4 Ohm Speaker with an "8 Ohm Minimum" Reciever

I recently put together a small system consisting of a NAD L54 receiver and a pair of Totem Dreamcatchers. The Dreamcatchers are a 4 Ohm Speaker. The NAD Manual states that the speakers should be 8 ohm minimum. Of course, I did not now this until I purchased everything and had all the components delivered. I would hate to sell the speakers, but I am worried I will damage the receiver.
If I use the system, am I risking damage ? The room that the system is in is very small, and the system will be played at low levels. Thank you.