American Water Heater ITCE3-52/80/119 manual Contactors, Contactor Construction - How They Work

OPERATION & SERVICE

CONTACTORS

This section of the manual provides information on how contactors used on Electronic Control Models are constructed, how they work and how to test contactor operation - see Figure 2 on page 9 for location of the contactors on these models. Surface Mount Control Models are not equipped with contactors.

Contactor Construction - How They Work

Magnetic contactors are used on Electronic Control Models to energize and de-energize the heating elements. Power from the fuse blocks is supplied to the heating elements through three switches (3 poles) inside the contactor. Springs located inside the contactor hold the switch contacts open; the springs are compressed and the spring tension forces or holds the switch contacts in their normally open state.

The contactor’s switches are closed by an electromagnetic coil inside the base of the contactor. When a call for heat is activated the electronic control system sends 120 volts to the contactor’s electromagnetic coil. As current runs through the coil it becomes “magnetized” and overcomes the spring tension holding the switch contacts open. The switch contacts then close which in turn sends power to the heating elements. When the call for heat is satisfied the control system de-energizes the contactor coil and spring tension returns the contacts to their open position.

3 Pole Contactor Side View 3 Pole Contactor Internal Wiring

Heating Element

Power Circuit

Wiring Terminals

Electromagnetic

Contactor Coil Wiring

Terminals 120 VAC

T3	T2	T1
		3 Normally
		Open Switch
		Contacts
L3	L2	L1
		Electromagnetic
		Contactor Coil

3 Pole Contactor Side View - Cover Plate Removed

Contactor Springs

Hold Contacts Open

When Electromagnetic

Coil Is Not Energized

Servicing should only be performed by a Qualified Service Agent

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