FRL units (Filter Regultaor + Lubricator) are used to remove forign partcles and moisture from the compressed air while the regulator allows us to set the output pressure and avoid fluctions in the down stream. Lubricator is used to add oil in the compressed air to help lubricate the valves, tools etc in the machine.
To select the corrcet size of the FRL unit we should consider the Flow Rate The FRL must have the capacity to meet the air flow rate requirement of the machine so that the machine works upto it's full capacity.
Below is a rough guide on the flow rate for different sizes
a) Size 1/4" - 1000 l/min
b) Size 1/2" - 2600 l/min
c) Size 3/4" - 8300 l/min
d) Size 1" - 8500 l/min
e) Size: 2" -20000 l/min

In FRL Unit - the most common issues are
1) Cartridge Blocked : with usage the cartridge (element used in filter) gets chocked / blocked. Check and replace the cartridge periodically to ensure efficient working of the Filter.
2) Regulator Diapgram Broken : The regulator uses a diaphragm to control the pressure. Sometimes when the regulator knob is tightened very hard - it may lead to the diaphragm getting torn. You can replace the diapgram in the regulator .
3) Filter and Lubricator Bowl : In case of external jerk / push on the bowl - it might leak. You can replace the bowl to rectify this issue.
4) Gauge Not Working : FESTO also provides spare gauges which can be replaced if required.

FRL Units are critical to any pneumatic system - as the air quality directly impacts the life and performance of the entire system.
FESTO FRL units are the best because they offer:
1) Filter Bowl with enough depth to hold the condensate water (very small bowls lead to moisture entering the system).
2) Economical and Easily replacable cartridge - if cartridge is not replaced periodically - the filter stops working.
3)Sturdy structure of the FESTO FRL units ensures that the FRL unit is able to perform even in harsh environments and do not get damaged easily with minor pushes or jerks (with is very common in industries)
4) FESTO FRL Units provides feature to lock the regulator - so that accidential touches do not change / alter the regulator set-up.
5) Modular Set-up :FESTO FRL units are Modular - so we can replace parts (as needed) without the need to remove the entire FRL unit.