Manual - Formech 450DT V1.0 - 0317
29
Service / Repair
Replacing a Heating Element
> How to check a heating element
If you notice there is a cold area on heated plastics, it may be that a heating zone or heating element is
not working correctly. In either case the fi rst step is to check the wiring at the terminal block. It is not always
obvious that they are loose or disconnected.
1
- First, set all the zones to 70% and check for even heat and softening plastic when the heater is held over
the forming area with plastic sheet fi tted. Make a note of the area(s) where the plastic remains hard to
determine if it is a single element of entire zone. Allow the heater to cool completely before performing any
further checks.
2
- If an entire zone is not functioning, then the fi rst step is to check the wiring connections at the terminal
blocks. Ensure the machine is disconnected. Remove the top cover and check that the wiring is not loose or
has become disconnected for that particular zone. Remove the relevant terminal block covers to determine
this. If you are a qualifi ed electrical technician and conversant with electrical fault-fi nding techniques, then
refer to the circuit information at the rear of this manual. If you are uncertain then contact Formech for
service and advice.
3
- Resistances for heating zones and individual elements are scheduled in the electrical trouble shooting
section. Zones and elements can be verifi ed safely by checking the expected resistances.
4-
If an element is found to be broken or faulty using a resistance check and that corresponds with a cold
area, then it will require replacement. Refer to the following procedure:
1. Unplug the machine from the mains.
Bring the heater completely forward and
remove the 4 screws retaining the cover on
top of the heater.
2. Take the cover out.
Before any maintenance work is carried out the electrical supply must be locked in the OFF
position or the mains lead removed.
Only a qualifi ed electrical technician may work on any parts carrying mains voltage and should
be responsible for ensuring that the machine is in a safe condition before allowing services to be
restored.
