I had an alert appear on my MVHR controller for the pre filter. I haven't looked at these since the installation so took them out for the first time this evening.

It appears that despite being clearly marked up for the direction they should be, one has been put in upside down. Is the filter fabric uni-directional? I need to put the filters back in whilst I await replacements (I have vacuumed them) but my concern is that if I mount them both correctly the crud from the one that was the wrong way around will get into the unit.

Any advice, please?

Put it back the same way for now, it's been fine so far?

Depends on the filter medium.

Some is just the same stuff all the way through. Others use a courser filter first, then progressively finer.

The only time a single medium filter may cause a problem is if it has a supporting cage and different seals in one side.

Edited November 14, 20196 yr by SteamyTea