Control Fuse Replacement; Heating Element Measuring System - Thermo Scientific STF55433 Installation And Operating Manual

| Maintenance & Cleaning
Chapter 10
|
10-86
305435H03
WARNING : Disconnect furnace from main power before attempting any
maintenance to furnace or its controls.
Remove the five screws located on the control back panel.
1. Swing the panel down to the horizontal position.
2. Locate the solid-state relay on the back panel (refer to Figure 12"Control" ).
3. Note the terminal connections of the relay wires and label them for reattachment.
Remove the wires from the terminals of the relay.
4. Remove the mounting screws from the relay.
5. Replace the relay and reconnect the wires.
6. Reassemble the unit.

Control Fuse Replacement

WARNING : Disconnect furnace from main power before attempting any
maintenance to furnace or its controls.
To replace the fuses located on the control back panel, complete the following steps:
1. Press on the red fuse button and release (refer to Figure 12"Control" ).
2. Slide the fuse button out of the control back panel.
3. Pull the fuse out of the button and insert a new 3 amp fuse.
4. Replace the fuse button and press until the button is firmly seated in the panel.

Heating Element Measuring System

CAUTION : Measurements of the live electrical system while the furnace is at high
temperatures are necessary to complete these steps.
A high degree of safety practices MUST be adhered to during this procedure. Including
but not limited to sufficient space to safely access the electrical enclosures while at high
temperatures, protective clothing for high temperatures & electricity and electrically
insulated test probes with clips.
1. Review this entire Procedure BEFORE starting.
2. Remove Element Terminal Covers from the Furnace Cabinet.
3. Identify the element set(s) and terminal positions.
1500°C Tube Furnace