TIMER for MODEL 24L
General Description:
The timer is a self-contained (frame mounted) timer of the repeating cycle type. It is mounted on the lower control
panel of the Jackson Dishwashing Machine to control the automatic functions of this machine. It consists of a
clock motor which operates on 60 cycle, 110VAC. In addition to the clock motor, the timer also contains a driven
cam arrangement which operates five micro switches.
Principle of Operation:
The timer controls various operations of the automatic washers as per wiring diagram for each machine; however,
the timing cycle and the micro switches are the same for each model. The time for One Complete Revolution of the
cam shaft is approximately 360 seconds, allowing two wash and two rinse operations for each complete revolution
of the cam shaft. The micro switch nearest the timer motor is the hold circuit and uses both the NO and NC
contacts. The micro switch second from the timer motor controls the wash/rinse and uses the NC contact. The
micro switch third from the timer motor controls the rinse/fill and uses just the NC contact. The micro switch fourth
from the timer motor controls the drain and uses just the NC contact. The last micro switch, fifth from the timer
motor, controls the sanitizing pump and uses just the NC contact.
Service Instructions:
CAUTION: Always remove the power to the machine before working on the control panel or while servicing
the components in the door panel. All electrical checks should be made by qualified personnel.
Timer operation can be observed after removing the machine's kickplate by loosening the two screws holding it.
If it is determined that the timer is defective, it is recommended that a new timer be installed. If a new timer is not
available, limited field maintenance can be accomplished by changing the micro switch.
A frozen contact on a micro switch will be indicated by one function being executed all the time or the absence of a
click when the switch arm is actuated.
To Replace Micro Switch:
1. Remove all wires from the timer, properly tag them to assure proper replacement.
2. Remove the screws which hold the timer to the control panel.
3. One screw holds the micro switches, cams and actuating arms in the frame. This screw is seen on the
side opposite the motor. Remove this screw. Note: Be sure to note which cam goes with which micro
switch. Cam nearest timer motor has 1/2 raised and 1/2 depressed edge.
4. The unit can now be taken apart and the defective micro switch replaced.
5. Reassemble.
Note: The flanges on the cams are such that they only mesh in one direction.
The timers cam drive system is equipped with a clutch to enable one to view the operations of the cams
and micro switches. Remove power to machine before touching timer. Rotate cams by turning with fingers;
cams will turn in one direction only. Do not force them. As cams actuate switches, listen for the 'click' of
the switch or test the switches with an ohmmeter.
