Centre vents blow only in EC mode

[mun5]

Hi

We're having an issue with the centre air vents on my dad's C180. When EC is switched off, there's no/hardly any air coming out from the centre vents - but strong air comes from the side vents. We've tried all air speeds and positions. With EC switched on, air comes out fine from the centre vents as well. Does anyone know why this might be the case? Could a fuse be blown or something simple?

Any help appreciated.

[jnolte]

check the duo valve it sticks

[lingpoen]

where is this valve and how can i check it? thanks in advnace..

m

[andy_1100]

Here's avideo on the heater valve: https://youtu.be/C37Q6Ba80Y4