Replacing the Contactor

To avoid electrical shock or property damage, disconnect power before installing or servicing equipment. A qualified technician must perform the service procedures.

Checkout

1. Remove electrical power to unit.

   

2. Using crosshead screwdriver, remove the side panel closest to the controls.

   

3. Label and remove the wires from contactor.

   

4. Perform a check on the contactor as follows:

   Test Points	Results
   from 23 to 29	open circuit
   from 24 to 28	open circuit
   from 25 to 27	open circuit
   from 22 to 26	ohm reading 415

   SHOCK HAZARD To avoid electrical shock, perform relay checks or transformer checks as described as instructions.

   The following checks are performed with the wall circuit breaker closed and the main power switch in the ON position. Extreme caution should be taken. Make connections before applying power, take reading, and remove power before removing meter leads, or electrical shock could result.

5. With power reapplied, let unit start heating up.

6. Check voltage as follows:

   Test Points	Results
   from terminal 29 to 28	The voltage should read the same at each terminal.
   from terminal 27 to 28
   from terminal 27 to 29

Replacing

If contactor proves defective:

1. Remove the four screws securing the contactor to the bracket and remove contactor.

2. Install new contactor, replace wires, and replace side panel.

3. Restore power to unit.