CO2 laser not cutting correctly

Good day everyone

I need some guidance on a CO2 laser that is not cutting correctly.

Please note that some of my information is based on hear say.

My client has CO2 laser (JCUT-1612)with maximum of 38mA, the tube failed (60w) and was replaced by a secondhand tube (45w)....this information is hear say as I can not verify the wattage.

We have done the beam alignment perfect center to all mirrors and checked that everything is tight and all mirrors etc are in good condition.

When cutting 3mm acyclic square at 35% power (12mA)at 15% speed and different focal heights ranging between 6mm to 10mm, it will cut on one side but not the other side. The mA stays constant.

Here are a few issues I picked up:
1. Bed is warped in the center by 3.60mm
2. Water flow was incorrect but since been rectified.
3. Cooler is 30.50 degrees, Cooler fans not working.

I was told that the water temperature will not effect the performance of the laser, but according to my research it does. The ambient temperature is on a normal day around 30 degrees plus.

Does the water temperature have an effect on the laser performance?
What is the optimal coolant temperature?
What can be the root cause for it not cutting?
How can I test the second hand tube to know if its working correctly?

Thank you for any advice