Koehler K45850, Operation And Instruction Manual, Page: 7 / 10

K4585X Loss on Heat / Thin Film Oven
Operation and Instruction Manual
K4585X-Manual
- 6-
6 Troubleshooting / Service
6.1 Replacing the Digital Control Unit
1. Disconnect from the mains supply before
starting any work.
2. Remove the side panel at the left hand side of
the unit.
3. Carefully remove the terminal block on the
controller, taking note of the positioning of the
wires. This is done by pulling back the small
green locking tab and lifting the terminal block
off its pins.
4. Remove the plastic clip holding the controller
in position.
5. Withdraw the controller. Fit the new controller
and re-assemble in the reverse order.
6. Check all wiring before refitting the side panel.
6.2 Replacing the Overheat Thermostat
1. Follow steps 1 and 2 above.
2. From inside the chamber, locate the
thermostat bulb on the left hand side of the
chamber and remove the retaining clip. Take
note of the wires to the thermostat head and
remove the wires.
3. Remove the dial knob by first pressing out the
center cap which will reveal the locknut. Hold
the know tightly and slacken the locknut.
Gently tap the knob and remove it from the
spindle. Remove the two retaining screws on
the front panel and withdraw the thermostat
assembly. Fit the new unit in the reverse order.
Position the knob so that the arrow is
approximately at 30 degrees. Temporarily
tighten the locknut and follow recalibration
instructions.
6.3 Recalibration
1. Insert a suitable thermometer or thermocouple
via the top vent or attached to the motor shaft.
2. Set the digital control to 163°C and ensure that
the overheat dial is set to maximum.
3. Allow the temperature to stabilize.
4. Slowly turn the overheat dial down until the red
light illuminates. Increase the dial setting
upscale until the light just extinguishes. Ensure
that pointer on the dial lines up with the set
point (approximately 165°C). This can be
achieved by firstly gripping the knob tightly
and slackening the locknut. Ensure that the
knob is loose on the spindle (may require a
gentle tap to free it). Align the pointer to
165°C and tighten the lock nut. Refit the
center cap.
6.4 Replacing the Motor
Disconnect from the mains supply before starting
work!
1. Remove the table and table-connecting
shaft from the motor.
2. Remove the cowl from around the motor.
3. Disconnect the wires from the motor.
4. Remove the 4 retaining nuts holding the
motor in place.
5. Fit the replacement motor, ensuring that
the shaft is central in the top vent.
Reconnect the wires and refit the cowl.
7 Service
Under normal operating conditions and with
routine maintenance, the K4585X Loss on Heat /
Thin Film Oven should not require service. Any
service problem can be quickly resolved by
contacting Koehler’s technical service department
either by letter, phone, fax, or email. In order to
assure the fastest possible service, please provide
us with the following information.
Model Number:
Serial Number:
Date of Shipment:
8 Storage
This laboratory test instrument is equipped with
electrical components. Storage facilities should be
consistent with an indoor laboratory environment.
This testing equipment should not be subjected to
extremes of temperature and/or moisture.
This equipment was shipped from the factory in
a corrugated cardboard container. If long term
storage is anticipated, re-packing the instrument in
a water-resistant container is recommended to
ensure equipment safety and longevity.