Introduction: These oil protection controls are designed to provide protection against low net oil pressures on pressure-lubricated refrigeration compressors. The control unit measures the pressure difference between the pressure generated by the oil pump and the pressure of the refrigerant at the crankcase. The built-in delay switch allows for pressure pick-up at start-up and avoids annoying downtime during a short pressure drop during another run cycle**.
Indicates that when the compressor starts, the delay switch is energized. If the net oil pressure is not established within the specified time limit, the delay switch trips to stop the compressor. If the net oil pressure rises within the required time after the compressor starts, the delay switch will automatically power off and the compressor will continue to work normally. If the net oil pressure drops below the set value (scale pointer) during the operating cycle, the delay switch is energized and unless the net oil pressure returns to the entry point within the delay period, the compressor will stop and must be manually reset. In the case of low oil pressure, the compressor can never run for more than a predetermined time. The controls can only be used to manually reset the personnel cut-off.
These controls are designed to be used as operational controls only. If an operational control failure would result in personal injury or property damage, it is the installer's responsibility to add equipment or systems that prevent or warn of the control failure.
Delay switching or a time of 120 seconds applies to all models. The 230 VAC delay circuit requires 30 VA for 120 seconds of timing and 50 VA for 30 seconds of timing. The time delay unit is compensated to ensure consistent timing at ambient temperatures from 0 to +55°C. The timing is only affected by the voltage change. After locking has occurred, the delay switch has cooled down for at least 15 minutes and the control can be manually reset.
Time-delay heater circuits: The standard controller is equipped with a 230 VAC time-delay circuit. Special models are available with an additional 12 AC DC, 24 AC AC OR 115 230 VAC. Quantity orders only.
Repair and replacement timers and terminal block assemblies can be replaced as a complete unit. Other repairs are not recommended. When contacting the dealer for replacement, you should indicate the type and model of the control. This number can be found on the nameplate or cover label.