Jackson 100 B/PRB, Service Manual, Page: 19 / 55

WASH TANK HEATER SYSTEM
FUNCTION
The Wash Tank Heater System is electrically connected in the circuit so that it is dependent upon the
dishwasher being properly filled with and maintaining a safe water level. The automatic fill system, therefore, should
operate properly before the heat system can be engaged. The circuit is controlled by a heat switch (mounted on the
front control panel), a water level control (mounted in the control box), a thermostat (mounted behind the lower front
panel), and a heater relay (mounted behind the lower front panel), and a heater relay (mounted in the control box),
with the coil being activated by the thermostat.
INDICATORS OF POSSIBLE MALFUNCTION
Once the machine has been properly filled and the heat system engaged, the heat circuit should operate by
merely turning on the heat switch. Should the wash tank be either too high, too low, or no indication of temperature
at all, the following checkouts should be made.
CHECKOUT OF HEATER SYSTEM FOR WASH TANK (Refer to drawing, fig. 2)
NOTE: THE FOLLOWING CHECKOUTS SHOULD BE DONE BY A QUALIFIED SERVICE PERSON OR
ELECTRICIAN.
1. If temperature is too high: adjust thermostat, using thermostat instructions in this manual.
2. If temperature is too low: adjust thermostat, using thermostat instructions in this manual.
3. If step one or two does not correct the problem, proceed as follows:
a. Turn off power to machine by tripping customer circuit breaker to "off" position.
Turn machine circuit breaker on right side of control box to "off".
b. Remove control panel from control box. Remount panel to right side, using two
screws, with the backside of panel facing you. c. Reapply
power to unit.
d. Wash tank must be emptied, then refilled for each checkout.
e. Wash temperature must be 130 degrees or less. Observe wash heater open switching
relay (two pole; only one pole used), located top relay on left side. With master
switch on, turn heat switch on and off; if relay contacts move in and out. see instructions
under BB. if not. proceed.
AA - - If heat relay doesn't close:
1. There's an insulated bar across the top of two contacts. With insulate probe, depress this bar and
observe wash thermometer; temperature should rise slowly. Watch for approximately five minutes; if
temperature doesn't rise, replace element. If amprobe E is used, the element should draw
approximately 7 amps.
2. With master and heat switches on:
a. Check position 1, figure 2. Voltage should be 220V. If not, check out and replace heat switch.
b. Check position 2; there should be no voltage. If there is, readjust thermostat
per thermostat adjustment instructions.
b. Check position 3; voltage should be approximately 120V to ground.
d. If voltage being applied on positions 1, 2, and 3 checks out okay, then the
relay should be replaced. Coil is probably defective.
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