28
COMpOnent aCCess
REMEMBER THAT HIGH VOLTAGES ARE EXPOSED WHEN THE CASE IS REMOVED AND THE UNIT IS
PLUGGED INTO THE POWER.
Index
page
Component
17
To drain the Alumina fluidising medium
18
To replace the Thermocouple
18
To replace the Heaters
18
To replace the Controller
19
To replace the Air Filters
19
To replace the Porous Plate
20
To replace the Flowmeter Tube
20
To replace the Fluidisation pressure switch (57)
20
To replace the Fuse
20
To replace the Triac/SSR
to drain the alumina fluidising medium
This is best done when the bath is cool as hot alumina can cause severe burns.
Ensure that the fluidisation air is turned off at the valve on the flowmeter (21), remove the drain cap (23)
situated at the bottom rear of the unit. CAUTION, CAP MAY BE HOT. If the flowmeter has not been
turned off and the unit is connected to the air supply, a jet of alumina will be released when the cap is
removed. Fit the drain extension tube. Avoid over tightening. The bath may now be drained by very
slowly turning on the fluidising air at the flowmeter until a steady flow of alumina is obtained. Hot
alumina should be drained into a well insulated container of suitable material to avoid fire hazards. When
the bath is empty remove the drain extension tube, clean the thread of the drain cap, and refit.
Note: Before replacing the thermocouple or the heaters the bath should be emptied of alumina, see para.
1 above. The air and electrical supplies must be disconnected at all times when servicing the system.
to replace the thermocouple
a) Remove the top panel (1) by removing the screw at the left hand bottom corner, push up and
pull out the panel.
b) Remove the three screws securing the front panel (5) along the upper edge. DO NOT DISTURB
SCREW WITH EARTH SYMBOL ALONGSIDE IT. Remove the knurled nut from the extraction
switch (22) and lower the panel.
c) Disconnect the thermocouple wires from the rear of the temperature controller (16) taking note
of the polarity for reconnection.
d) Slacken the thermocouple lock nut (52) back about 10mm. Unscrew the parallel bush (50) and
remove the thermocouple (51). Access may be improved by disconnecting the hose (31) from
the air mover (32).
e) Reverse the operation for replacing the thermocouple ensuring that it does not touch the
heater and that the sheath is clear of any electrical parts.
