TemperZone Econex Pro - UC8 Controller Protections and Timers; Safety Timer Durations

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8 Other alarms
The Master Controller performs many other protection
functions. For example:
• Signals from sensors and transducers must remain inside
normal operating range.
• Modbus RTU communications with Carelc.pCO and Carel
Power+ inverter) must continue uninterrupted.
• Modbus RTU communications with a controller such
as a BMS that is controlling the unit must continue
uninterrupted.
Refer to document ‘UC8 Troubleshooting Guide’ for details.
9 Lock-out
Each protection function has a trip counter. A trip counter
is reset to 0 whenever the compressor run request is
removed. Any trip that has occurred more than 12 hours
ago is removed from the trip count. For some protection
functions, when the trip counter reaches value 3 (i.e. three
consecutive trips occur) then the unit is “locked out”.
When a unit is locked out the compressor is not allowed to
start. Lock-out is designed to protect the compressor from
repeatedly starting when a serious fault exists that requires
the attention of a service technician.
The display shows the code of the fault that caused the
lock-out condition.
A unit that is locked out can be unlocked using any one of
the following methods:
• Remove mains power from the unit for at least 3 seconds,
then restore power.
• Issue an ‘unlock’ command via Modbus RTU serial
communications.
• Reset the controller via Modbus RTU serial
communications.
10 Safety timers
Each UC8 slave controller receives control signals and
transfers the signals to the outputs after enforcing safety
timers and other protection functions. If the compressor is
held off, or held on, by a safety timer then the
display shows message ‘H-O-L-d’.
Normal durations of safety timers are:
• Minimum off time 3 minutes
• Minimum run time 1.5 minutes
• Min. cycle time 6 minutes (up to 10 compressor
starts per hour)
• Min. mode change-over time
10 minutes (cooling to heating or
vice-versa)
Note:
If a unit operates on low capacity for extended periods then
the unit may periodically perform oil ush cycles. Under
such operating conditions compressor lubricating oil may
slowly settle in parts of the refrigeration system other than
the compressor; oil ush cycles help to return the lubricating
oil to the compressor. During an oil ush cycle compressor
capacity is increased to a certain minimum. The duration of
an oil ush cycle is 1 minute.