The new system is now working steadily, at around 1.8 (NI) - 2 (WI) liters per minute.
Before shutting the old system off, issues and anomalies with the flows (both NI and WI) were observed.
This phenomenon can be a consequence of the following issues:
Clogging in the piping
Clogging in the fittings
Clogging in the utilities
Old or damaged flowmeters
Presence of air
Insufficient circulators
Losses in the circuit
The new cooling system was designed specifically to comply to the correct water treatment and choice of materials to avoid future corrosion, deposition, erosion, pitting or biologic contamination and the flowmeters already in place were replaced. Air was completely removed and the circulator's power was doubled (from a single one for two branches to two separate ones).
Still, the measured flow of the new system was the same or lower than the old one, even when switching back to the old flowmeters, that show the same measurements as the new ones.
First thing that needs to be taken into account is that during the installation the system remained filled with still water for more than a month, so if any debris were present they might have deposited.
This is why Nicola, Piernicola and I carried out a thorough cleaning of every piece of piping and every fitting, laser area included, with air, mechanical friction, alcaline soap and both alcohol and ultrapure water ultrasound bath.
We inverted the laser's inlet and outlet from the circulators onwards and closed the system on itself at every level. The results are the following:
The flow up to the split among the utilities, under the bench, is 10 l/min.
After the splitting into 8 utilities, it decreases to 2 l/min (acceptable according to the laser manufacturer)
We tested every utility and found some beam dump to be completely clogged so that not even air could go through. The laser, nevertheless, after being cleaned with dust-free cloths and distilled watere, showed no working issues.
While dismantling and cleaning the old system, debris were collected and biological contamination was observed. They will be sent to an external laboratory to be analized.
Water pH was between 6 and 6.5.
TDS document addressing pollution in cooling systems coming soon