Refrigeration unit control with shutdown evaluation and automatic restart

A method of operating a refrigeration unit having high and low pressure sides, a refrigerant compressor connected between the high and low pressure sides, and pressure sensor means which monitors the high pressure side, comprising the steps of:

• monitoring the high pressure side of the refrigeration unit,
• shutting the refrigeration unit down when the monitoring step detects a first predetermined pressure which indicates an over-pressure condition,
• incrementing a shut down count when the refrigeration unit is shut down in response to the over-pressure condition,
• continuing the step of monitoring the high pressure side of the refrigeration unit during shut down,
• determining the value of the shut down count,
• restarting the refrigeration unit as a function of pressure of the high pressure side and the shut down count value, restarting the refrigeration unit only after the pressure monitoring step finds the pressure of the high pressure side has dropped below the first predetermined value to a second predetermined value, and then only when the determining step finds the value of the shut down count is less than a predetermined value,
• modifying the operation of the refrigeration unit to reduce the load on the compressor when the refrigeration unit is started by the restarting step,
• timing the operation of the refrigeration unit when started by the restarting step,
• and resetting the shut down count when the refrigeration unit operates for a predetermined period of time without being shut down again by the step of shutting the refrigeration unit in response to an over-pressure condition.

A method of operating a refrigeration unit having a refrigerant compressor driven by an internal combustion engine having a temperature sensor, comprising the steps of:

• monitoring the temperature of the internal combustion engine,
• initiating a first predetermined modification of the refrigeration unit which reduces the load on the internal combustion engine when the monitoring step detects a first predetermined over-temperature condition,
• shutting the internal combustion engine down when the monitoring step detects a predetermined maximum over-temperature condition,
• incrementing a shut down count when the internal combustion engine is shut down in response to the maximum over-temperature condition,
• determining the value of the shut down count,
• restarting the internal combustion engine as a function of the temperature of the internal combustion engine and the value of the shut down count, restarting the internal combustion engine only when the monitoring step detects the temperature of the internal combustion engine has dropped to a predetermined value, and then only when the determining step finds the shut down count value is below a predetermined count value,
• timing the operating time of the internal combustion engine when started by the restarting step,
• and resetting the shut down count when the internal combustion engine operates for a predetermined period of time without being shut down again in response to the predetermined maximum over-temperature condition.

A refrigeration unit, comprising:

• monitor means for monitoring a predetermined parameter of the refrigeration unit, a predetermined value of which indicates a mandatory shut down condition,
• means for shutting the refrigeration unit down in the event the monitor means indicates that the monitored parameter has reached the mandatory shut down condition,
• shut down counting means,
• means for incrementing the shut down counting means in response to the refrigeration unit being shut down by the mandatory shut down condition,
• said monitor means detecting when the predetermined monitored parameter has a value which permits restarting of the refrigeration unit,
• means for restarting the refrigeration unit in response to the monitor means finding that restarting of the refrigeration unit is permitted and the value of the shut down counting means is less than a predetermined value,
• means for modifying the operation of the refrigeration unit when restarted, with the modification being selected to reduce the probability of the monitored parameter from reaching the predetermined shut down condition,
• timing means for timing the operation of the refrigeration unit when started by the restarting step,
• and means for resetting the shut down counting means when the refrigeration unit operates for a predetermined period of time without a mandatory shut down.

A refrigeration unit having high and low pressure sides, a refrigerant compressor connected between the high and low pressure sides, and pressure sensor means disposed to sense the pressure of the high pressure side, with the pressure sensor means initiating shut down of the refrigeration unit down in response to detection of a predetermined over-pressure condition, comprising:

• shut down counting means,
• means incrementing the shut down counting means when the refrigeration unit is shut down in response to the predetermined over pressure condition,
• means restarting the refrigeration unit in response to the pressure sensor means and the shut down counting means, restarting the refrigeration unit only when the pressure sensor means finds the pressure of the high side has dropped below the first predetermined value to a second predetermined value, and then only when the value of the shut down counting means is less than a predetermined value,
• means modifying the operation of the refrigeration unit to reduce the load on the compressor when the refrigeration unit is started by the restarting means,
• timing means timing the operation of the refrigeration unit when started by the restarting means,
• and means resetting the shut down count when the refrigeration unit operates for a predetermined period of time without being shut down again in response to an over-pressure condition.

A refrigeration unit having a refrigerant compressor driven by an internal combustion engine, and temperature sensor means for sensing the temperature of the internal combustion engine, comprising:

• means initiating a first predetermined modification of the refrigeration unit which reduces the load on the internal combustion engine when the temperature sensor means detects a first predetermined over-temperature condition,
• shut down means for shutting the internal combustion engine down when the temperature sensor means detects a predetermined maximum over-temperature condition,
• shut down counting means,
• means incrementing said shut down counting means when the internal combustion engine is shut down in response to the maximum over-temperature condition,
• means for restarting the internal combustion engine as a function of the temperature of the internal combustion engine and the value of the shut down counting means, with said restart means restarting the internal combustion engine only when the temperature of the internal combustion engine has dropped to a predetermined value, and the value of the shut down counting means is below a predetermined count value,
• timing means for timing the operating time of the internal combustion engine when started by the restarting means,
• and means resetting the shut down counting means when the internal combustion engine has operated for a predetermined period of time without being shut down again by the shut down means.