Ui24 pre delay doesn't appear to be working?

Russthedrummer

I recently purchased a UI24 and for the past 2 weeks I have been getting familiar with it.
One this that is puzzling me is the pre delay feature on the reverb effects, I cannot seem to hear the pre delay at all?
No doubt this is probably user error, please can someone explain how the pre delay is used - best setting etc..

Many thanks!