I offer the washer and dryer as amenities in my listing. My advice is to follow the KISS rule.
I keep it simple and provide laundry tabs and dryer sheets. It's very difficult to mess that up. I understand you have some expensive machines. But these things are built to last - 10-15 years for normal use, in most cases. I find that almost all of my guests use the laundry, even for 2 night stays.
As a guest, I would find it unreasonable to see laundry restrictions if I'm booking a shorter stay. Many guests travel from out of town, and being able to do laundry is a huge plus. These restrictions could result in lower occupancy rates, or a poor experience for your guests.
Most laundry machines are self-explanatory and don't require any instructions. This would be the way to keep it, but every circumstance is different. If you have to provide instructions, I would do so in the house rules and in a note like others have suggested.
To offset the cost of utilities, you can always raise your prices. The more restrictions and rules you have, the more friction it creates. And you want the least amount of friction possible!