If the error code F26 indicates that the pressure switch is faulty, then F27 only warns that there is not enough water to start the washing program. Before calling the master and preparing for the repair and replacement of components, check to see if enough fluid is entering the drum. Most likely, the reason is precisely this.
What is it talking about error F02find out by reading here.
What is a pressure switch?
One of the important parts of the washing machine is the water level sensor, which records the air pressure in the drum and, based on this information, determines how much is currently being collected. If the level matches the programmed one, the wash program begins. Any deviations from the norm will lead to the fact that the process does not start, and a disappointing code lights up on the control panel.
What if you find the code F27?
Check the pressure and the presence of water in the water supply system. If the pressure is clearly below normal, call the plumber or wait until it stabilizes and try to turn on the wash again;
Make sure the water tap is fully open;
Inspect the hose that connects the water system to the washing machine. Any excesses or blockages can interfere with the work. It is better to disconnect the hose completely and flush it under good pressure. Also make sure that the filters are not clogged.
After the steps described above, restart the control system: disconnect the washing machine from the mains for a quarter of an hour. Turn on and try to start any of the programs anew.
If all else fails, it's time to call the wizard. In this case, it will be necessary to repair or replace the filling valve, the hatch of the hatch door, the control module, or, of course, the liquid level sensor in the drum itself.