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

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Servicing should only be performed by a Qualified Service Agent
25
OPERATION & SERVICE
Heating Element Amperage Test
This test should be considered as a first diagnostic procedure for the common service
complaints of no hot water or not enough hot water. The heating element amperage test
shown on this page is the best procedure to quickly determine which (if any) heating
elements are not working properly.
1 Ensure tank temperature is less than 100°F/38°C - dump water to lower tank temperature if necessary.
2 Adjust the temperature settings to ensure a call for heat is active for all heating elements. Raise the
Operating Set Point to 140°F or higher. Set all Differentials at 2°F - see pages 61 and 62.
3 Using a clamp style AC amp meter: set the amp meter to an AC amperage range just above the expected
amperage (100 AC amp range initially). The normal operating amps for all standard heating elements/
loops is provided in the tables on page 24 or it can be calculated using ohms law as explained on page 11.
Follow the procedure below that corresponds to the type, six or three wire element, of heating element
being tested - see explanation on pages 16 & 17. When measuring amperage clamp the jaws of the amp
meter around ONLY ONE WIRE at a time.
Six Wire Elements: Measure and record amperage by clamping the jaws of the amp meter around one
wire from each of the three element loops on the heating element being tested - three amp readings.
Ensure you are not measuring the amp draw of the same loop more than once. See the connection/wiring
diagram on pages 18 - 21 that corresponds to the power supply phase and type of contactor(s) installed on
the water heater being serviced. The three amp readings should be approximately the same.
Three Wire Elements: Measure and record amperage by clamping the jaws of the amp meter around
each of the three heating element wires - three amp readings. See the connection/wiring diagrams on
page 22. The three amp readings should be approximately the same.
Service Notes: If the measured amps on any heating element loop/wire is zero amps perform the Heating
Element Voltage test (page 26) and the Heating Element Resistance & Ground tests (pages 29 - 30).
If the measured amps on any heating element loop/wire is considerably less or more (± 20%) than the
normal operating amps shown in the tables on page 24 ensure the voltage and KW rating of those heating
elements are the correct ratings for the water heater being serviced - see the rating label on the water
heater and Heating Element Ratings on page 23. If the heating element voltage and KW ratings are correct
perform the Heating Element Resistance & Ground tests on pages 29 - 30. If the element voltage and KW
ratings do not match the rating label call the toll free Technical Support phone number listed on the back
cover of this manual for further assistance.
Measuring amperage on an electric heating element.
Make sure the jaws of the AC amp meter are clamped
around ONLY ONE WIRE from each heating element
at a time. Take 3 amp readings; one for each heating
element loop/wire. The three readings should be
approximately the same.
Three Wire Element Being Tested