Our 3 group Cimbali M29 has lost some of its steam power. The machine is less than 2 years old and it used to steam 1 liter (35.2oz) of water from 80F to 160° in around 52-55 seconds. Now it takes around 70-73 seconds. This makes it more difficult to get good milk texture and it slows down significantly our drink preparation time. For comparison purposes, our 3gr Linea in our other shop takes 48-50 seconds to heat from 80 to 160F. (Using a Fluke digital thermometer)
I have cranked up the thermostat on the M29 to 1.3. The water temperature exiting the group is around 200F. The steam tips are clean, both steam wands are affected. I have yet to find in Belgium a steam wand brush but I doubt it is clogged. ? Thank you for your help.

Things to check for:

blockage (in tips, wand, valves and solenoids in the steam path)
steam valves may be due for a rebuild
change in boiler pressure?
change in boiler fill level?
scaling of boiler and or elements.

With a three gruppo in a commercial setting, I'd be picking up the phone for a professional repair.

Steam valves are pretty easy to work on. Here is the one from my Faema disassembled...




The catch is that both of the steam valves are affected. If it were a partial blockage in one valve, the other would still work just fine. Scale has a bad habit of doing what you are describing. The heating element gets caked with deposits and the boiler recovery is reduced.

Once you open a wand, the pressure in the boiler immediately drops. The pressure stat kicks on and the boiler heats to compensate to loss of pressure. If your heating element is large enough, the pressure will hold steady or rise as you steam. If the heating element is caked in scale, then the boiler does not rebound as fast and your stem pressure drops.

You may be best calling in a service person. If you break something on a home machine you are out of espresso for a few days while you repair it. In a cafe, you are out of business.