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AJ-64 Conveyor Series Technical Manual 7610-003-30-93
Issued: 05-02-2006 Revised: N/A
SECTION 5: PARTS SECTION
61
HEATER ASSEMBLY (CONTINUED)
The wash tank heater system is electrically connected in the circuit so that they are dependent upon the dishwasher being prop-
erly filled with and maintaining a safe water level, two thermostats (mounted in the heater box behind the dress panel), float
switch (mounted in the wash tank), and the heater relay (mounted in control box) with the heater being activated by the ther-
mostats.
Once the dishwasher has been filled to the correct level, the heater should operate automatically. Should the tank heat be too
high, too low or no indication of temperatures at all, the following checkout should be made.
Note: The following checkout should be made by either a qualified service person or electrician.
A- Checkout of the heater system
1- If the temperature is too high, adjust thermostat using instructions on the page entitled “Thermostats”.
2- If temperature is too low, adjust thermostat as above, then:
a - Turn off power to machine by placing customer’s circuit breaker in the “OFF” position. Turn off machine
circuit breaker located on right side of control box.
b - Remove cover from control box on top of dishwasher.
c - Make sure water temperature is below 140° F.(preferably about 130°F.).
d - Turn on both circuit breakers. Observe heater relay (R1) while the power switch is turned “ON” and “OFF”.
If relay contacts move in and out, the heater relay is operating correctly: if not proceed to “C”.
B- If heater relay (R1) closes:
1 - Check power supply at incoming terminal board L1, L2 & L3. It should be the same voltage as indicated on
the machine data plate.
2 - Check power at connections on heater relay (R1). The voltage should agree with the voltage on the
machine data plate. If not, check wires for breaks or bad connections.
3 - Check power at terminals of heater which should agree with the data plate. If not check wires for breaks or
bad connections.
4 - Temperatures should rise as explained in “C-1”, and amperage may be checked according to those instruc-
tions. Replace any defective elements.
C - If heater relay (R1) does not close.
1 - There is an insulated movable insulated movable bar on relay across the top. With an insulated probe, depress
this bar and observe the thermometer: the temperature should rise noticeably in a minute or two. If it moves slow-
ly, it would indicate that the element is faulty. If it moves constantly higher at a good rate, elements should be
good.
Note: A check with an amp probe at heater relay (R1) terminals should be made to verify the amp draw on each leg.
This should be appropriate for the voltage and phase indicated on the data plate
HEATER PROTECTION & AUTOMATIC FILL
This control is activated when the power switch is turned “ON”. The primary function is to automatically energize the wash tank
heat circuit. It will also cutoff the wash tank heat circuit should the water be accidently drained from the machine with the power
switch still “ON”. The power switch should always be turned-off before draining the unit.
This water level control consists of two (2) floats that operate when the power switch is turned on and works in conjunction with
the thermostats and heater relays.
When the power switch is turned “ON” water starts to enter the dishmachine. When it reaches the proper level the normally
open contacts in the water level float switch close activating the heating circuit for tank heat.
If the water level below the correct level while power is still on, the float switch will sense the lack of water and de-activate the
heater.