Jackson dishmachines Dishwasher User Manual


 
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SECTION 4: SERVICE PROCEDURES
WATER LEVEL CONTROL
WATER LEVEL CONTROL: This water level control is used on this machine in conjunction with a sensor, master switch, ther-
mostat all of which help control the action of the wash tank heater. The wash heater water level control is energized when the
master switch is turned on.
When the water level decreases in the wash tank, the sensor (probe) sends a signal to the control which deactivates the plug-
in relay (located on the control circuit board). When the relay deactivates, one set of its contacts return to a normally open posi-
tion. The thermostat and wash heater are connected in series with these contacts and at this time de-energizes the wash tank
heat circuit (thermostat & wash heaters). When the proper water level is restored the relay reactivates and closes the normal-
ly open contacts to energize the wash-heat circuit. Note: The master & heat switch must be on and the wash tub full to the
probe level for the wash-heat circuit to work.
SYMPTOMS OF LEVEL CONTROL FAILURE:
1. Wash-heat circuit not energized by control. (Wash temperature not maintained by heater.)
2. Wash heater stays on with machine master and heat switch on yet no water in wash tub.
PROCEED WITH CHECKOUT:
1. Remove power to machine by turning circuit breaker to its “OFF” position.
2. Remove the 4 screws holding the control panel on the control box. Remove panel and attach to one side of control box with
2 screws.
3. Locate wash-heat water level control board and disconnect wires going to terminals marked C & H. Mark and insulate wires
for replacement.
4. Re-apply power to machine. With an insulated jumper wire, touch jumper between terminals C & H, relay in clear plastic
cube should activate as wire touched to terminals, observe relay contacts, they should pull in.
5. If relay operates, the control can be deemed operational and other causes should be explored. EXAMPLE: Wash element
(open ore shorted) thermostat is defective or needs adjustment. See thermostat page for checkout.
6. If relay does not operate, replace control to see voltage is being applied to L1 - L2 marked on control.
7. In any case, always locate sensor (probe) inside wash tub and clean off all deposits (instruct customer, this should be done
on a weekly basis).
8. Other checks can be made using the wash tank heater system checkout shown on another page.
9. Remove power to machine and replace wires that were removed in the steps above.
Sensor, Lundy Probe