Service Manual

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Contactor Operating Coil
Contactor operation is achieved by energizing an
operating coil located within the contactor. The
contactor coil is considered part of the control circuit
operating at 120 volts as described on page 10.
Noisy Contactor
In most cases, noisy or chattering contactor operation is due to voltage variations being supplied to the water
heater. Extended 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, see page 16.
In addition, debris between the contact plates will cause noisy operation.
Contactor Operation Testing
This procedure assumes control circuit is operating
correctly.
Provided that the water temperature in tank is within
the operating range of the thermostat, checking
contactor operation can be as simple as rotating the
thermostat dial and listening to the contactor(s) to see
if they respond to a call for heat.
1. Turn Power “ON” and rotate thermostat dial to the
maximum setting, with water temperature in tank
below the thermostat setting, the contactor(s) will
close. With the contacts closed, check for 120 volts
across operating coil terminals (see Figure 8).
A) 120 volts IS present, okay, go to step 2.
B) 120 volts NOT present, verify control circuit
operation.
2. Check for rated voltage across lower terminals of
contactor(s) (see Figure 9).
A) Rated voltage IS present, okay, go to step 3.
B) Rated voltage NOT present, replace contactor.
3. Rotate thermostat dial to the minimum setting.
With water temperature in tank above thermostat
setting, the contactor(s) will open. With the contacts
open, voltage should not be present at lower
terminals of contactor(s).
4. Check for 120 volts across operating coil terminals
(see Figure 8).
A) 120 volts IS present, verify control circuit
operation.
B) 120 volts NOT present, okay go to step 5.
5. Check for rated voltage across lower terminals of
contactor(s) (see Figure 9).
A) Rated voltage IS present, replace contactor.
B) Rated voltage NOT present, contactor is okay.
Figure 8
Figure 9
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