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SERVICE PROCEDURE MCE-X
Contactor Testing
Contactor Operation Testing
Noisy or chattering contactor operation in most cases is due to voltage variations being supplied to the water heater.
E
xtended periods of voltage variations will cause damage to the operating coil of the contactor causing noisy operation.
Determine that service voltage to the unit meets the electrical requirements per the rating plate located on the front of
the water heater.
In addition, debris between the contact plates will cause noisy operation.
Noisy Contactor
Contactor Operating Coils
Contactor operation is achieved by energizing an operating coil in response to a call for heat from the thermostat. There
are three different operating coils used depending on voltage rating of the water heater as follows:
Description Color Code
208/240 Volt Coil Green
277 Volt Coil Blue
480 Volt Coil Black
All the coils have a color code for visual conformation. In addition, the 277 & 480 volt coils are labeled with voltage rating
for proper identification. All contactors supplied for replacement are equipped with The 208/240 volt operating coil. By
removing the rear mounting plate of the contactor, the operating coils can be changed based on desired service voltage.
When contactor replacement is required be sure to order the proper operating coil base on the voltage rating found on
the rating plate located on the front of the water heater.
Color Code Location
Identification Label Location
Rear Mounting Plate
Operating Coil
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DANGER
High voltage exposure. To avoid hazard to
life or property, use extreme caution when
making voltage checks .
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