For the answer to this question, we refer you to the following documents:

Normal storage vs CA storage.pdf 

Our CA installations are static installations, our “ship it fresh” solution has been specially developed to keep products in optimal condition during transport.

For CA storage it is very important that the cold store is built gas-tight because the oxygen content and CO2 concentrations are adjusted in relation to the standard atmosphere.

For example, in most cases the oxygen will be reduced extremely from 21% to <2%. If the cold store is not gas-tight, this concentration cannot be maintained.

That is why CA cells are built in a special way, including a gastight coating and a gastight door (FFT-Projects). A “standard” cold store cannot therefore simply be used for CA storage. It is, however, possible to install our palliflex systeem in a “standard” cold store because the palliflex units are gas-tight by themselves. The palliflex system is often used for the storage of soft fruit such as blueberries, red currants and cherries.

After a measurement, or at a set time, the scrubber will start, to maintain the set CO2 level in the cold store.

If the scrubber does not function, or does not function properly, the CO2 levels can rise. 

• Check the measured value of the cold store with a manual meter.
• Check whether the machine and cold store are active, and check the set value for the CO2 . 
• Check the waiting line for the scrubber of the measuring cabinet. 
• Check whether the fan of the scrubber works, not just the motor. The fan belt might be broken. 
• Check the adsorb and regenerate times. 
• Check the functioning of the scrubber valves, and the cold store valve.

The O2 in a cold store should remain stable during the storage season. Factors like gastightness of the cold stores, the weather (pressure differences), settings of the cooling, aeration, adsorber, etc all play a role. The cold store should be gas tight, so the production of CO2 is equal to the uptake of O2 . If there is a leak (door, floor, air buffer or valve), O2 can enter the cold store. 

• Check the set O2 values on the measuring cabinet or CO2 adsorber, and measure these manually.
• Check the gastightness of the cold store.
• Make sure there is no over- or underpressure during a cooling or defrosting action. If this happens, adjust the cooling. 
• Check the O2 level in the adsorber lung. This should be 3 to 3,5% higher than the average value in the active cold stores connected to the CO2 adsorber. The lung is only useful if the O2 level is below 10%. 
• Check the O2 and CO2 levels in the cold store before and after a scrubbing action. If the CO2 lowers, the CO2 adsorber functions well. If the O2 rises too much (more than 0,3%) there might be a leak in the circuit. 

In the beginning of the storage season, the O2 can be lowered with a VPSA. The VPSA has to have the right settings, and must be connected to the right cold store. It is also possible that the cold store is not (yet) closed well enough. If the O2 was already at a low level and rises rapidly, there usually is a different problem. 

• Check the set O2 values on the measuring cabinet or CO2 adsorber , and measure them manually. 
• Check the gastightness of the cold store. 
• Check the functioning, setting and O2 output of the VPSA.
• Check the functioning of the CO2 adsorber valves, and the cold store valve. 

The CO2 adsorber contains a sensor of paddle that measures the air flow. If the flow is different than usual, the sensor will trigger an alarm. If the sensor light turns red while the CO2 adsorber is active, the alarm is triggered. 

Check the CO2 adsorber valves and the cold store valves. If one valve doesn't open, the pressure difference will cause the alarm.