Chapter 4 – Smoke Control Section, Page 4-24__________________________________________________
Smoke Control – Troubleshooting (Cont.)
Testing Plunger Safety Switch
1.
There is one or more Plunger Safety Switch located in the Electrical Compartment (Refer to Figure
4-
17-1 and 4-24-1)
. The Plunger Safety Switch, when released by opening the Electrical Compartment
door, shuts off the power to the power supply transformer and bleeds power from the transformer,
by the Grounding Disc making contact with the brass grounding screws (Refer to
Figure 4-17-1, 4-24-
1 and 4-24-2).
There are two potential areas that can cause failure of the Plunger Safety Switch. The
first is a mechanical failure and the second is a failure of the micro switch (Refer to Figure 4-24-1).
To test for these two situations proceed as follows:
Testing for Mechanical Failure
1.
Turn off the power to the ESP Cells by turning the Disconnect Switch on the ClearAir Main Electrical
Panel to the off position (Refer to Figure 4-23-1).
2.
Open the Electrical Compartment access doors.
3.
Push in the Plunger Safety Switch and verify that the Grounding Disc is pushing the micro switch
down until you can hear the click of the switch engaging (Refer to Figure 4-24-2). If it is not repair as
necessary. If it is working properly proceed to step #4.
Testing for Micro Switch Failure
1.
Push in the Plunger Safety Switch, and using a continuity tester test for continuity between the
“Common” (COM) and the “Normally Open” (NO) terminals of the micro switch (Refer to Figure 4-
24-2). If there is continuity the micro switch is good. If there is not continuity the micro switch
must be replaced.
Figure 4-24-1
Plunger Safety Switch
Not Pushed In Position
Micro Switch
Grounding Disc
NO
Terminal
Figure 4-24-2
Door Safety Switch
Pushed in Position
COM
Terminal
