Service manual

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That is the correct operation for the “water-curtain” pump. The only purpose of the lower spray arm is to
rinse off the bottom of the rack so fi nal rinsing can take place more easily. If the lower arm of the water
curtain were to spray with higher pressures, the water would layover the top of the tank divider and pump
out the water in the rinse tank. This would cause the machine to re-fi ll, which turns off the heater and takes
away the fi nal rinse pressure.
Another possible cause is when the spray arm defl ectors tabs are bent over (from operators banging the arm
on trash cans) causing a jet of water to spray into the wash tank. This results in no heat, no fi nal rinse
pressure on the clean end and high water and chemical usage. Bend the defl ector back so it is facing
straight up and down and check the sprays are likewise.
PUMP MOTORS
“The wash pump motor keeps tripping the overload?”
This is an indication that the motor is having a problem or there is a loss of one phase in the electrical power.
Testing the amp draw of the pump motor should run balanced with approximately 8 amps on each of the
three legs for three-phase. For single-phase the motor would draw about 12-15 amps on both legs. Before
changing motors, verify the electrical supply is correct. Some work in the building could have caused one
leg of power to be missing. This missing leg is a common cause for a tripping an overload and is often
overlooked.
“I replaced the motor, but it still trips the overload?”
The existing overload could have been damaged by the prior problem with the motor, especially if it was
reset many times before the new motor was installed. It is a good practice to replace the overload whenever
a motor is replaced.
“I put on a new pump motor. Now the new pump is making a lot of noise and there is no pressure in the
wash?”
For three-phase motors, there is a 50/50 chance of connecting the wires incorrectly and having it run
backwards. Switch any two wires at the motor and it will reverse rotation and the pump will operate quiet. It
did not hurt the motor.
TANK HEATERS
“How do I increase the temperature for the tank heater?”
The thermostat is located in the same box as the heater terminal. It is a cartridge type thermostat with a
center rod control. With a screwdriver, turn the center rod to the left (counterclockwise) to increase
temperature. It has a range of 100° below to 500° above zero. Turn until the thermostat light (located next
to the heater relay) comes on. Observe the dial thermometer and move the center rod until you reach the
correct set point. Typically 163°-on to 168°-off for high temp tank heat. Same is true for the rinse tank.
“Will mineral build up on the heating elements hurt them?”
Yes. The mineral buildup acts as insulation, thus shortening the heater’s life and also reducing the heating
energy that can be put into the water.