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

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PRE SERVICE CHECKS
Servicing should only be performed by a Qualified Service Agent
6
PRE SERVICE CHECKS
WIRING CONNECTIONS
With the power supply to the water heater turned off ensure the wiring connections are
properly tightened to all components including: high voltage terminal blocks, fuse blocks,
contactors and transformers.
Loose connections at any connection point will cause increased amperage and excessive
heat which can damage wiring and components. Whenever worn or damaged wiring and
components must be replaced ensure all wiring connections are properly tightened before
putting the water heater back in service.
SERVICE PRECAUTIONS
1 DO NOT energize the branch circuit supplying power to the water heater or test the
water heater electrical system before the water heater is completely filled with water.
Read the start up procedures in the Instruction Manual that came with the water heater.
2 Be sure to turn off power and use a lock out device at the branch circuit power supply
disconnect switch or breaker when servicing the electrical system of the water heater.
Never touch electrical components with wet hands or when standing in water.
3 When replacing heating elements ensure they are rated at the correct voltage and KW
for the water heater being serviced see pages 23 and 31.
4 When replacing fuses use an insulated fuse puller to remove and install fuses. Always
use the correct size for the circuit. See the Instruction Manual that came with the water
heater for fuse size requirements. See page 15 in this manual.
5 Using an AC volt meter measure the branch circuit power supply voltage to the water
heater. Ensure the measured voltage of the branch circuit supplying power to the water
heater matches the water heater’s rating label - see pages 12 - 14.
6 Ensure the phase of the branch circuit supplying power to the water heater matches the
water heater’s rating label. Some water heater models covered by this Service Manual
are phase convertible. Some models are not phase convertible. See the Instruction
Manual that came with the water heater for more information on phase conversions.
7 The water heaters covered by this manual have a multi tap control circuit transformer.
This is a step down transformer that outputs 120 VAC (secondary winding) which is used
to power the electronic control system and energize the contactor coils. The transformer
can accommodate different power supply voltages and has multiple input voltage
connections or “taps.” Ensure the input supply voltage (primary winding) wiring to the
transformer is connected properly. See the Instruction Manual that came with the water
heater and pages 39 & 40 in this manual for more information.
Service Note - Contactor Chatter: Incorrect supply voltage wiring to the multiple tap 120
VAC Control Circuit Transformer will cause low/high output voltage from the transformer.
This can cause contactors to open and close their contacts rapidly (contactor chatter) and
result in permanent damage to the contactors. See pages 39 & 40.