Instruction manual

IMP IMP/P Hot Runner Controllers Instruction Manual
60-second interval during start-up. It
takes 60 seconds to detect “No heat”
when power is first turned on in
closed-loop mode.
If CompuStep is active, the test is not
performed until after CompuStep is
finished (5 minutes). When “No heat”
alarm is detected, output power is cut off.
What to do:
a. Try resetting the controller by
turning its AC power OFF and then
ON.
b. If “No Heat” persists, then the problem
could be one of the following.
1) Open heater or load.
2) Thermocouple shorted. Switch to
manual mode to override this
condition.
3) Load circuit open. This can be
caused by an open power cable,
an open connector or a failed triac
in the controller. Exchange the
module with a known good module
to eliminate suspect triac or module.
4) Slow heater. Use higher power
heater or operate in manual mode
until setpoint is achieved.
5) Thermocouple too far away
from heat source that causes less
than 2°F (1°C) rise in 60 seconds
due to thermal lag. Move thermo-
couple as close to heater as
possible or use heater with built
in thermocouple.
6) To defeat “No Heat” circuit, if not
used or required, remove jumper
J4 and that circuit will no longer
be active.
seconds, then re-examine the
temperature by switching mom
entarily to closed-loop mode. Repeat
this procedure until the temperature
is the same in either automatic or
manual control.
Faults
1. Over temperature alarm:
A constant over temperature alarm is
most likely caused by a shorted triac
in the controller or incorrect or
shorted mold wiring. Switch module
power off as quickly as possible and
replace controller or correct wiring
error. Check for thermocouple or
heater cross wiring.
2. Under temperature alarm:
Under temperature alarm is normal
during system start-up before the
setpoint is reached. If under
temperature persists, a No heat
fault will occur.
3. Thermocouple open or reversed:
If any T/C fault is detected during
closed-loop operation, the output
power will be cut off. If it is necessary
to apply power to the load during a
T/C fault condition, the controller can
be switched to manual mode. The
output power will be a function of the
manual control knob setting. Since
the controller is now operating in
open-loop mode, extreme care must
be taken when adjusting to prevent
excess output power that would
overheat the load.
4. No heat:
The IMP series controller has
included in its microprocessor a
program that detects that the
temperature is not rising as it should
in response to full power output. “No
heat” is defined as the condition
under which the temperature does
not increase more than 2°F during a
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