to
the pipe and manifold and draw the pump
forwards.
3. Unscrew the automatic air vent from the
pump body.
4. Examine the O ring seals on the return
pipe and manifold, replacing if necessary.
5
. Fit the air vent to the new pump body and
reassemble in reverse order.
4.3c Automatic Air Vent
1
. Drain the primary circuit and unscrew the
automatic air vent from the pump body.
2. Examine the O ring seal, replacing if
necessary, and fit it to the new automatic air
vent.
3. Reassemble in reverse order.
Expansion Vessel
Expansion Vessel
C
onnection
P
ipe
Spring
Washer
Soc
k
et Headed
Screw
P
ump Head
P
ump Body
Automatic
Air Vent
Fig.
18
36
© Baxi Heating UK Ltd 2015