Error 27 on Autoterm Air / Planar auxiliary heaters
Error 27 comes up every now and then, often in combination with error 11. The cause can usually be found in the installation.
What does error 27 mean
Error 27 means the fan is blocked; it doesn't turn at all, not even with a grinding noise. Error 11, on the other hand, means the fan still turns, but not as fast as it should.
Cause
There can be various reasons why the fan doesn't turn. It usually seizes right after the heater is installed, and not because, for example, the fan sucked in a sock during operation. The problem is caused by screwing the heater to the floor too tightly or unevenly, which causes the heater housing to warp.
Because the gap around the fan is very narrow in order to create optimal suction, a slight twist of the housing is enough to make the fan wheel rub or even block completely.
Avoiding the error
The four screws of the heater should be tightened with roughly the same force. Make sure the mounting surface is level. Mounting the heater on a beaded sheet metal panel, or partly on carpet and partly on wood, only works well with our installation flange, which compensates for such differences in the mounting surface.
If you are sure it is not caused by the mounting screws
Perhaps a foreign object has got into the heater. Pieces of transport packaging or similar can get past the fan wheel into the interior and block the fan there.
To check, you can simply open the four clips on the outside of the heater and remove the upper part of the housing. You now have a clear view, and parts that don't belong in the heater are easy to remove.
Conclusion
With error 11 or 27 the heater is not broken, but has usually just been slightly warped during installation. With a level mounting surface (use the installation flange) this can be fixed. If there is a foreign object in the heater, you can open the upper housing cover and remove it.