Expansion Vessel D.h.w; Expansion Vessel C.h - Potterton Puma 100 Installation & Service Instructions Manual

Component Replacement - Page 39
6.25

Expansion Vessel D.H.W.

(Fig. 34)
Isolate the electrical supply prior to this operation.
a. Remove the white front case and base panel.
See 5.1 & 5.2 in 'Routine Maintenance'.
b. Lower the control panel assembly by undoing the
securing screw at the top right hand side of the control
panel. Close the isolating valve on the cold water inlet
and open the lowest hot water tap. Remove the drain
screw on the isolating valve to completely drain the
appliance. Replace drain screw in isolator valve.
c. Remove the access panel to the left of the transformer.
Temporarily remove the transformer - See 6.31.
Note: It is not necessary to fully remove the top right hand
screw.
d. Release the vessel by unscrewing it from the inlet
manifold.
e. Carefully withdraw the vessel through the access hole.
Refit new component.
f. Re-assemble in reverse order, using a new sealing
washer. Open the isolating valve, and check for leaks.
6.26

Expansion Vessel C.H.

In the unlikely event of a failure of the C.H. expansion vessel
it is recommended that a new vessel be fitted exterior to the
boiler. It should be positioned on the C.H. Return pipe
(see Fig. 7) as close to the boiler as possible. If however,
the vessel must be replaced then the following procedures
may by used. Installations with vertical flue systems must be
fitted with exterior expansion vessels if the flue system can
not easily be raised a minimum of 50mm.
Note: It will simplify fitment of the vessel if a length of string
or flexible wire is attached to the end of the flexible pipe and
passed down the rear of the appliance through the back
panel hole and used as a guide to thread the pipe during
installation.
PROCEDURE 1. Horizontal flues only.
If the clearance above the boiler is greater than 300mm
proceed as follows:
a. Remove the white front case.
See 5.1 in 'Routine Maintenance'.
b. Lower the control panel assembly by undoing the
securing screw at the top right hand side of the control
panel.
c. Close the central heating flow and return isolating
valves, release the system pressure by operating the
pressure relief valve drain the appliance by removing the
drain plug on the underside of the pump manifold.
d. Undo the flexible pipe connection on the side of the
pump manifold and remove the grommet. Push the
flexible pipe through the hole in the back panel.
e. For rear outlet flues remove the flue elbow (4 screws)
f. Remove the top expansion vessel securing bracket
assembly (four screws) and slide the vessel (complete
with flexible pipe) upwards out of the appliance.
g. Remove the flexible pipe from the old vessel and refit
(using a new sealing washer) to the new expansion
vessel (at this stage the pre-charge pressure can be
easily checked and corrected if necessary. The pressure
should be at least equal to the system pressure at the
appliance).
h. Fit the new expansion vessel and re-assemble in
reverse order. Ensure that the vessel is located correctly
in the lower support bracket. Route the flexible pipe
through the hole in the back panel and refit grommet.
PROCEDURE 2
If the clearance above the appliance is less than 300mm
the appliance must be removed from the wall.
a. Remove the complete casing assembly (front, base and
sides)
b. Close all the isolating valves, reduce the pressures in
the appliance by operating the pressure relief valve and
opening the lowest hot water tap. Drain the remaining
water in the boiler by removing the drain screw under
the pump manifold (C.H.) and on the 15mm isolating
valve (D.H.W).
c. Lower the control panel assembly by undoing the
securing screw at the top right hand side of the control
panel.
d. Disconnect the input wiring noting positions of wires and
thread wiring out of control panel grommet/s.
e. Check the gas supply is isolated at the gas service cock,
(1/4 turn of square head), undo the gas cock union nut
and position nut clear of thread.
f. Undo the upper isolator valve connections on the C.H.
flow, return and Cold water inlet valves. Similarly
disconnect hot flow pipe, and pressure relief pipes.
g. Disconnect the flue elbow from the top of the appliance,
(4 screws), lift the flue elbow off the boiler connection
and rotate the elbow 180° to position the flue clear of the
appliance. If a vertical flue system is fitted it will require
raising approximately 50mm (2") to allow the boiler to be
lifted off its hanging screws.
h. Remove the bottom boiler securing screw then loosen
the appliance upper securing screws and lift the boiler
off the wall. Place unit face downwards on the floor.
Care should be taken not to damage the pressure gauge
or electronics.
j. Access can now be made to the expansion vessel. Undo
the flexible pipe connection to the vessel and remove
the screws retaining the upper expansion vessel bracket
to release the vessel from the appliance.
k. Fit a new expansion vessel and re-assemble in reverse
order, using a new sealing washer. At this stage it is
advisable to check the pre-charge.