A.O. Smith DSE-5, Руководство по обслуживанию

Страница: 38 / 84

OPERATION & SERVICE
Servicing should only be performed by a Qualified Service Agent
36
Contactor Inspection
A thorough visual inspection of the contactors should be performed as part of any regular
maintenance program and whenever the water heater is being serviced. Refer to the listed
Steps and images below for this procedure.
1 Secure power to the water heater at the main breaker or disconnect switch.
2 Verify with an AC volt meter that there is not any voltage present at the Power Distribution Block (see
Figure 2 on page 9) or the contactor on single element models.
3 Remove the top cover (two small screws) from the contactor.
4 Check for and remove any debris from the area surrounding the switch contacts. IE: ants will occasionally
infest the switch contacts and eventually cause the contactor to malfunction.
5 Physically test the mechanical spring action of the contactor by depressing the contactor mechanism. If the
action is not smooth and/or sticks - replace the contactor.
6 Perform a close visual inspection of the switch contacts. The contacts are silver plated and should be
smooth. Contactor chatter (see page 6), voltage spikes, arcing, excessive current along with normal wear
and tear can cause the normally smooth surface of the contacts to become burnt, pitted and damaged. In
extreme cases the contacts can “weld” together and permanently close the contacts. The switch contacts
are not replaceable. If the contacts show signs of excessive wear or damage - replace the contactor.
7 Replace the top cover on all contactors when inspection is complete.
Top View Cover Plate On Side View Cover Plate Removed Physically Operate Mechanical
Perform Close Visual Inspection
Of Switch Contacts
Spring Action Of Contactor
Press Down Here
3 Pole Contactor 4 Pole Contactor