Solid- State Relay Replacement - Thermo Scientific STF55433 Installation And Operating Manual

1500°C Tube Furnace
1. Disconnect main power and switch the circuit breaker to the OFF position.
2. Remove the two screws located on each side of the furnace near the lower front. Pull
the control panel forward and swing to the horizontal position to access the module.
NOTE
If the control panel does not detach easily, insert the blade of a small screwdriver
between the panel and the side of the control and gently pry the control panel out.
3. Note the terminal connections of the wires and label them for reattachment. Remove
power input and output wires from the back of the control module. Observe polarity
for the thermocouple lead wire. Red is always negative.
4. Unscrew and remove the mounting brackets from the module.
5. Remove the module.
6. Install the replacement instrument by reversing the above procedure.
7. Slide the bottom edge of the control panel under the lip inside the control and gently
push the panel back into position.
8. Replace the screws.
NOTE The top of the control panel is recessed at a 5° angle.

Solid- State Relay Replacement.

Figure 12. Control
Refer to the "Troubleshooting" Section for relay testing. If the solid-state relay is
inoperable, complete the following steps to replace the relay (refer to Figure 12"Control" ):
Maintenance & Cleaning |
Chapter 10
305435H03 | 10-85