Service manual

AMERICAN DISH SERVICE

TECHNICAL SUPPORT MATERIAL

Routine and Preventative Maintenance

POOR or NO HEATING OF WASH TANK

ADC 44 Conveyor (11 gallon wash tank)

The 12 kW, 208v wash heater in an ADC 44 would normally draw 34 amps on each leg. The factory

setting of the thermostat is “on” at 161°F, “off” at 165°F. However, the NSF minimum temperature for the

wash tank is 150°F on a multiple tank conveyor (ADC-44/66), so it is permitted to operate at 150°F in high

temp sanitizing mode. The ADS thermostat is adjustable from 100°F below zero to 500°F above zero. To

turn it all the way up (left turns) would be a large error. The stirred tank principle (meaning unless stirred the

column of water will have differing levels of temperature) is common to any tank of water. For the ADC 44,

after running 3 to 5 racks, the water then equalizes after heating the pipes, pump, and walls of the machine.

NOTE: with a tank sitting and idling on the thermostat set point (161°F), the water in the sump and pump will

actually only be 90 -100°F. When mixed, this cooler water commonly drops the tank temp on start up. This

is true of any dishwasher; all water below the heater will remain lower in temperature. Once all the water

temps are mixed, the tank heater will begin to heat until all water reaches the set point. We should not set

the temperature at 170°F in the tank trying to compensate for this start up drop. Those ﬁ rst racks hit with

that high temperature will bake the starch on and results will suffer. Keep the factory set point, check for

disturbances, and follow installation instructions.

After start up, tank temperature will equalize if “disturbances” to the energy transfer process are not in

excess of the watts available. When the disturbances increase the cooling effect beyond the potential of the

watts, temperature drops. Spraying water out of a jet will have the greatest cooling effect on tank

temperature. It is a physical property of water being forced into the air through a jet; thermal energy is

transferred from the water because of evaporation.

Points about Disturbances

1. Low voltage to the heater—size heater kW according to available voltage. Volts are directly related to

watts.

2. Poor heater—check amps, look for water mineral build up on element (1/16 thick can reduce

effectiveness), look for burned elements

3. Filling during washing—table problems, sink problems. This turns off the heater.

4. Too much suction from HVAC—values about 400 cfm will draw air through the machine causing greater

evaporation.

5. Fans blowing on the employees also blow on or through the machine—point fans away from the machine