Part 6:
SERVICE TROUBLESHOOTING
6.2 Operation Sequence and Timing Charts
Sections 6.2.1 through 6.2.3 explain the operation and timing of the dishwasher models.
6.2.1 Operation Sequence (Model UH-200B, UH-200)
Refer to the operation sequence below and the timing chart on the next page.
Upon application of
Input power
- all outputs are initially de-energized and the display is dis-
abled. Momentary closure of the
Power Pushbutton
enables the solid state controls, program
jumpers are read and the auto-fill sequence is initiated.
The
Fill/Rinse Valve
opens until the water level reaches the middle sensor of the
Water Level
Probe
. The
Detergent Pump
is cycled three times during the initial fill.
The
Wash Tank Heater
(All Models), which was locked out during the initial fill, begins to heat.
The
Booster,
which was locked out during the initial fill, begins to heat (UH-200B Only).
If the
Cycle Start Pushbutton
is pressed during the fill, the
Cycle LED
illuminates.
The Wash Cycle starts after the fill is complete.
Pressing the
Cycle Start Pushbutton
activates the Cycle LED and initiates the Wash Cycle.
The
Wash Pump Motor
is activated for 60 seconds. The
Detergent Pump
is activated for
1 to a maiximum of 30 seconds. The detergent pump is locked out after the fill valve closes.
The
Drain Valve and Drain Pump
are then activated until the water level reaches the bottom
sensor on the
Water Level Probe
.
The
Rinse LED
illuminates and the
Fill/Rinse Valve
opens until the water level reaches the
middle sensor of the Water Level Probe and 11 seconds has expired.
The
Rinse Aid Pump
is activated for 1 to 11 seconds during the last 11 seconds of the final rinse.
The
Cycle LED
is deactivated. The 90-second cycle is complete.
If the Cycle Pushbutton is not activated for (4) hours, the machine goes into the auto-shutdown
cycle and turns off.
If the
Door Safety Switch
is opened, all Pumps and Valves are disabled and times are held.
Closing the door re-enables Pumps and Valves and resumes timing from the point door was
opened.
If the
Power Pushbutton
is closed while the machine is running, the
Auto-shutdown Cycle
is
initiated. The
Touchpad/Display flashes
888’s. The
Drain Valve and Drain Pump
are activated
for 20 seconds. The
Fill/Rinse Valve
is activated for 10 seconds. The
Drain Valve and Drain
Pump
are then reactivated for 60 seconds. Then the machine turns off.
Closure of the
Extended Wash Pushbutton
during the Wash Cycle activates the
Extended
Wash LED
and extends the wash beyond normal wash time until the Extended Wash Pushbutton
is re-closed, de-activating the Extended Wash LED.
The
Chemical Pump Prime Switch
is enabled any time the Temperature Display is active.
The
Water Level Probe
is ignored during the wash cycle.
If the water level reaches the topmost sensor (overfill condition) of the
Water Level Probe
, then,
the
Drain Valve/Drain Pump
are activated until the water level drops below the lower sensor of
the water level probe.
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