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Service\Repair Formech FM660
Replacing a heating element - continued
Disconnect the electrical mains supply.
Bring the heater completely forward.
Remove the self tapping screws securing the slotted heater cover and place to one side with
the cover. At this stage check that the wiring terminal block connections and the simmerstat
connectors at the front of the heater are fully tightened and that the fault was not merely a loose
connection or a disconnected clip.
Remove the cap from the terminal block associated with the faulty element, loosen the terminal
block screws and remove the element leads and insulation sleeves.
Remove the retaining clip holding the faulty element placing hand underneath heating element
to prevent it from falling. Remove the element.
Push new element into hole and fix spring & clip from top.
Slide on the insulation sleeves, replacing with new if perished or damaged. Ensure that the
connections are fully tightened and correctly wired.
Replace the terminal block cover and check that no cabling is touching any metal parts.
Replace the slotted heater cover and fit the self tapping screws.
Auto-levelling system
This machine is fitted with an automatic sheet levelling system. An optical sensor directs a beam of
infrared light across the machine; a ‘honeycomb’ reflector receives this light and shines it back to the
sensor. If the beam is broken air is pumped onto the base of the machine under the plastic lifting it until
the reflected beam is re-established.
When the plastic is heated it begins to sag and cuts the beam, the compressed air lifts the plastic until it
has cleared the beam. The air is then shut off until the plastic sags again. The intervals between the air
turning on & off may be very short.
The alignment between the optical sensor and the reflector is finely adjusted. It may require re-
adjusting if the machine has been transported or used roughly.
If the heater is left for any time over the forming area (without plastic clamped in) the reflector
may become distorted. The sensor may fail if it is exposed to high temperatures.
The optical sensor is located under the top-frame on the left-hand side. The reflector is opposite.
When the sensor is in the ‘beam received & returned unbroken’ state only the green LED will light.
When the beam is broken the red & green LED’s will light. No other combination will work properly. If
the above LED’s light at the correct time but the Auto-Level does not work properly then either the
beam is shining too low or too high. Alternatively the pneumatic system is failing.
