Test a Contactor
This equipment operates at high voltages. Use extreme caution, observe all warnings,
and follow all safety procedures. Failure to observe safety precautions may result in
injury or death to personnel.
A properly operating contactor will audibly engage when activated. If a loud "clunk"
sound is heard when activating a component, the contactor mechanism is operating
correctly. The contactor should still be checked for voltage even if it appears to be
Ensure there is water in the water treatment system. If any of the sight glasses on the
Reuse, WTS, or Nano Feed tanks is full, drain the tank to a level approximately four
inches from the top of the sight glass tube before proceeding.
1. Ensure the boiler, P-1 pump, P-3 pump, or P-4 pump, as applicable, has been switched on at the
PLC and is in a position to be operating.
2. Open the PLC enclosure and locate the contactor (Figure 20, Item 37) to be tested.
3. Visually verify that the gray contactor bar (Figure 20, Item 38) is recessed within the contactor
(Figure 20, Item 37) when activated.
4. If the gray contactor bar (Figure 20, Item 38) is not recessed, check for 120 VAC between coil
terminals (Figure 20, Item 39) and ground.
5. Use a voltmeter to test for potential between terminals L1 (Figure 20, Item 40) and T1 (Figure 20,
Item 41). There should be no voltage reading between these two points.
6. Repeat Step 5 for terminals L2 and T2, and L3 and T3.
7. Replace an inoperative contactor (Figure 20, Item 37).
8. Close the PLC enclosure and monitor for normal operation.