Looks good....loads fast. You need a logo! Those graphics design guys are good at what they do for a living.
^This.
I don't feel that the Current Promotions needs to be under Categories and on the top nav bar.
The word Search before the search field is unnecessary.
I think the site would be more easily navigated if the product names weren't the model number.
Separate the Product Manuals and How To Size a Compressor categories from the products.
The How To Size a Compressor image doesn't fit the frame of the website well and clicking on the "item" prompts an error page (at least on Chrome) for "This webpage has a redirect loop", the product manuals do the same thing.
Parts and Hot Deals are under Popular Brands.
Overall it's a very well constructed and clean looking site. I know of a few larger companies that could learn a thing or two from looking over your site.