Troubleshooting; Main Control - U-Line U-3018RFOL-00 Service Manual

Troubleshooting

Troubleshooting

Main Control

The main control board is very robust and is rarely the cause of
system issues. It is important to fully diagnose the board for any
suspected failures before attempting to remove the board for
replacement or service. Follow the guidelines below to fully test and
diagnose the main control.
Power Fault
If the unit does not (or seems to not) power on, follow the flow
chart below to help diagnose the issue. Before beginning it is
important to first verify the unit is not simply set to sabbath mode.
Check Voltage
No Voltage
At Wall Outlet
Voltage
Verify Voltage At Main
No Voltage
Control Voltage Input
Voltage
Check Fuse F1
No Continuity
For Continuity
Continuity
Connect Test Display To J5.
Cycle Power And Check For Operating
Operation
Not Operating
Is the door open? The
Yes
Display will not activate
while the door is closed
No
No
Open Door.
Is the UI Now
Functional?
Yes
26
Alert Customer
Of Power Failure
Replace
Power Cord
Replace
Fuse
Inspect Customer UI
and Data Cable
Is the Reed
Replace Reed
Switch Operating
No
Switch.
Properly?
Yes
Replace Main
Board
Testing The Main Control
If the main control is suspected of being faulty, the following
procedure should be performed to verify main control for
functionality.
Relay & DC Outputs
One of the primary functions of the main control is to operate the
multiple relay and DC outputs during each cycle. Verify proper
operation of these relays using the following procedure.
1. Enter "Relay Toggle" through the service menu.
NOTICE
Frequently toggling the compressor relay could force the
compressor into overload. The compressor will
automatically deactivate during an overload and will remain
deactivated until the overload switch cools. This could take
some time. It is important to allow the compressor at least
5 minutes off time between relay cycles.
2. Toggle the relay. Its related component should activate / deactivate
with the switching of the relay. If it does not, see "Component
Testing" on page 27.
Inputs
The main control monitors a number of thermistor inputs and switch
states during operation. It would be unlikely that an error in reading
an input would be at the board level. Always attempt to replace the
faulty switch or thermistor input with a known working sample to
verify proper board operation.
Other Suspected Main Control Faults
If other components have been ruled out as being faulty but the unit
continues to have operating issues, it is most likely due to a
configuration error. Configuration errors can be cleared by restoring
the unit to its factory default setting. Factory defaults may be
restored through the service menu. See page 17.
!
CAUTION
Precautions must be taken while working with live electrical
equipment. Be sure to follow proper safety procedures while
performing tests on live systems.
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